Merge branch 'master' into soc-2019-openxr

106 files changed, 1508 insertions, 549 deletions

diff --git a/add_camera_rigs/__init__.py b/add_camera_rigs/__init__.py
index faf06314..6f9f9eeb 100644
--- a/add_camera_rigs/__init__.py
+++ b/add_camera_rigs/__init__.py
@@ -18,13 +18,12 @@
 
 bl_info = {
     "name": "Add Camera Rigs",
-    "author": "Wayne Dixon, Brian Raschko, Kris Wittig, Damien Picard",
-    "version": (1, 4, 2),
+    "author": "Wayne Dixon, Brian Raschko, Kris Wittig, Damien Picard, Flavio Perez",
+    "version": (1, 4, 3),
     "blender": (2, 80, 0),
     "location": "View3D > Add > Camera > Dolly or Crane Rig",
     "description": "Adds a Camera Rig with UI",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "camera/camera_rigs.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/camera/camera_rigs.html",
     "tracker_url": "https://github.com/waylow/add_camera_rigs/issues",
     "category": "Camera",
 }
diff --git a/add_camera_rigs/build_rigs.py b/add_camera_rigs/build_rigs.py
index 1a37bc6e..57cadc0e 100644
--- a/add_camera_rigs/build_rigs.py
+++ b/add_camera_rigs/build_rigs.py
@@ -17,18 +17,33 @@
 # ##### END GPL LICENSE BLOCK #####
 
 import bpy
-from bpy_extras import object_utils
 from bpy.types import Operator
-from math import radians, pi
+from bpy_extras import object_utils
+from mathutils import Vector
 from rna_prop_ui import rna_idprop_ui_prop_get
+from math import pi
+
 from .create_widgets import (create_root_widget,
-                             create_widget,
-                             create_camera_widget,
-                             create_aim_widget,
-                             )
+                             create_camera_widget, create_aim_widget,
+                             create_circle_widget, create_corner_widget)
+
+
+def create_prop_driver(rig, cam, prop_from, prop_to):
+    """Create driver to a property on the rig"""
+    driver = cam.data.driver_add(prop_to)
+    driver.driver.type = 'SCRIPTED'
+    var = driver.driver.variables.new()
+    var.name = 'var'
+    var.type = 'SINGLE_PROP'
 
+    # Target the custom bone property
+    var.targets[0].id = rig
+    var.targets[0].data_path = 'pose.bones["Camera"]["%s"]' % prop_from
+    driver.driver.expression = 'var'
 
-def create_dolly_bones(rig, bone_layers):
+
+def create_dolly_bones(rig):
+    """Create bones for the dolly camera rig"""
     bones = rig.data.edit_bones
 
     # Add new bones
@@ -39,7 +54,7 @@ def create_dolly_bones(rig, bone_layers):
     ctrl_aim_child = bones.new("Aim_shape_rotation-MCH")
     ctrl_aim_child.head = (0.0, 10.0, 1.7)
     ctrl_aim_child.tail = (0.0, 11.0, 1.7)
-    ctrl_aim_child.layers = bone_layers
+    ctrl_aim_child.layers = tuple(i == 1 for i in range(32))
 
     ctrl_aim = bones.new("Aim")
     ctrl_aim.head = (0.0, 10.0, 1.7)
@@ -57,7 +72,8 @@ def create_dolly_bones(rig, bone_layers):
     ctrl_aim_child.parent = ctrl_aim
 
 
-def create_crane_bones(rig, bone_layers):
+def create_crane_bones(rig):
+    """Create bones for the crane camera rig"""
     bones = rig.data.edit_bones
 
     # Add new bones
@@ -68,7 +84,7 @@ def create_crane_bones(rig, bone_layers):
     ctrl_aim_child = bones.new("Aim_shape_rotation-MCH")
     ctrl_aim_child.head = (0.0, 10.0, 1.7)
     ctrl_aim_child.tail = (0.0, 11.0, 1.7)
-    ctrl_aim_child.layers = bone_layers
+    ctrl_aim_child.layers = tuple(i == 1 for i in range(32))
 
     ctrl_aim = bones.new("Aim")
     ctrl_aim.head = (0.0, 10.0, 1.7)
@@ -112,34 +128,13 @@ def create_crane_bones(rig, bone_layers):
     pose_bones["Crane_height"].lock_scale = (True, False, True)
 
 
-def build_camera_rig(context, mode):
-    bone_layers = tuple(i == 1 for i in range(32))
-    view_layer = bpy.context.view_layer
-
-    rig_name = mode.capitalize() + "_Rig"
-    rig_data = bpy.data.armatures.new(rig_name)
-    rig = object_utils.object_data_add(context, rig_data, name=rig_name)
-    rig["rig_id"] = "%s" % rig_name
-    view_layer.objects.active = rig
-    rig.location = context.scene.cursor.location
-
-    bpy.ops.object.mode_set(mode='EDIT')
-
-    # Add new bones
-    if mode == "DOLLY":
-        create_dolly_bones(rig, bone_layers)
-    elif mode == "CRANE":
-        create_crane_bones(rig, bone_layers)
-
+def setup_3d_rig(rig, cam):
+    """Finish setting up Dolly and Crane rigs"""
     # Jump into object mode and change bones to euler
     bpy.ops.object.mode_set(mode='OBJECT')
     pose_bones = rig.pose.bones
-    for b in pose_bones:
-        b.rotation_mode = 'XYZ'
-
-    # Add custom properties to the armature’s Camera bone,
-    # so that all properties may be animated in a single action
-    # Add driver after the camera is created
+    for bone in pose_bones:
+        bone.rotation_mode = 'XYZ'
 
     # Lens property
     pb = pose_bones['Camera']
@@ -150,22 +145,6 @@ def build_camera_rig(context, mode):
     prop["max"] = 1000000.0
     prop["soft_max"] = 5000.0
 
-    # DOF Focus Distance property
-    pb = pose_bones['Camera']
-    pb["focus_distance"] = 10.0
-    prop = rna_idprop_ui_prop_get(pb, "focus_distance", create=True)
-    prop["default"] = 10.0
-    prop["min"] = 0.0
-
-    # DOF F-Stop property
-    pb = pose_bones['Camera']
-    pb["aperture_fstop"] = 2.8
-    prop = rna_idprop_ui_prop_get(pb, "aperture_fstop", create=True)
-    prop["default"] = 2.8
-    prop["min"] = 0.0
-    prop["soft_min"] = 0.1
-    prop["soft_max"] = 128.0
-
     # Build the widgets
     root_widget = create_root_widget("Camera_Root")
     camera_widget = create_camera_widget("Camera")
@@ -176,7 +155,7 @@ def build_camera_rig(context, mode):
     pose_bones["Aim"].custom_shape = aim_widget
     pose_bones["Camera"].custom_shape = camera_widget
 
-    # Set the "At" field to the child
+    # Set the "At" field to the shape mecanism
     pose_bones["Aim"].custom_shape_transform = pose_bones["Aim_shape_rotation-MCH"]
 
     # Add constraints to bones
@@ -189,55 +168,359 @@ def build_camera_rig(context, mode):
     con.subtarget = "Aim"
     con.use_target_z = True
 
-    # Change display to BBone: it just looks nicer
-    bpy.context.object.data.display_type = 'BBONE'
-    # Change display to wire for object
-    bpy.context.object.display_type = 'WIRE'
+    cam.data.display_size = 1.0
+    cam.rotation_euler[0] = pi / 2.0  # Rotate the camera 90 degrees in x
+
+    create_prop_driver(rig, cam, "lens", "lens")
+
+
+def create_2d_bones(context, rig, cam):
+    """Create bones for the 2D camera rig"""
+    scene = context.scene
+    bones = rig.data.edit_bones
+
+    # Add new bones
+    bones = rig.data.edit_bones
+    root = bones.new("Root")
+    root.tail = Vector((0.0, 0.0, 1.0))
+    root.show_wire = True
+
+    ctrl = bones.new('Camera')
+    ctrl.tail = Vector((0.0, 0.0, 1.0))
+    ctrl.show_wire = True
+
+    left_corner = bones.new("Left_corner")
+    left_corner.head = (-3, 10, -2)
+    left_corner.tail = left_corner.head + Vector((0.0, 0.0, 1.0))
+    left_corner.show_wire = True
+
+    right_corner = bones.new("Right_corner")
+    right_corner.head = (3, 10, -2)
+    right_corner.tail = right_corner.head + Vector((0.0, 0.0, 1.0))
+    right_corner.show_wire = True
 
+    corner_distance_x = (left_corner.head - right_corner.head).length
+    corner_distance_y = -left_corner.head.z
+    corner_distance_z = left_corner.head.y
+
+    center = bones.new("Center-MCH")
+    center.head = ((right_corner.head + left_corner.head) / 2.0)
+    center.tail = center.head + Vector((0.0, 0.0, 1.0))
+    center.layers = tuple(i == 1 for i in range(32))
+    center.show_wire = True
+
+    # Setup hierarchy
+    ctrl.parent = root
+    left_corner.parent = root
+    right_corner.parent = root
+    center.parent = root
+
+    # Jump into object mode and change bones to euler
+    bpy.ops.object.mode_set(mode='OBJECT')
+    pose_bones = rig.pose.bones
+    for bone in pose_bones:
+        bone.rotation_mode = 'XYZ'
+
+    # Bone drivers
+    center_drivers = pose_bones["Center-MCH"].driver_add("location")
+
+    # Center X driver
+    driver = center_drivers[0].driver
+    driver.type = 'AVERAGE'
+
+    for corner in ('left', 'right'):
+        var = driver.variables.new()
+        var.name = corner
+        var.type = 'TRANSFORMS'
+        var.targets[0].id = rig
+        var.targets[0].bone_target = corner.capitalize() + '_corner'
+        var.targets[0].transform_type = 'LOC_X'
+        var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+    # Center Y driver
+    driver = center_drivers[1].driver
+    driver.type = 'SCRIPTED'
+
+    driver.expression = '({distance_x} - (left_x-right_x))*(res_y/res_x)/2 + (left_y + right_y)/2'.format(distance_x=corner_distance_x)
+
+    for direction in ('x', 'y'):
+        for corner in ('left', 'right'):
+            var = driver.variables.new()
+            var.name = '%s_%s' % (corner, direction)
+            var.type = 'TRANSFORMS'
+            var.targets[0].id = rig
+            var.targets[0].bone_target = corner.capitalize() + '_corner'
+            var.targets[0].transform_type = 'LOC_' + direction.upper()
+            var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+        var = driver.variables.new()
+        var.name = 'res_' + direction
+        var.type = 'SINGLE_PROP'
+        var.targets[0].id_type = 'SCENE'
+        var.targets[0].id = scene
+        var.targets[0].data_path = 'render.resolution_' + direction
+
+    # Center Z driver
+    driver = center_drivers[2].driver
+    driver.type = 'AVERAGE'
+
+    for corner in ('left', 'right'):
+        var = driver.variables.new()
+        var.name = corner
+        var.type = 'TRANSFORMS'
+        var.targets[0].id = rig
+        var.targets[0].bone_target = corner.capitalize() + '_corner'
+        var.targets[0].transform_type = 'LOC_Z'
+        var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+    # Bone constraints
+    con = pose_bones["Camera"].constraints.new('DAMPED_TRACK')
+    con.target = rig
+    con.subtarget = "Center-MCH"
+    con.track_axis = 'TRACK_NEGATIVE_Z'
+
+    # Build the widgets
+    left_widget = create_corner_widget("Left_corner", reverse=True)
+    right_widget = create_corner_widget("Right_corner")
+    parent_widget = create_circle_widget("Root", radius=0.5)
+    camera_widget = create_circle_widget("Camera_2D", radius=0.3)
+
+    # Add the custom bone shapes
+    pose_bones["Left_corner"].custom_shape = left_widget
+    pose_bones["Right_corner"].custom_shape = right_widget
+    pose_bones["Root"].custom_shape = parent_widget
+    pose_bones["Camera"].custom_shape = camera_widget
+
+    # Lock the relevant loc, rot and scale
+    pose_bones["Left_corner"].lock_rotation = (True,) * 3
+    pose_bones["Right_corner"].lock_rotation = (True,) * 3
+    pose_bones["Camera"].lock_rotation = (True,) * 3
+    pose_bones["Camera"].lock_scale = (True,) * 3
+
+    # Camera settings
+
+    cam.data.sensor_fit = "HORIZONTAL"  # Avoids distortion in portrait format
+
+    # Property to switch between rotation and switch mode
+    pose_bones["Camera"]['rotation_shift'] = 0.0
+    prop = rna_idprop_ui_prop_get(pose_bones["Camera"], 'rotation_shift', create=True)
+    prop["min"] = 0.0
+    prop["max"] = 1.0
+    prop["soft_min"] = 0.0
+    prop["soft_max"] = 1.0
+    prop["description"] = 'rotation_shift'
+
+    # Rotation / shift switch driver
+    driver = con.driver_add('influence').driver
+    driver.expression = '1 - rotation_shift'
+
+    var = driver.variables.new()
+    var.name = 'rotation_shift'
+    var.type = 'SINGLE_PROP'
+    var.targets[0].id = rig
+    var.targets[0].data_path = 'pose.bones["Camera"]["rotation_shift"]'
+
+    # Focal length driver
+    driver = cam.data.driver_add('lens').driver
+    driver.expression = 'abs({distance_z} - (left_z + right_z)/2 + cam_z) * 36 / frame_width'.format(distance_z=corner_distance_z)
+
+    var = driver.variables.new()
+    var.name = 'frame_width'
+    var.type = 'LOC_DIFF'
+    var.targets[0].id = rig
+    var.targets[0].bone_target = "Left_corner"
+    var.targets[0].transform_space = 'WORLD_SPACE'
+    var.targets[1].id = rig
+    var.targets[1].bone_target = "Right_corner"
+    var.targets[1].transform_space = 'WORLD_SPACE'
+
+    for corner in ('left', 'right'):
+        var = driver.variables.new()
+        var.name = corner + '_z'
+        var.type = 'TRANSFORMS'
+        var.targets[0].id = rig
+        var.targets[0].bone_target = corner.capitalize() + '_corner'
+        var.targets[0].transform_type = 'LOC_Z'
+        var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+    var = driver.variables.new()
+    var.name = 'cam_z'
+    var.type = 'TRANSFORMS'
+    var.targets[0].id = rig
+    var.targets[0].bone_target = "Camera"
+    var.targets[0].transform_type = 'LOC_Z'
+    var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+    # Orthographic scale driver
+    driver = cam.data.driver_add('ortho_scale').driver
+    driver.expression = 'abs({distance_x} - (left_x - right_x))'.format(distance_x=corner_distance_x)
+
+    for corner in ('left', 'right'):
+        var = driver.variables.new()
+        var.name = corner + '_x'
+        var.type = 'TRANSFORMS'
+        var.targets[0].id = rig
+        var.targets[0].bone_target = corner.capitalize() + '_corner'
+        var.targets[0].transform_type = 'LOC_X'
+        var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+    # Shift driver X
+    driver = cam.data.driver_add('shift_x').driver
+
+    driver.expression = 'rotation_shift * (((left_x + right_x)/2 - cam_x) * lens / abs({distance_z} - (left_z + right_z)/2 + cam_z) / 36)'.format(distance_z=corner_distance_z)
+
+    var = driver.variables.new()
+    var.name = 'rotation_shift'
+    var.type = 'SINGLE_PROP'
+    var.targets[0].id = rig
+    var.targets[0].data_path = 'pose.bones["Camera"]["rotation_shift"]'
+
+    for direction in ('x', 'z'):
+        for corner in ('left', 'right'):
+            var = driver.variables.new()
+            var.name = '%s_%s' % (corner, direction)
+            var.type = 'TRANSFORMS'
+            var.targets[0].id = rig
+            var.targets[0].bone_target = corner.capitalize() + '_corner'
+            var.targets[0].transform_type = 'LOC_' + direction.upper()
+            var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+        var = driver.variables.new()
+        var.name = 'cam_' + direction
+        var.type = 'TRANSFORMS'
+        var.targets[0].id = rig
+        var.targets[0].bone_target = "Camera"
+        var.targets[0].transform_type = 'LOC_' + direction.upper()
+        var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+    var = driver.variables.new()
+    var.name = 'lens'
+    var.type = 'SINGLE_PROP'
+    var.targets[0].id_type = 'CAMERA'
+    var.targets[0].id = cam.data
+    var.targets[0].data_path = 'lens'
+
+    # Shift driver Y
+    driver = cam.data.driver_add('shift_y').driver
+
+    driver.expression = 'rotation_shift * -(({distance_y} - (left_y + right_y)/2 + cam_y) * lens / abs({distance_z} - (left_z + right_z)/2 + cam_z) / 36 - (res_y/res_x)/2)'.format(distance_y=corner_distance_y, distance_z=corner_distance_z)
+
+    var = driver.variables.new()
+    var.name = 'rotation_shift'
+    var.type = 'SINGLE_PROP'
+    var.targets[0].id = rig
+    var.targets[0].data_path = 'pose.bones["Camera"]["rotation_shift"]'
+
+    for direction in ('y', 'z'):
+        for corner in ('left', 'right'):
+            var = driver.variables.new()
+            var.name = '%s_%s' % (corner, direction)
+            var.type = 'TRANSFORMS'
+            var.targets[0].id = rig
+            var.targets[0].bone_target = corner.capitalize() + '_corner'
+            var.targets[0].transform_type = 'LOC_' + direction.upper()
+            var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+        var = driver.variables.new()
+        var.name = 'cam_' + direction
+        var.type = 'TRANSFORMS'
+        var.targets[0].id = rig
+        var.targets[0].bone_target = "Camera"
+        var.targets[0].transform_type = 'LOC_' + direction.upper()
+        var.targets[0].transform_space = 'TRANSFORM_SPACE'
+
+    for direction in ('x', 'y'):
+        var = driver.variables.new()
+        var.name = 'res_' + direction
+        var.type = 'SINGLE_PROP'
+        var.targets[0].id_type = 'SCENE'
+        var.targets[0].id = scene
+        var.targets[0].data_path = 'render.resolution_' + direction
+
+    var = driver.variables.new()
+    var.name = 'lens'
+    var.type = 'SINGLE_PROP'
+    var.targets[0].id_type = 'CAMERA'
+    var.targets[0].id = cam.data
+    var.targets[0].data_path = 'lens'
+
+
+def build_camera_rig(context, mode):
+    """Create stuff common to all camera rigs."""
     # Add the camera object
     cam_name = "%s_Camera" % mode.capitalize()
     cam_data = bpy.data.cameras.new(cam_name)
     cam = object_utils.object_data_add(context, cam_data, name=cam_name)
-    view_layer.objects.active = cam
     context.scene.camera = cam
 
-    cam.data.display_size = 1.0
-    cam.rotation_euler[0] = pi / 2.0  # Rotate the camera 90 degrees in x
+    # Add the rig object
+    rig_name = mode.capitalize() + "_Rig"
+    rig_data = bpy.data.armatures.new(rig_name)
+    rig = object_utils.object_data_add(context, rig_data, name=rig_name)
+    rig["rig_id"] = "%s" % rig_name
+    rig.location = context.scene.cursor.location
+
+    bpy.ops.object.mode_set(mode='EDIT')
 
+    # Add new bones and setup specific rigs
+    if mode == "DOLLY":
+        create_dolly_bones(rig)
+        setup_3d_rig(rig, cam)
+    elif mode == "CRANE":
+        create_crane_bones(rig)
+        setup_3d_rig(rig, cam)
+    elif mode == "2D":
+        create_2d_bones(context, rig, cam)
+
+    # Parent the camera to the rig
     cam.location = (0.0, -1.0, 0.0)  # Move the camera to the correct position
     cam.parent = rig
     cam.parent_type = "BONE"
     cam.parent_bone = "Camera"
 
+    # Change display to BBone: it just looks nicer
+    rig.data.display_type = 'BBONE'
+    # Change display to wire for object
+    rig.display_type = 'WIRE'
+
     # Lock camera transforms
     cam.lock_location = (True,) * 3
     cam.lock_rotation = (True,) * 3
     cam.lock_scale = (True,) * 3
 
+    # Add custom properties to the armature’s Camera bone,
+    # so that all properties may be animated in a single action
+
+    pose_bones = rig.pose.bones
+
+    # DOF Focus Distance property
+    pb = pose_bones['Camera']
+    pb["focus_distance"] = 10.0
+    prop = rna_idprop_ui_prop_get(pb, "focus_distance", create=True)
+    prop["default"] = 10.0
+    prop["min"] = 0.0
+
+    # DOF F-Stop property
+    pb = pose_bones['Camera']
+    pb["aperture_fstop"] = 2.8
+    prop = rna_idprop_ui_prop_get(pb, "aperture_fstop", create=True)
+    prop["default"] = 2.8
+    prop["min"] = 0.0
+    prop["soft_min"] = 0.1
+    prop["soft_max"] = 128.0
+
     # Add drivers to link the camera properties to the custom props
     # on the armature
-    for prop_from, prop_to in (("lens", "lens"),
-                               ("focus_distance", "dof.focus_distance"),
-                               ("aperture_fstop", "dof.aperture_fstop")):
-        driver = cam.data.driver_add(prop_to)
-        driver.driver.type = 'SCRIPTED'
-        var = driver.driver.variables.new()
-        var.name = 'var'
-        var.type = 'SINGLE_PROP'
-
-        # Target the custom bone property
-        var.targets[0].id = rig
-        var.targets[0].data_path = 'pose.bones["Camera"]["%s"]' % prop_from
-        driver.driver.expression = 'var'
+    create_prop_driver(rig, cam, "focus_distance", "dof.focus_distance")
+    create_prop_driver(rig, cam, "aperture_fstop", "dof.aperture_fstop")
 
     # Make the rig the active object
-    for ob in view_layer.objects:
-        ob.select_set(False)
+    view_layer = context.view_layer
+    for obj in view_layer.objects:
+        obj.select_set(False)
     rig.select_set(True)
     view_layer.objects.active = rig
 
-    return rig
-
 
 class OBJECT_OT_build_camera_rig(Operator):
     bl_idname = "object.build_camera_rig"
@@ -245,11 +528,12 @@ class OBJECT_OT_build_camera_rig(Operator):
     bl_description = "Build a Camera Rig"
     bl_options = {'REGISTER', 'UNDO'}
 
-    mode: bpy.props.EnumProperty(items=
-                                 (('DOLLY',) * 3,
-                                  ('CRANE',) * 3,),
+    mode: bpy.props.EnumProperty(items=(('DOLLY', 'Dolly', 'Dolly rig'),
+                                        ('CRANE', 'Crane', 'Crane rig',),
+                                        ('2D', '2D', '2D rig')),
                                  name="mode",
-                                 description="", default="DOLLY")
+                                 description="Type of camera to create",
+                                 default="DOLLY")
 
     def execute(self, context):
         # Build the rig
@@ -260,18 +544,23 @@ class OBJECT_OT_build_camera_rig(Operator):
 def add_dolly_crane_buttons(self, context):
     """Dolly and crane entries in the Add Object > Camera Menu"""
     if context.mode == 'OBJECT':
-        op = self.layout.operator(
+        self.layout.operator(
             OBJECT_OT_build_camera_rig.bl_idname,
             text="Dolly Camera Rig",
-            icon='CAMERA_DATA'
-        )
-        op.mode = "DOLLY"
-        op = self.layout.operator(
+            icon='VIEW_CAMERA'
+        ).mode = "DOLLY"
+
+        self.layout.operator(
             OBJECT_OT_build_camera_rig.bl_idname,
             text="Crane Camera Rig",
-            icon='CAMERA_DATA'
-        )
-        op.mode = "CRANE"
+            icon='VIEW_CAMERA'
+        ).mode = "CRANE"
+
+        self.layout.operator(
+            OBJECT_OT_build_camera_rig.bl_idname,
+            text="2D Camera Rig",
+            icon='PIVOT_BOUNDBOX'
+        ).mode = "2D"
 
 
 classes = (
diff --git a/add_camera_rigs/composition_guides_menu.py b/add_camera_rigs/composition_guides_menu.py
index c3ff43e5..16537525 100644
--- a/add_camera_rigs/composition_guides_menu.py
+++ b/add_camera_rigs/composition_guides_menu.py
@@ -19,7 +19,7 @@
 import bpy
 from bpy.types import Panel
 
-from .operators import get_arm_and_cam
+from .operators import get_rig_and_cam
 
 class ADD_CAMERA_RIGS_PT_composition_guides(Panel):
     bl_label = "Composition Guides"
@@ -29,7 +29,7 @@ class ADD_CAMERA_RIGS_PT_composition_guides(Panel):
     def draw(self, context):
         layout = self.layout
 
-        arm, cam = get_arm_and_cam(context.active_object)
+        rig, cam = get_rig_and_cam(context.active_object)
         cam = cam.data
 
         layout.prop(cam, "show_safe_areas")
diff --git a/add_camera_rigs/create_widgets.py b/add_camera_rigs/create_widgets.py
index f19fc206..72a8c70d 100644
--- a/add_camera_rigs/create_widgets.py
+++ b/add_camera_rigs/create_widgets.py
@@ -1,4 +1,24 @@
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
 import bpy
+from mathutils import Vector
+from math import cos, sin, pi
 
 
 def create_widget(name):
@@ -29,6 +49,44 @@ def create_widget(name):
     return obj
 
 
+def create_corner_widget(name, reverse=False):
+    """Create a wedge-shaped widget"""
+    obj = create_widget(name)
+    if not obj.data.vertices:
+        reverse = -1 if reverse else 1
+        verts = (Vector((reverse *  0.0, 0.0, 0.0)),
+                 Vector((reverse *  0.0, 1.0, 0.0)),
+                 Vector((reverse * -0.1, 1.0, 0.0)),
+                 Vector((reverse * -0.1, 0.1, 0.0)),
+                 Vector((reverse * -1.0, 0.1, 0.0)),
+                 Vector((reverse * -1.0, 0.0, 0.0)),
+                 )
+        edges = [(n, (n+1) % len(verts)) for n in range(len(verts))]
+
+        mesh = obj.data
+        mesh.from_pydata(verts, edges, ())
+        mesh.update()
+    return obj
+
+
+def create_circle_widget(name, radius=1.0):
+    """Create a circle-shaped widget"""
+    obj = create_widget(name)
+    if not obj.data.vertices:
+        vert_n = 16
+        verts = []
+        for n in range(vert_n):
+            angle = n / vert_n * 2*pi
+            verts.append(Vector((cos(angle) * radius,
+                                 sin(angle) * radius, 0.0)))
+        edges = [(n, (n+1) % len(verts)) for n in range(len(verts))]
+
+        mesh = obj.data
+        mesh.from_pydata(verts, edges, ())
+        mesh.update()
+    return obj
+
+
 def create_root_widget(name):
     """Create a compass-shaped widget"""
     obj = create_widget(name)
diff --git a/add_camera_rigs/operators.py b/add_camera_rigs/operators.py
index 7468007e..058ed146 100644
--- a/add_camera_rigs/operators.py
+++ b/add_camera_rigs/operators.py
@@ -20,7 +20,7 @@ import bpy
 from bpy.types import Operator
 
 
-def get_arm_and_cam(obj):
+def get_rig_and_cam(obj):
     if obj.type == 'ARMATURE':
         cam = None
         for child in obj.children:
@@ -32,7 +32,8 @@ def get_arm_and_cam(obj):
     elif (obj.type == 'CAMERA'
           and obj.parent is not None
           and "rig_id" in obj.parent
-          and obj.parent["rig_id"].lower() in {"dolly_rig", "crane_rig"}):
+          and obj.parent["rig_id"].lower() in {"dolly_rig",
+                                               "crane_rig", "2d_rig"}):
         return obj.parent, obj
     return None, None
 
@@ -41,25 +42,31 @@ class CameraRigMixin():
     @classmethod
     def poll(cls, context):
         if context.active_object is not None:
-            return get_arm_and_cam(context.active_object) != (None, None)
+            return get_rig_and_cam(context.active_object) != (None, None)
 
         return False
 
 
-class ADD_CAMERA_RIGS_OT_set_scene_camera(Operator, CameraRigMixin):
+class ADD_CAMERA_RIGS_OT_set_scene_camera(Operator):
     bl_idname = "add_camera_rigs.set_scene_camera"
     bl_label = "Make Camera Active"
     bl_description = "Makes the camera parented to this rig the active scene camera"
 
+    @classmethod
+    def poll(cls, context):
+        if context.active_object is not None:
+            rig, cam = get_rig_and_cam(context.active_object)
+            if cam is not None:
+                return cam is not context.scene.camera
+
+        return False
+
     def execute(self, context):
-        arm, cam = get_arm_and_cam(context.active_object)
+        rig, cam = get_rig_and_cam(context.active_object)
         scene_cam = context.scene.camera
 
-        if cam is not None and cam is not scene_cam:
-            context.scene.camera = cam
-            return {'FINISHED'}
-
-        return {'CANCELLED'}
+        context.scene.camera = cam
+        return {'FINISHED'}
 
 
 class ADD_CAMERA_RIGS_OT_add_marker_bind(Operator, CameraRigMixin):
@@ -68,7 +75,7 @@ class ADD_CAMERA_RIGS_OT_add_marker_bind(Operator, CameraRigMixin):
     bl_description = "Add marker to current frame then bind rig camera to it (for camera switching)"
 
     def execute(self, context):
-        arm, cam = get_arm_and_cam(context.active_object)
+        rig, cam = get_rig_and_cam(context.active_object)
 
         marker = context.scene.timeline_markers.new(
             "cam_" + str(context.scene.frame_current),
@@ -85,15 +92,15 @@ class ADD_CAMERA_RIGS_OT_add_dof_object(Operator, CameraRigMixin):
     bl_description = "Create Empty and add as DOF Object"
 
     def execute(self, context):
-        arm, cam = get_arm_and_cam(context.active_object)
-        bone = arm.data.bones['Aim_shape_rotation-MCH']
+        rig, cam = get_rig_and_cam(context.active_object)
+        bone = rig.data.bones['Aim_shape_rotation-MCH']
 
         # Add Empty
         empty_obj = bpy.data.objects.new("EmptyDOF", None)
         context.scene.collection.objects.link(empty_obj)
 
         # Parent to Aim Child bone
-        empty_obj.parent = arm
+        empty_obj.parent = rig
         empty_obj.parent_type = "BONE"
         empty_obj.parent_bone = "Aim_shape_rotation-MCH"
 
diff --git a/add_camera_rigs/ui_panels.py b/add_camera_rigs/ui_panels.py
index 63fe158a..0dc3c69e 100644
--- a/add_camera_rigs/ui_panels.py
+++ b/add_camera_rigs/ui_panels.py
@@ -19,7 +19,7 @@
 import bpy
 from bpy.types import Panel
 
-from .operators import get_arm_and_cam, CameraRigMixin
+from .operators import get_rig_and_cam, CameraRigMixin
 
 
 class ADD_CAMERA_RIGS_PT_camera_rig_ui(Panel, CameraRigMixin):
@@ -30,66 +30,87 @@ class ADD_CAMERA_RIGS_PT_camera_rig_ui(Panel, CameraRigMixin):
 
     def draw(self, context):
         active_object = context.active_object
-        arm, cam = get_arm_and_cam(context.active_object)
-        pose_bones = arm.pose.bones
+        rig, cam = get_rig_and_cam(context.active_object)
+        pose_bones = rig.pose.bones
         cam_data = cam.data
+        layout = self.layout
+
+        # Camera lens
+        if rig["rig_id"].lower() in ("dolly_rig", "crane_rig"):
+            layout.prop(pose_bones["Camera"], '["lens"]',
+                        text="Focal Length (mm)")
+
+        col = layout.column(align=True)
+        col.label(text="Clipping:")
+        col.prop(cam_data, "clip_start", text="Start")
+        col.prop(cam_data, "clip_end", text="End")
 
-        layout = self.layout.box().column()
-        layout.label(text="Clipping:")
-        layout.prop(cam_data, "clip_start", text="Start")
-        layout.prop(cam_data, "clip_end", text="End")
         layout.prop(cam_data, "type")
-        layout.prop(cam_data.dof, "use_dof")
-        if cam_data.dof.use_dof:
-            if cam_data.dof.focus_object is None:
-                layout.operator("add_camera_rigs.add_dof_object",
-                                text="Add DOF Empty", icon="OUTLINER_OB_EMPTY")
-            layout.prop(pose_bones["Camera"],
-                        '["focus_distance"]', text="Focus Distance")
-            layout.prop(pose_bones["Camera"],
-                        '["aperture_fstop"]', text="F-Stop")
 
+        # DoF
+        col = layout.column(align=True)
+        col.prop(cam_data.dof, "use_dof")
+        if cam_data.dof.use_dof:
+            if rig["rig_id"].lower() in ("crane_rig", "dolly_rig"):
+                if cam_data.dof.focus_object is None:
+                    col.operator("add_camera_rigs.add_dof_object",
+                                 text="Add DOF Empty", icon="OUTLINER_OB_EMPTY")
+            else:
+                col.prop(cam_data.dof, "focus_object")
+            row = col.row(align=True)
+            row.active = cam_data.dof.focus_object is None
+            row.prop(pose_bones["Camera"],
+                     '["focus_distance"]', text="Focus Distance")
+            col.prop(pose_bones["Camera"],
+                     '["aperture_fstop"]', text="F-Stop")
+
+        # Viewport display
         layout.prop(active_object, 'show_in_front',
                     toggle=False, text='Show in Front')
         layout.prop(cam_data, "show_limits")
-        layout.prop(cam_data, "show_passepartout")
+        col = layout.column(align=True)
+        col.prop(cam_data, "show_passepartout")
         if cam_data.show_passepartout:
-            layout.prop(cam_data, "passepartout_alpha")
+            col.prop(cam_data, "passepartout_alpha")
 
-        layout.row().separator()
-        # Added the comp guides here
+        # Composition guides
         layout.popover(
             panel="ADD_CAMERA_RIGS_PT_composition_guides",
             text="Composition Guides",)
-        layout.row().separator()
 
-        layout.prop(cam,
+        # Props and operators
+        col = layout.column(align=True)
+        col.prop(cam,
                     "hide_select", text="Make Camera Unselectable")
-
-        layout.operator("add_camera_rigs.add_marker_bind",
-                        text="Add Marker and Bind", icon="MARKER_HLT")
-        if context.scene.camera is not cam:
-            layout.operator("add_camera_rigs.set_scene_camera",
-                            text="Make Camera Active", icon='CAMERA_DATA')
-
-        # Camera lens
-        layout.separator()
-        layout.prop(pose_bones["Camera"], '["lens"]', text="Focal Length (mm)")
-
-        # Track to Constraint
-        layout.label(text="Tracking:")
-        layout.prop(pose_bones["Camera"].constraints["Track To"],
-                    'influence', text="Aim Lock", slider=True)
-
-        if arm["rig_id"].lower() == "crane_rig":
-            col = layout.box().column()
+        col.operator("add_camera_rigs.add_marker_bind",
+                     text="Add Marker and Bind", icon="MARKER_HLT")
+        col.operator("add_camera_rigs.set_scene_camera",
+                     text="Make Camera Active", icon='CAMERA_DATA')
+
+        if rig["rig_id"].lower() in ("dolly_rig", "crane_rig"):
+            # Track to Constraint
+            col = layout.column(align=True)
+            col.label(text="Tracking:")
+            col.prop(pose_bones["Camera"].constraints["Track To"],
+                     'influence', text="Aim Lock", slider=True)
 
             # Crane arm stuff
-            col.label(text="Crane Arm:")
-            col.prop(pose_bones["Crane_height"],
-                     'scale', index=1, text="Arm Height")
-            col.prop(pose_bones["Crane_arm"],
-                     'scale', index=1, text="Arm Length")
+            if rig["rig_id"].lower() == "crane_rig":
+                col = layout.column(align=True)
+                col.label(text="Crane Arm:")
+                col.prop(pose_bones["Crane_height"],
+                         'scale', index=1, text="Arm Height")
+                col.prop(pose_bones["Crane_arm"],
+                         'scale', index=1, text="Arm Length")
+
+        # 2D rig stuff
+        elif rig["rig_id"].lower() == "2d_rig":
+            col = layout.column(align=True)
+            col.label(text="2D Rig:")
+            col.prop(pose_bones["Camera"], '["rotation_shift"]',
+                     text="Rotation/Shift")
+            if cam.data.sensor_width != 36:
+                col.label(text="Please set Camera Sensor Width to 36", icon="ERROR")
 
 
 def register():
diff --git a/add_curve_extra_objects/__init__.py b/add_curve_extra_objects/__init__.py
index 6f4ac24f..407e2fe2 100644
--- a/add_curve_extra_objects/__init__.py
+++ b/add_curve_extra_objects/__init__.py
@@ -16,8 +16,8 @@
 #
 # ##### END GPL LICENSE BLOCK #####
 # Contributed to by:
-# testscreenings, Alejandro Omar Chocano Vasquez, Jimmy Hazevoet, meta-androcto #
-# Cmomoney, Jared Forsyth, Adam Newgas, Spivak Vladimir, Jared Forsyth, Atom    #
+# testscreenings, Alejandro Omar Chocano Vasquez, Jimmy Hazevoet, meta-androcto
+# Cmomoney, Jared Forsyth, Adam Newgas, Spivak Vladimir, Jared Forsyth, Atom
 # Antonio Osprite, Marius Giurgi (DolphinDream)
 
 bl_info = {
@@ -28,8 +28,7 @@ bl_info = {
     "location": "View3D > Add > Curve > Extra Objects",
     "description": "Add extra curve object types",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_curve/extra_objects.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_curve/extra_objects.html",
     "category": "Add Curve",
 }
 
diff --git a/add_curve_ivygen.py b/add_curve_ivygen.py
index 07228e1b..d67225eb 100644
--- a/add_curve_ivygen.py
+++ b/add_curve_ivygen.py
@@ -27,8 +27,7 @@ bl_info = {
     "description": "Adds generated ivy to a mesh object starting "
                    "at the 3D cursor",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_curve/ivy_gen.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_curve/ivy_gen.html",
     "category": "Add Curve",
 }
 
diff --git a/add_curve_sapling/__init__.py b/add_curve_sapling/__init__.py
index 8d607616..b12beada 100644
--- a/add_curve_sapling/__init__.py
+++ b/add_curve_sapling/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "description": ("Adds a parametric tree. The method is presented by "
     "Jason Weber & Joseph Penn in their paper 'Creation and Rendering of "
     "Realistic Trees'"),
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_curve/sapling.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_curve/sapling.html",
     "category": "Add Curve",
 }
 
diff --git a/add_mesh_BoltFactory/__init__.py b/add_mesh_BoltFactory/__init__.py
index d763d13f..34833a49 100644
--- a/add_mesh_BoltFactory/__init__.py
+++ b/add_mesh_BoltFactory/__init__.py
@@ -23,8 +23,7 @@ bl_info = {
     "blender":  (2, 80, 0),
     "location": "View3D > Add > Mesh",
     "description": "Add a bolt or nut",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_mesh/boltfactory.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_mesh/boltfactory.html",
     "category": "Add Mesh",
 }
 
diff --git a/add_mesh_discombobulator/__init__.py b/add_mesh_discombobulator/__init__.py
index b6a6e84a..c1039608 100644
--- a/add_mesh_discombobulator/__init__.py
+++ b/add_mesh_discombobulator/__init__.py
@@ -27,8 +27,7 @@ bl_info = {
     "location": "View3D > Add > Mesh",
     "description": "Add Discombobulator",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_mesh/discombobulator.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_mesh/discombobulator.html",
     "category": "Add Mesh",
 }
 
diff --git a/add_mesh_extra_objects/__init__.py b/add_mesh_extra_objects/__init__.py
index cea0cb2d..4f00c450 100644
--- a/add_mesh_extra_objects/__init__.py
+++ b/add_mesh_extra_objects/__init__.py
@@ -31,8 +31,7 @@ bl_info = {
     "location": "View3D > Add > Mesh",
     "description": "Add extra mesh object types",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_mesh/mesh_extra_objects.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_mesh/mesh_extra_objects.html",
     "category": "Add Mesh",
 }
 
diff --git a/add_mesh_geodesic_domes/__init__.py b/add_mesh_geodesic_domes/__init__.py
index dc153993..c7137614 100644
--- a/add_mesh_geodesic_domes/__init__.py
+++ b/add_mesh_geodesic_domes/__init__.py
@@ -27,8 +27,7 @@ bl_info = {
     "location": "View3D > Add > Mesh",
     "description": "Create geodesic dome type objects.",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_mesh/geodesic_domes.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_mesh/geodesic_domes.html",
     "category": "Add Mesh",
 }
 
diff --git a/animation_add_corrective_shape_key.py b/animation_add_corrective_shape_key.py
index 6faca951..01e13cde 100644
--- a/animation_add_corrective_shape_key.py
+++ b/animation_add_corrective_shape_key.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "Object Data > Shape Keys Specials or Search",
     "description": "Creates a corrective shape key for the current pose",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "animation/corrective_shape_keys.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/animation/corrective_shape_keys.html",
     "category": "Animation",
 }
 
diff --git a/animation_animall.py b/animation_animall.py
index efc4e841..141c032a 100644
--- a/animation_animall.py
+++ b/animation_animall.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "3D View > Toolbox > Animation tab > AnimAll",
     "description": "Allows animation of mesh, lattice, curve and surface data",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "animation/animall.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/animation/animall.html",
     "category": "Animation",
 }
 
diff --git a/ant_landscape/__init__.py b/ant_landscape/__init__.py
index 5af0d261..fa0b7b5a 100644
--- a/ant_landscape/__init__.py
+++ b/ant_landscape/__init__.py
@@ -27,8 +27,7 @@ bl_info = {
     "location": "View3D > Sidebar > Create Tab",
     "description": "Another Noise Tool: Landscape and Displace",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_mesh/ant_landscape.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_mesh/ant_landscape.html",
     "category": "Add Mesh",
 }
 
diff --git a/archimesh/__init__.py b/archimesh/__init__.py
index 10d6c9a6..99692591 100644
--- a/archimesh/__init__.py
+++ b/archimesh/__init__.py
@@ -32,8 +32,7 @@ bl_info = {
     "version": (1, 2, 2),
     "blender": (2, 80, 0),
     "description": "Generate rooms, doors, windows, and other architecture objects",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_mesh/archimesh.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_mesh/archimesh.html",
     "category": "Add Mesh"
     }
 
diff --git a/blender_id/__init__.py b/blender_id/__init__.py
index 9dd8a504..93b09124 100644
--- a/blender_id/__init__.py
+++ b/blender_id/__init__.py
@@ -28,8 +28,7 @@ bl_info = {
     'location': 'Add-on preferences',
     'description':
         'Stores your Blender ID credentials for usage with other add-ons',
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "system/blender_id.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/system/blender_id.html",
     'category': 'System',
     'support': 'OFFICIAL',
 }
diff --git a/blenderkit/__init__.py b/blenderkit/__init__.py
index a45c9b9a..35a5b1ec 100644
--- a/blenderkit/__init__.py
+++ b/blenderkit/__init__.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "View3D > Properties > BlenderKit",
     "description": "Online BlenderKit library (materials, models, brushes and more)",
     "warning": "",
-    "doc_url": "https://youtu.be/1hVgcQhIAo8"
-               "Scripts/Add_Mesh/BlenderKit",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_mesh/blenderkit.html",
     "category": "3D View",
 }
 
diff --git a/bone_selection_sets.py b/bone_selection_sets.py
index 8862244b..8e07f418 100644
--- a/bone_selection_sets.py
+++ b/bone_selection_sets.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "Properties > Object Data (Armature) > Selection Sets",
     "description": "List of Bone sets for easy selection while animating",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "animation/bone_selection_sets.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/animation/bone_selection_sets.html",
     "category": "Animation",
 }
 
diff --git a/btrace/__init__.py b/btrace/__init__.py
index d0f41d5e..aaf0fc15 100644
--- a/btrace/__init__.py
+++ b/btrace/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "location": "View3D > Sidebar > Create Tab",
     "description": "Tools for converting/animating objects/particles into curves",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_curve/btracer.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_curve/btracer.html",
     "category": "Add Curve",
 }
 
diff --git a/camera_turnaround.py b/camera_turnaround.py
index 5742fb79..669fc656 100644
--- a/camera_turnaround.py
+++ b/camera_turnaround.py
@@ -23,8 +23,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "View3D > Sidebar > View Tab > Turnaround Camera",
     "description": "Add a camera rotation around selected object",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "animation/turnaround_camera.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/animation/turnaround_camera.html",
     "category": "Animation",
 }
 
diff --git a/curve_assign_shapekey.py b/curve_assign_shapekey.py
index 7e971035..18e34c0c 100644
--- a/curve_assign_shapekey.py
+++ b/curve_assign_shapekey.py
@@ -27,8 +27,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "View 3D > Sidebar > Edit Tab",
     "description": "Assigns one or more Bezier curves as shape keys to another Bezier curve",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_curve/assign_shape_keys.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_curve/assign_shape_keys.html",
     "category": "Add Curve",
 }
 
diff --git a/curve_simplify.py b/curve_simplify.py
index 85df1dba..0109530a 100644
--- a/curve_simplify.py
+++ b/curve_simplify.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "3D View, Dopesheet & Graph Editors",
     "description": "Simplify Curves: 3dview, Dopesheet, Graph. Distance Merge: 3d view curve edit",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_curve/simplify_curves.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_curve/simplify_curves.html",
     "category": "Add Curve",
 }
 
@@ -597,10 +596,10 @@ def main_rd(context, distance = 0.01):
     if bpy.ops.object.mode_set.poll():
         bpy.ops.object.mode_set(mode='EDIT')
 
-    for curve in selected_Curves:
-        bezier_dellist = []
-        dellist = []
+    bezier_dellist = []
+    dellist = []
 
+    for curve in selected_Curves:
         for spline in curve.data.splines:
             if spline.type == 'BEZIER':
                 if len(spline.bezier_points) > 1:
diff --git a/curve_tools/__init__.py b/curve_tools/__init__.py
index 50641f0a..2fcec1d9 100644
--- a/curve_tools/__init__.py
+++ b/curve_tools/__init__.py
@@ -30,8 +30,7 @@ bl_info = {
     "location": "View3D > Tool Shelf > Edit Tab",
     "warning": "WIP",
     "doc_url": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "add_curve/curve_tools.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/add_curve/curve_tools.html",
     "category": "Add Curve",
 }
 
diff --git a/development_edit_operator.py b/development_edit_operator.py
index 21947f78..f9e0b911 100644
--- a/development_edit_operator.py
+++ b/development_edit_operator.py
@@ -25,8 +25,7 @@ bl_info = {
     "location": "Text Editor > Sidebar > Edit Operator",
     "description": "Opens source file of chosen operator or call locations, if source not available",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "development/edit_operator.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/development/edit_operator.html",
     "category": "Development",
 }
 
diff --git a/development_icon_get.py b/development_icon_get.py
index d2278bed..6e2154ae 100644
--- a/development_icon_get.py
+++ b/development_icon_get.py
@@ -26,8 +26,7 @@ bl_info = {
     "version": (1, 4, 0),
     "blender": (2, 80, 0),
     "location": "Text Editor > Dev Tab > Icon Viewer",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "development/icon_viewer.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/development/icon_viewer.html",
     "category": "Development",
 }
 
diff --git a/development_iskeyfree.py b/development_iskeyfree.py
index 8893eed1..e8215497 100644
--- a/development_iskeyfree.py
+++ b/development_iskeyfree.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "Text Editor > Sidebar > Dev Tab",
     "description": "Find free shortcuts, inform about used and print a key list",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "development/is_key_free.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/development/is_key_free.html",
     "category": "Development",
 }
 
diff --git a/io_anim_bvh/__init__.py b/io_anim_bvh/__init__.py
index 1065b25f..3a17632e 100644
--- a/io_anim_bvh/__init__.py
+++ b/io_anim_bvh/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Import-Export",
     "description": "Import-Export BVH from armature objects",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/anim_bvh.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/anim_bvh.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_anim_camera.py b/io_anim_camera.py
index 24972a5d..6130b552 100644
--- a/io_anim_camera.py
+++ b/io_anim_camera.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Export > Cameras & Markers (.py)",
     "description": "Export Cameras & Markers (.py)",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/anim_camera.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/anim_camera.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_anim_nuke_chan/__init__.py b/io_anim_nuke_chan/__init__.py
index 6c33ff57..3fca3f07 100644
--- a/io_anim_nuke_chan/__init__.py
+++ b/io_anim_nuke_chan/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Import/Export > Nuke (.chan)",
     "description": "Import/Export object's animation with nuke",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/anim_nuke_chan.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/anim_nuke_chan.html",
     "category": "Import-Export",
 }
 
diff --git a/io_coat3D/__init__.py b/io_coat3D/__init__.py
index ea199bea..7275e158 100644
--- a/io_coat3D/__init__.py
+++ b/io_coat3D/__init__.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "Scene > 3D-Coat Applink",
     "description": "Transfer data between 3D-Coat/Blender",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/coat3D.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/coat3D.html",
     "category": "Import-Export",
 }
 
diff --git a/io_curve_svg/__init__.py b/io_curve_svg/__init__.py
index a7a3fe3a..03b1755e 100644
--- a/io_curve_svg/__init__.py
+++ b/io_curve_svg/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "location": "File > Import > Scalable Vector Graphics (.svg)",
     "description": "Import SVG as curves",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/curve_svg.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/curve_svg.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_export_dxf/__init__.py b/io_export_dxf/__init__.py
index e4d035c3..e9083bb5 100644
--- a/io_export_dxf/__init__.py
+++ b/io_export_dxf/__init__.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "File > Export > AutoCAD DXF",
     "description": "The script exports Blender geometry to DXF format r12 version.",
     "warning": "Under construction! Visit Wiki for details.",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/scene_dxf.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/scene_dxf.html",
     "category": "Import-Export",
 }
 
diff --git a/io_export_paper_model.py b/io_export_paper_model.py
index 1329a304..10658dd6 100644
--- a/io_export_paper_model.py
+++ b/io_export_paper_model.py
@@ -17,8 +17,7 @@ bl_info = {
     "location": "File > Export > Paper Model",
     "warning": "",
     "description": "Export printable net of the active mesh",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/paper_model.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/paper_model.html",
     "category": "Import-Export",
 }
 
diff --git a/io_export_pc2.py b/io_export_pc2.py
index b40b2a77..8dda3cd1 100644
--- a/io_export_pc2.py
+++ b/io_export_pc2.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "File > Export > Pointcache (.pc2)",
     "description": "Export mesh Pointcache data (.pc2)",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/pc2.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/pc2.html",
     "category": "Import-Export",
 }
 
diff --git a/io_import_dxf/__init__.py b/io_import_dxf/__init__.py
index bff93e9e..c24f6a82 100644
--- a/io_import_dxf/__init__.py
+++ b/io_import_dxf/__init__.py
@@ -38,8 +38,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "File > Import > AutoCAD DXF",
     "description": "Import files in the Autocad DXF format (.dxf)",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/scene_dxf.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/scene_dxf.html",
     "category": "Import-Export",
 }
 
diff --git a/io_import_images_as_planes.py b/io_import_images_as_planes.py
index dc25bee0..5783d70e 100644
--- a/io_import_images_as_planes.py
+++ b/io_import_images_as_planes.py
@@ -27,8 +27,7 @@ bl_info = {
     "description": "Imports images and creates planes with the appropriate aspect ratio. "
                    "The images are mapped to the planes.",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/images_as_planes.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/images_as_planes.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_import_palette/__init__.py b/io_import_palette/__init__.py
index e8f03185..c2c15d5d 100644
--- a/io_import_palette/__init__.py
+++ b/io_import_palette/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Import",
     "description": "Import Palettes",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/palettes.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/palettes.html",
     "category": "Import-Export",
 }
 
diff --git a/io_mesh_atomic/__init__.py b/io_mesh_atomic/__init__.py
index fd77c31d..81a518b7 100644
--- a/io_mesh_atomic/__init__.py
+++ b/io_mesh_atomic/__init__.py
@@ -63,8 +63,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "File -> Import -> PDB (.pdb) and File -> Import -> XYZ (.xyz)",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/mesh_atomic.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/mesh_atomic.html",
     "category": "Import-Export",
 }
 
diff --git a/io_mesh_ply/__init__.py b/io_mesh_ply/__init__.py
index 86ab7999..5e12bfce 100644
--- a/io_mesh_ply/__init__.py
+++ b/io_mesh_ply/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 82, 0),
     "location": "File > Import-Export",
     "description": "Import-Export PLY mesh data with UVs and vertex colors",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/mesh_ply.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/mesh_ply.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_mesh_stl/__init__.py b/io_mesh_stl/__init__.py
index 17af58f1..7af1c2d1 100644
--- a/io_mesh_stl/__init__.py
+++ b/io_mesh_stl/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 81, 6),
     "location": "File > Import-Export",
     "description": "Import-Export STL files",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/mesh_stl.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/mesh_stl.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_mesh_uv_layout/__init__.py b/io_mesh_uv_layout/__init__.py
index b376fda4..21b68c65 100644
--- a/io_mesh_uv_layout/__init__.py
+++ b/io_mesh_uv_layout/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "Image-Window > UVs > Export UV Layout",
     "description": "Export the UV layout as a 2D graphic",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/mesh_uv_layout.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/mesh_uv_layout.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_scene_fbx/__init__.py b/io_scene_fbx/__init__.py
index dcffe3ab..40ca5fc4 100644
--- a/io_scene_fbx/__init__.py
+++ b/io_scene_fbx/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Import-Export",
     "description": "FBX IO meshes, UV's, vertex colors, materials, textures, cameras, lamps and actions",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/scene_fbx.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/scene_fbx.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_scene_gltf2/__init__.py b/io_scene_gltf2/__init__.py
index de7bbe7a..49f6f470 100755
--- a/io_scene_gltf2/__init__.py
+++ b/io_scene_gltf2/__init__.py
@@ -15,12 +15,12 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 2, 35),
+    "version": (1, 2, 38),
     'blender': (2, 82, 7),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',
     'warning': '',
-    'doc_url': "https://docs.blender.org/manual/en/dev/addons/import_export/scene_gltf2.html",
+    'doc_url': "{BLENDER_MANUAL_URL}/addons/import_export/scene_gltf2.html",
     'tracker_url': "https://github.com/KhronosGroup/glTF-Blender-IO/issues/",
     'support': 'OFFICIAL',
     'category': 'Import-Export',
@@ -856,11 +856,26 @@ class ImportGLTF2(Operator, ImportHelper):
         description="How normals are computed during import",
         default="NORMALS")
 
+    bone_heuristic: EnumProperty(
+        name="Bone Dir",
+        items=(
+            ("BLENDER", "Blender (+Y)",
+                "Round-trips bone directions in glTFs exported from Blender.\n"
+                "Bone tips are placed on their local +Y axis (in glTF space)"),
+            ("TEMPERANCE", "Temperance",
+                "Okay for many different models.\n"
+                "Bone tips are placed at a child's root")
+        ),
+        description="Heuristic for placing bones. Tries to make bones pretty",
+        default="TEMPERANCE",
+    )
+
     def draw(self, context):
         layout = self.layout
 
         layout.prop(self, 'import_pack_images')
         layout.prop(self, 'import_shading')
+        layout.prop(self, 'bone_heuristic')
 
     def execute(self, context):
         return self.import_gltf2(context)
diff --git a/io_scene_gltf2/blender/com/gltf2_blender_math.py b/io_scene_gltf2/blender/com/gltf2_blender_math.py
index fb342bc4..b3f13f65 100755
--- a/io_scene_gltf2/blender/com/gltf2_blender_math.py
+++ b/io_scene_gltf2/blender/com/gltf2_blender_math.py
@@ -170,3 +170,45 @@ def transform_value(value: Vector, _: Matrix = Matrix.Identity(4)) -> Vector:
 def round_if_near(value: float, target: float) -> float:
     """If value is very close to target, round to target."""
     return value if abs(value - target) > 2.0e-6 else target
+
+def scale_rot_swap_matrix(rot):
+    """Returns a matrix m st. Scale[s] Rot[rot] = Rot[rot] Scale[m s].
+    If rot.to_matrix() is a signed permutation matrix, works for any s.
+    Otherwise works only if s is a uniform scaling.
+    """
+    m = nearby_signed_perm_matrix(rot)  # snap to signed perm matrix
+    m.transpose()  # invert permutation
+    for i in range(3):
+        for j in range(3):
+            m[i][j] = abs(m[i][j])  # discard sign
+    return m
+
+def nearby_signed_perm_matrix(rot):
+    """Returns a signed permutation matrix close to rot.to_matrix().
+    (A signed permutation matrix is like a permutation matrix, except
+    the non-zero entries can be ±1.)
+    """
+    m = rot.to_matrix()
+    x, y, z = m[0], m[1], m[2]
+
+    # Set the largest entry in the first row to ±1
+    a, b, c = abs(x[0]), abs(x[1]), abs(x[2])
+    i = 0 if a >= b and a >= c else 1 if b >= c else 2
+    x[i] = 1 if x[i] > 0 else -1
+    x[(i+1) % 3] = 0
+    x[(i+2) % 3] = 0
+
+    # Same for second row: only two columns to consider now.
+    a, b = abs(y[(i+1) % 3]), abs(y[(i+2) % 3])
+    j = (i+1) % 3 if a >= b else (i+2) % 3
+    y[j] = 1 if y[j] > 0 else -1
+    y[(j+1) % 3] = 0
+    y[(j+2) % 3] = 0
+
+    # Same for third row: only one column left
+    k = (0 + 1 + 2) - i - j
+    z[k] = 1 if z[k] > 0 else -1
+    z[(k+1) % 3] = 0
+    z[(k+2) % 3] = 0
+
+    return m
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py
index 1e155ffd..7194798f 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_mesh.py
@@ -39,8 +39,8 @@ def gather_mesh(blender_mesh: bpy.types.Mesh,
         extensions=__gather_extensions(blender_mesh, vertex_groups, modifiers, export_settings),
         extras=__gather_extras(blender_mesh, vertex_groups, modifiers, export_settings),
         name=__gather_name(blender_mesh, vertex_groups, modifiers, export_settings),
+        weights=__gather_weights(blender_mesh, vertex_groups, modifiers, export_settings),
         primitives=__gather_primitives(blender_mesh, blender_object, vertex_groups, modifiers, material_names, export_settings),
-        weights=__gather_weights(blender_mesh, vertex_groups, modifiers, export_settings)
     )
 
     if len(mesh.primitives) == 0:
@@ -134,15 +134,6 @@ def __gather_weights(blender_mesh: bpy.types.Mesh,
                      modifiers: Optional[bpy.types.ObjectModifiers],
                      export_settings
                      ) -> Optional[List[float]]:
-
-    # Seems that in some files, when using Apply Modifier, shape_keys return an error
-    # ReferenceError: StructRNA of type Mesh has been removed
-    # Because shapekeys are not exported in that case, we can return None
-    try:
-        blender_mesh.shape_keys
-    except:
-        return None
-
     if not export_settings[MORPH] or not blender_mesh.shape_keys:
         return None
 
diff --git a/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py b/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
index db1115d0..cca86432 100755
--- a/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
+++ b/io_scene_gltf2/blender/exp/gltf2_blender_gather_primitives.py
@@ -59,6 +59,8 @@ def gather_primitives(
             material = gltf2_blender_gather_materials.gather_material(blender_material,
                                                                   double_sided,
                                                                   export_settings)
+            # NOTE: gather_material may invalidate blender_mesh (see #932),
+            # so make sure not to access blender_mesh again after this point
         except IndexError:
             # no material at that index
             pass
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_animation_bone.py b/io_scene_gltf2/blender/imp/gltf2_blender_animation_bone.py
index 62c179c1..6f65de43 100755
--- a/io_scene_gltf2/blender/imp/gltf2_blender_animation_bone.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_animation_bone.py
@@ -58,12 +58,14 @@ class BlenderBoneAnim():
         else:
             translation_keyframes = (gltf.loc_gltf_to_blender(vals) for vals in values)
 
+        final_translations = vnode.base_locs_to_final_locs(translation_keyframes)
+
         # Calculate pose bone trans from final bone trans
         edit_trans, edit_rot = vnode.editbone_trans, vnode.editbone_rot
         edit_rot_inv = edit_rot.conjugated()
         pose_translations = [
             edit_rot_inv @ (trans - edit_trans)
-            for trans in translation_keyframes
+            for trans in final_translations
         ]
 
         BlenderBoneAnim.fill_fcurves(
@@ -93,12 +95,14 @@ class BlenderBoneAnim():
         else:
             quat_keyframes = [gltf.quaternion_gltf_to_blender(vals) for vals in values]
 
+        final_rots = vnode.base_rots_to_final_rots(quat_keyframes)
+
         # Calculate pose bone rotation from final bone rotation
         edit_rot = vnode.editbone_rot
         edit_rot_inv = edit_rot.conjugated()
         pose_rots = [
             edit_rot_inv @ rot
-            for rot in quat_keyframes
+            for rot in final_rots
         ]
 
         # Manage antipodal quaternions
@@ -133,10 +137,13 @@ class BlenderBoneAnim():
         else:
             scale_keyframes = [gltf.scale_gltf_to_blender(vals) for vals in values]
 
+        final_scales = vnode.base_scales_to_final_scales(scale_keyframes)
+        pose_scales = final_scales  # no change needed
+
         BlenderBoneAnim.fill_fcurves(
             obj.animation_data.action,
             keys,
-            scale_keyframes,
+            pose_scales,
             group_name,
             blender_path,
             animation.samplers[channel.sampler].interpolation
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_animation_node.py b/io_scene_gltf2/blender/imp/gltf2_blender_animation_node.py
index a0205483..b6369b8b 100755
--- a/io_scene_gltf2/blender/imp/gltf2_blender_animation_node.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_animation_node.py
@@ -74,20 +74,22 @@ class BlenderNodeAnim():
                 blender_path = "location"
                 group_name = "Location"
                 num_components = 3
+                values = [gltf.loc_gltf_to_blender(vals) for vals in values]
+                values = vnode.base_locs_to_final_locs(values)
 
                 if vnode.parent is not None and gltf.vnodes[vnode.parent].type == VNode.Bone:
                     # Nodes with a bone parent need to be translated
-                    # backwards by their bone length (always 1 currently)
-                    off = Vector((0, -1, 0))
-                    values = [gltf.loc_gltf_to_blender(vals) + off for vals in values]
-                else:
-                    values = [gltf.loc_gltf_to_blender(vals) for vals in values]
+                    # backwards from the tip to the root
+                    bone_length = gltf.vnodes[vnode.parent].bone_length
+                    off = Vector((0, -bone_length, 0))
+                    values = [vals + off for vals in values]
 
             elif channel.target.path == "rotation":
                 blender_path = "rotation_quaternion"
                 group_name = "Rotation"
                 num_components = 4
                 values = [gltf.quaternion_gltf_to_blender(vals) for vals in values]
+                values = vnode.base_rots_to_final_rots(values)
 
                 # Manage antipodal quaternions
                 for i in range(1, len(values)):
@@ -99,6 +101,7 @@ class BlenderNodeAnim():
                 group_name = "Scale"
                 num_components = 3
                 values = [gltf.scale_gltf_to_blender(vals) for vals in values]
+                values = vnode.base_scales_to_final_scales(values)
 
             coords = [0] * (2 * len(keys))
             coords[::2] = (key[0] * fps for key in keys)
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_gltf.py b/io_scene_gltf2/blender/imp/gltf2_blender_gltf.py
index 8e6c1950..e00e2449 100755
--- a/io_scene_gltf2/blender/imp/gltf2_blender_gltf.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_gltf.py
@@ -24,7 +24,26 @@ class BlenderGlTF():
 
     @staticmethod
     def create(gltf):
-        """Create glTF main method."""
+        """Create glTF main method, with optional profiling"""
+        profile = bpy.app.debug_value == 102
+        if profile:
+            import cProfile, pstats, io
+            from pstats import SortKey
+            pr = cProfile.Profile()
+            pr.enable()
+            BlenderGlTF._create(gltf)
+            pr.disable()
+            s = io.StringIO()
+            sortby = SortKey.TIME
+            ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
+            ps.print_stats()
+            print(s.getvalue())
+        else:
+            BlenderGlTF._create(gltf)
+
+    @staticmethod
+    def _create(gltf):
+        """Create glTF main worker method."""
         BlenderGlTF.set_convert_functions(gltf)
         BlenderGlTF.pre_compute(gltf)
         BlenderScene.create(gltf)
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_node.py b/io_scene_gltf2/blender/imp/gltf2_blender_node.py
index d1ffdbe9..6ce91ea3 100755
--- a/io_scene_gltf2/blender/imp/gltf2_blender_node.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_node.py
@@ -78,7 +78,7 @@ class BlenderNode():
             set_extras(obj, pynode.extras)
 
         # Set transform
-        trans, rot, scale = vnode.trs
+        trans, rot, scale = vnode.trs()
         obj.location = trans
         obj.rotation_mode = 'QUATERNION'
         obj.rotation_quaternion = rot
@@ -96,8 +96,8 @@ class BlenderNode():
                 obj.parent_bone = parent_vnode.blender_bone_name
 
                 # Nodes with a bone parent need to be translated
-                # backwards by their bone length (always 1 currently)
-                obj.location += Vector((0, -1, 0))
+                # backwards from the tip to the root
+                obj.location += Vector((0, -parent_vnode.bone_length, 0))
 
         bpy.data.scenes[gltf.blender_scene].collection.objects.link(obj)
 
@@ -138,6 +138,7 @@ class BlenderNode():
             editbone.head = arma_mat @ Vector((0, 0, 0))
             editbone.tail = arma_mat @ Vector((0, 1, 0))
             editbone.align_roll(arma_mat @ Vector((0, 0, 1)) - editbone.head)
+            editbone.length = vnode.bone_length
 
             if isinstance(id, int):
                 pynode = gltf.data.nodes[id]
@@ -161,7 +162,7 @@ class BlenderNode():
 
             # BoneTRS = EditBone * PoseBone
             # Set PoseBone to make BoneTRS = vnode.trs.
-            t, r, s = vnode.trs
+            t, r, s = vnode.trs()
             et, er = vnode.editbone_trans, vnode.editbone_rot
             pose_bone.location = er.conjugated() @ (t - et)
             pose_bone.rotation_mode = 'QUATERNION'
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py b/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py
index 07030a62..a4df6f3f 100755
--- a/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py
@@ -14,6 +14,8 @@
 
 import bpy
 from mathutils import Vector, Matrix
+import numpy as np
+# import time
 
 from .gltf2_blender_material import BlenderMaterial
 from ...io.imp.gltf2_io_binary import BinaryData
@@ -194,20 +196,27 @@ class BlenderPrimitive():
             layer_name = 'Col' if set_num == 0 else 'Col.%03d' % set_num
             layer = BlenderPrimitive.get_layer(bme.loops.layers.color, layer_name)
 
-            colors = BinaryData.get_data_from_accessor(gltf, attributes['COLOR_%d' % set_num], cache=True)
+            # colors is a 2d array: [N][3 or 4]
+            gltf_attr_name = 'COLOR_%d' % set_num
+            colors_raw = BinaryData.get_data_from_accessor(gltf, attributes[gltf_attr_name], cache=True)
+            colors = np.array(colors_raw, dtype=np.float32)
 
             is_rgba = len(colors[0]) == 4
-
+            if not is_rgba:
+                # RGB -> RGBA
+                ones = np.ones((colors.shape[0], 1))
+                colors = np.concatenate((colors, ones), axis=1) # add alpha channel
+
+            srgb_colors = color_linear_to_srgb(colors)
+            # t = time.perf_counter()
+            # This needs to be a tight loop because it runs over all vertices,
+            # which is why this code looks a little odd.
             for bidx, pidx in vert_idxs:
-                color = colors[pidx]
-                col = (
-                    color_linear_to_srgb(color[0]),
-                    color_linear_to_srgb(color[1]),
-                    color_linear_to_srgb(color[2]),
-                    color[3] if is_rgba else 1.0,
-                )
+                color = srgb_colors[pidx]
+                col = (color[0], color[1], color[2], color[3]) # fastest this way
                 for loop in bme_verts[bidx].link_loops:
                     loop[layer] = col
+            # print(f'store colors: {time.perf_counter() - t}')
 
             set_num += 1
 
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_vnode.py b/io_scene_gltf2/blender/imp/gltf2_blender_vnode.py
index bd5edcd1..554c09e9 100644
--- a/io_scene_gltf2/blender/imp/gltf2_blender_vnode.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_vnode.py
@@ -15,6 +15,8 @@
 import bpy
 from mathutils import Vector, Quaternion, Matrix
 
+from ..com.gltf2_blender_math import scale_rot_swap_matrix, nearby_signed_perm_matrix
+
 def compute_vnodes(gltf):
     """Computes the tree of virtual nodes.
     Copies the glTF nodes into a tree of VNodes, then performs a series of
@@ -26,6 +28,7 @@ def compute_vnodes(gltf):
     fixup_multitype_nodes(gltf)
     correct_cameras_and_lights(gltf)
     pick_bind_pose(gltf)
+    prettify_bones(gltf)
     calc_bone_matrices(gltf)
 
 
@@ -45,17 +48,60 @@ class VNode:
         self.parent = None
         self.type = VNode.Object
         self.is_arma = False
-        self.trs = (
+        self.base_trs = (
             Vector((0, 0, 0)),
             Quaternion((1, 0, 0, 0)),
             Vector((1, 1, 1)),
         )
+        # Additional rotations before/after the base TRS.
+        # Allows per-vnode axis adjustment. See local_rotation.
+        self.rotation_after = Quaternion((1, 0, 0, 0))
+        self.rotation_before = Quaternion((1, 0, 0, 0))
+
         # Indices of the glTF node where the mesh, etc. came from.
         # (They can get moved around.)
         self.mesh_node_idx = None
         self.camera_node_idx = None
         self.light_node_idx = None
 
+    def trs(self):
+        # (final TRS) = (rotation after) (base TRS) (rotation before)
+        t, r, s = self.base_trs
+        m = scale_rot_swap_matrix(self.rotation_before)
+        return (
+            self.rotation_after @ t,
+            self.rotation_after @ r @ self.rotation_before,
+            m @ s,
+        )
+
+    def base_locs_to_final_locs(self, base_locs):
+        ra = self.rotation_after
+        return [ra @ loc for loc in base_locs]
+
+    def base_rots_to_final_rots(self, base_rots):
+        ra, rb = self.rotation_after, self.rotation_before
+        return [ra @ rot @ rb for rot in base_rots]
+
+    def base_scales_to_final_scales(self, base_scales):
+        m = scale_rot_swap_matrix(self.rotation_before)
+        return [m @ scale for scale in base_scales]
+
+def local_rotation(gltf, vnode_id, rot):
+    """Appends a local rotation to vnode's world transform:
+    (new world transform) = (old world transform) @ (rot)
+    without changing the world transform of vnode's children.
+
+    For correctness, rot must be a signed permutation of the axes
+    (eg. (X Y Z)->(X -Z Y)) OR vnode's scale must always be uniform.
+    """
+    gltf.vnodes[vnode_id].rotation_before @= rot
+
+    # Append the inverse rotation after children's TRS to cancel it out.
+    rot_inv = rot.conjugated()
+    for child in gltf.vnodes[vnode_id].children:
+        gltf.vnodes[child].rotation_after = \
+            rot_inv @ gltf.vnodes[child].rotation_after
+
 
 def init_vnodes(gltf):
     # Map of all VNodes. The keys are arbitrary IDs.
@@ -67,7 +113,7 @@ def init_vnodes(gltf):
         gltf.vnodes[i] = vnode
         vnode.name = pynode.name or 'Node_%d' % i
         vnode.children = list(pynode.children or [])
-        vnode.trs = get_node_trs(gltf, pynode)
+        vnode.base_trs = get_node_trs(gltf, pynode)
         if pynode.mesh is not None:
             vnode.mesh_node_idx = i
         if pynode.camera is not None:
@@ -216,7 +262,7 @@ def move_skinned_meshes(gltf):
         )
         if ok_to_move:
             reparent(gltf, id, new_parent=arma)
-            vnode.trs = (
+            vnode.base_trs = (
                 Vector((0, 0, 0)),
                 Quaternion((1, 0, 0, 0)),
                 Vector((1, 1, 1)),
@@ -304,35 +350,13 @@ def correct_cameras_and_lights(gltf):
     if gltf.camera_correction is None:
         return
 
-    trs = (Vector((0, 0, 0)), gltf.camera_correction, Vector((1, 1, 1)))
-
-    ids = list(gltf.vnodes.keys())
-    for id in ids:
-        vnode = gltf.vnodes[id]
-
-        # Move the camera/light onto a new child and set its rotation
-        # TODO: "hard apply" the rotation without creating a new node
-        #       (like we'll need to do for bones)
+    for id, vnode in gltf.vnodes.items():
+        needs_correction = \
+           vnode.camera_node_idx is not None or \
+           vnode.light_node_idx is not None
 
-        if vnode.camera_node_idx is not None:
-            new_id = str(id) + '.camera-correction'
-            gltf.vnodes[new_id] = VNode()
-            gltf.vnodes[new_id].name = vnode.name + ' Correction'
-            gltf.vnodes[new_id].trs = trs
-            gltf.vnodes[new_id].camera_node_idx = vnode.camera_node_idx
-            gltf.vnodes[new_id].parent = id
-            vnode.children.append(new_id)
-            vnode.camera_node_idx = None
-
-        if vnode.light_node_idx is not None:
-            new_id = str(id) + '.light-correction'
-            gltf.vnodes[new_id] = VNode()
-            gltf.vnodes[new_id].name = vnode.name + ' Correction'
-            gltf.vnodes[new_id].trs = trs
-            gltf.vnodes[new_id].light_node_idx = vnode.light_node_idx
-            gltf.vnodes[new_id].parent = id
-            vnode.children.append(new_id)
-            vnode.light_node_idx = None
+        if needs_correction:
+            local_rotation(gltf, id, gltf.camera_correction)
 
 
 def pick_bind_pose(gltf):
@@ -345,14 +369,102 @@ def pick_bind_pose(gltf):
         if vnode.type == VNode.Bone:
             # For now, use the node TR for bind pose.
             # TODO: try calculating from inverseBindMatices?
-            vnode.bind_trans = Vector(vnode.trs[0])
-            vnode.bind_rot = Quaternion(vnode.trs[1])
+            vnode.bind_trans = Vector(vnode.base_trs[0])
+            vnode.bind_rot = Quaternion(vnode.base_trs[1])
 
             # Initialize editbones to match bind pose
             vnode.editbone_trans = Vector(vnode.bind_trans)
             vnode.editbone_rot = Quaternion(vnode.bind_rot)
 
 
+def prettify_bones(gltf):
+    """
+    Prettify bone lengths/directions.
+    """
+    def visit(vnode_id, parent_rot=None):  # Depth-first walk
+        vnode = gltf.vnodes[vnode_id]
+        rot = None
+
+        if vnode.type == VNode.Bone:
+            vnode.bone_length = pick_bone_length(gltf, vnode_id)
+            rot = pick_bone_rotation(gltf, vnode_id, parent_rot)
+            if rot is not None:
+                rotate_edit_bone(gltf, vnode_id, rot)
+
+        for child in vnode.children:
+            visit(child, parent_rot=rot)
+
+    visit('root')
+
+MIN_BONE_LENGTH = 0.004  # too small and bones get deleted
+
+def pick_bone_length(gltf, bone_id):
+    """Heuristic for bone length."""
+    vnode = gltf.vnodes[bone_id]
+
+    child_locs = [
+        gltf.vnodes[child].editbone_trans
+        for child in vnode.children
+        if gltf.vnodes[child].type == VNode.Bone
+    ]
+    child_locs = [loc for loc in child_locs if loc.length > MIN_BONE_LENGTH]
+    if child_locs:
+        return min(loc.length for loc in child_locs)
+
+    if gltf.vnodes[vnode.parent].type == VNode.Bone:
+        return gltf.vnodes[vnode.parent].bone_length
+
+    if vnode.editbone_trans.length > MIN_BONE_LENGTH:
+        return vnode.editbone_trans.length
+
+    return 1
+
+def pick_bone_rotation(gltf, bone_id, parent_rot):
+    """Heuristic for bone rotation.
+    A bone's tip lies on its local +Y axis so rotating a bone let's us
+    adjust the bone direction.
+    """
+    if bpy.app.debug_value == 100:
+        return None
+
+    if gltf.import_settings['bone_heuristic'] == 'BLENDER':
+        return Quaternion((2**0.5/2, 2**0.5/2, 0, 0))
+    elif gltf.import_settings['bone_heuristic'] == 'TEMPERANCE':
+        return temperance(gltf, bone_id, parent_rot)
+
+def temperance(gltf, bone_id, parent_rot):
+    vnode = gltf.vnodes[bone_id]
+
+    # Try to put our tip at the centroid of our children
+    child_locs = [
+        gltf.vnodes[child].editbone_trans
+        for child in vnode.children
+        if gltf.vnodes[child].type == VNode.Bone
+    ]
+    child_locs = [loc for loc in child_locs if loc.length > MIN_BONE_LENGTH]
+    if child_locs:
+        centroid = sum(child_locs, Vector((0, 0, 0)))
+        rot = Vector((0, 1, 0)).rotation_difference(centroid)
+        rot = nearby_signed_perm_matrix(rot).to_quaternion()
+        return rot
+
+    return parent_rot
+
+def rotate_edit_bone(gltf, bone_id, rot):
+    """Rotate one edit bone without affecting anything else."""
+    gltf.vnodes[bone_id].editbone_rot @= rot
+    # Cancel out the rotation so children aren't affected.
+    rot_inv = rot.conjugated()
+    for child_id in gltf.vnodes[bone_id].children:
+        child = gltf.vnodes[child_id]
+        if child.type == VNode.Bone:
+            child.editbone_trans = rot_inv @ child.editbone_trans
+            child.editbone_rot = rot_inv @ child.editbone_rot
+    # Need to rotate the bone's final TRS by the same amount so skinning
+    # isn't affected.
+    local_rotation(gltf, bone_id, rot)
+
+
 def calc_bone_matrices(gltf):
     """
     Calculate the transformations from bone space to arma space in the bind
@@ -380,6 +492,3 @@ def calc_bone_matrices(gltf):
             visit(child)
 
     visit('root')
-
-
-# TODO: add pass to rotate/resize bones so they look pretty
diff --git a/io_scene_gltf2/io/com/gltf2_io_color_management.py b/io_scene_gltf2/io/com/gltf2_io_color_management.py
index 56b3a246..58dc3a27 100644
--- a/io_scene_gltf2/io/com/gltf2_io_color_management.py
+++ b/io_scene_gltf2/io/com/gltf2_io_color_management.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import numpy as np
 
 def color_srgb_to_scene_linear(c):
     """
@@ -29,8 +30,27 @@ def color_linear_to_srgb(c):
     Convert from linear to sRGB color space.
 
     Source: Cycles addon implementation, node_color.h.
+    c may be a single color value or an array.
+
+    If c's last dimension is 4, it's assumed to be RGBA and the
+    alpha channel is not converted.
     """
-    if c < 0.0031308:
-        return 0.0 if c < 0.0 else c * 12.92
+    if type(c) in (list, np.ndarray):
+        colors = np.array(c, np.float32) if type(c) == list else c
+        if  colors.ndim > 1 and colors.shape[-1] == 4:
+            colors_noa = colors[..., 0:3] # only process RGB for speed
+        else:
+            colors_noa = colors
+        not_small = colors_noa >= 0.0031308
+        small_result = np.where(colors_noa < 0.0, 0.0, colors_noa * 12.92)
+        large_result = 1.055 * np.power(colors_noa, 1.0 / 2.4, where=not_small) - 0.055
+        result = np.where(not_small, large_result, small_result)
+        if  colors.ndim > 1 and colors.shape[-1] == 4:
+            # copy alpha from original
+            result = np.concatenate((result, colors[..., 3, np.newaxis]), axis=-1)
+        return result
     else:
-        return 1.055 * pow(c, 1.0 / 2.4) - 0.055
+        if c < 0.0031308:
+            return 0.0 if c < 0.0 else c * 12.92
+        else:
+            return 1.055 * pow(c, 1.0 / 2.4) - 0.055
diff --git a/io_scene_obj/__init__.py b/io_scene_obj/__init__.py
index 7cd0f72f..997deee2 100644
--- a/io_scene_obj/__init__.py
+++ b/io_scene_obj/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Import-Export",
     "description": "Import-Export OBJ, Import OBJ mesh, UV's, materials and textures",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/scene_obj.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/scene_obj.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/io_scene_x3d/__init__.py b/io_scene_x3d/__init__.py
index 232ee479..ba355d08 100644
--- a/io_scene_x3d/__init__.py
+++ b/io_scene_x3d/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Import-Export",
     "description": "Import-Export X3D, Import VRML2",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/scene_x3d.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/scene_x3d.html",
     "category": "Import-Export",
 }
 
diff --git a/io_shape_mdd/__init__.py b/io_shape_mdd/__init__.py
index 0078b537..fa59fe0d 100644
--- a/io_shape_mdd/__init__.py
+++ b/io_shape_mdd/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "File > Import-Export",
     "description": "Import-Export MDD as mesh shape keys",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "import_export/shape_mdd.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/import_export/shape_mdd.html",
     "support": 'OFFICIAL',
     "category": "Import-Export",
 }
diff --git a/lighting_dynamic_sky.py b/lighting_dynamic_sky.py
index 86fa6c06..1b22a3a4 100644
--- a/lighting_dynamic_sky.py
+++ b/lighting_dynamic_sky.py
@@ -27,8 +27,7 @@ bl_info = {
     "location": "View3D > Sidebar > Create Tab",
     "description": "Creates Dynamic Sky for Cycles",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "lighting/dynamic_sky.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/lighting/dynamic_sky.html",
     "category": "Lighting",
 }
 
diff --git a/lighting_tri_lights.py b/lighting_tri_lights.py
index 3e864694..a5478974 100644
--- a/lighting_tri_lights.py
+++ b/lighting_tri_lights.py
@@ -9,8 +9,7 @@ bl_info = {
     "description": "Add 3 Point Lighting to Selected / Active Object",
     "warning": "",
     "tracker_url": "https://developer.blender.org/maniphest/task/edit/form/2/",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "lighting/trilighting.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/lighting/trilighting.html",
     "category": "Lighting",
 }
 
diff --git a/magic_uv/__init__.py b/magic_uv/__init__.py
index c1b78e40..8630038a 100644
--- a/magic_uv/__init__.py
+++ b/magic_uv/__init__.py
@@ -35,8 +35,7 @@ bl_info = {
     "description": "UV Toolset. See Add-ons Preferences for details",
     "warning": "",
     "support": "COMMUNITY",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "uv/magic_uv.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/uv/magic_uv.html",
     "tracker_url": "https://github.com/nutti/Magic-UV",
     "category": "UV",
 }
diff --git a/materials_library_vx/__init__.py b/materials_library_vx/__init__.py
index eaed03de..d03afeaa 100644
--- a/materials_library_vx/__init__.py
+++ b/materials_library_vx/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "Properties > Material",
     "description": "Material Library VX",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "materials/material_library.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/materials/material_library.html",
     "tracker_url": "",
     "category": "Material",
 }
diff --git a/materials_utils/__init__.py b/materials_utils/__init__.py
index 9223ac72..84b10fc1 100644
--- a/materials_utils/__init__.py
+++ b/materials_utils/__init__.py
@@ -40,8 +40,7 @@ bl_info = {
     "location": "View3D > Shift + Q key",
     "description": "Menu of material tools (assign, select..) in the 3D View",
     "warning": "Beta",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "materials/material_utils.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/materials/material_utils.html",
    "category": "Material"
 }
 
diff --git a/measureit/__init__.py b/measureit/__init__.py
index 79e41589..82e00589 100644
--- a/measureit/__init__.py
+++ b/measureit/__init__.py
@@ -32,7 +32,7 @@ bl_info = {
     "version": (1, 8, 1),
     "blender": (2, 80, 0),
     "description": "Tools for measuring objects.",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons"
+    "doc_url": "{BLENDER_MANUAL_URL}/addons"
                "/3d_view/measureit.html",
     "category": "3D View"
 }
diff --git a/mesh_auto_mirror.py b/mesh_auto_mirror.py
index 8359e58e..8c21ccfa 100644
--- a/mesh_auto_mirror.py
+++ b/mesh_auto_mirror.py
@@ -14,8 +14,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "View 3D > Sidebar > Edit Tab > AutoMirror (panel)",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "mesh/auto_mirror.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/mesh/auto_mirror.html",
     "category": "Mesh",
 }
 
diff --git a/mesh_bsurfaces.py b/mesh_bsurfaces.py
index f1ae463e..705776d3 100644
--- a/mesh_bsurfaces.py
+++ b/mesh_bsurfaces.py
@@ -24,8 +24,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "View3D EditMode > Sidebar > Edit Tab",
     "description": "Modeling and retopology tool",
-    "doc_url": "https://docs.blender.org/manual/nb/dev/addons/"
-               "mesh/bsurfaces.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/mesh/bsurfaces.html",
     "category": "Mesh",
 }
 
diff --git a/mesh_f2.py b/mesh_f2.py
index dcea9d38..569b86de 100644
--- a/mesh_f2.py
+++ b/mesh_f2.py
@@ -29,8 +29,7 @@ bl_info = {
     "location": "Editmode > F",
     "warning": "",
     "description": "Extends the 'Make Edge/Face' functionality",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "mesh/f2.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/mesh/f2.html",
     "category": "Mesh",
 }
 
diff --git a/mesh_inset/__init__.py b/mesh_inset/__init__.py
index 4dbd8472..74148dfe 100644
--- a/mesh_inset/__init__.py
+++ b/mesh_inset/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "3DView Operator",
     "description": "Make an inset inside selection using straight skeleton algorithm.",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "mesh/inset_straight_skeleton.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/mesh/inset_straight_skeleton.html",
     "category": "Mesh",
 }
 
diff --git a/mesh_looptools.py b/mesh_looptools.py
index 3abaacc9..e2e78960 100644
--- a/mesh_looptools.py
+++ b/mesh_looptools.py
@@ -28,8 +28,7 @@ bl_info = {
     "location": "View3D > Sidebar > Edit Tab / Edit Mode Context Menu",
     "warning": "",
     "description": "Mesh modelling toolkit. Several tools to aid modelling",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "mesh/looptools.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/mesh/looptools.html",
     "category": "Mesh",
 }
 
diff --git a/mesh_tools/__init__.py b/mesh_tools/__init__.py
index d55ce7e6..f93baea9 100644
--- a/mesh_tools/__init__.py
+++ b/mesh_tools/__init__.py
@@ -29,8 +29,7 @@ bl_info = {
     "location": "View3D > Sidebar > Edit Tab / Edit Mode Context Menu",
     "warning": "",
     "description": "Mesh modelling toolkit. Several tools to aid modelling",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "mesh/edit_mesh_tools.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/mesh/edit_mesh_tools.html",
     "category": "Mesh",
 }
 
diff --git a/node_arrange.py b/node_arrange.py
index 6d3ed807..bab8b333 100644
--- a/node_arrange.py
+++ b/node_arrange.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "Node Editor > Properties > Trees",
     "description": "Node Tree Arrangement Tools",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "node/node_arrange.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/node/node_arrange.html",
     "tracker_url": "https://github.com/JuhaW/NodeArrange/issues",
     "category": "Node"
 }
diff --git a/node_presets.py b/node_presets.py
index 85a262e1..d6a70898 100644
--- a/node_presets.py
+++ b/node_presets.py
@@ -25,8 +25,7 @@ bl_info = {
     "location": "Node Editors > Add > Template",
     "description": "Add node groups directly to the node editors",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "node/node_presets.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/node/node_presets.html",
     "category": "Node",
 }
 
diff --git a/node_wrangler.py b/node_wrangler.py
index eba5b60d..3526d2c7 100644
--- a/node_wrangler.py
+++ b/node_wrangler.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "Node Editor Toolbar or Shift-W",
     "description": "Various tools to enhance and speed up node-based workflow",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "node/node_wrangler.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/node/node_wrangler.html",
     "category": "Node",
 }
 
diff --git a/object_boolean_tools.py b/object_boolean_tools.py
index 7ea231e9..3000f588 100644
--- a/object_boolean_tools.py
+++ b/object_boolean_tools.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "View3D > Sidebar > Edit Tab",
     "description": "Bool Tool Hotkey: Ctrl Shift B",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "object/bool_tools.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/object/bool_tools.html",
     "category": "Object",
 }
 
diff --git a/object_carver/__init__.py b/object_carver/__init__.py
index 883d5b76..dc21fb4d 100644
--- a/object_carver/__init__.py
+++ b/object_carver/__init__.py
@@ -24,8 +24,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "3D View > Ctrl/Shift/x",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "object/carver.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/object/carver.html",
     "support": 'COMMUNITY',
     "category": "Object"
     }
diff --git a/object_collection_manager/__init__.py b/object_collection_manager/__init__.py
index 580a46e0..39a22906 100644
--- a/object_collection_manager/__init__.py
+++ b/object_collection_manager/__init__.py
@@ -22,12 +22,11 @@ bl_info = {
     "name": "Collection Manager",
     "description": "Manage collections and their objects",
     "author": "Ryan Inch",
-    "version": (1,9,2),
+    "version": (1,9,3),
     "blender": (2, 80, 0),
     "location": "View3D - Object Mode (Shortcut - M)",
     "warning": '',  # used for warning icon and text in addons panel
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "interface/collection_manager.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/interface/collection_manager.html",
     "category": "Interface",
 }
 
@@ -45,12 +44,28 @@ else:
     from . import ui
 
 import bpy
+from bpy.types import PropertyGroup
 from bpy.props import (
     CollectionProperty,
     IntProperty,
     BoolProperty,
+    PointerProperty,
     )
 
+
+class CollectionManagerProperties(PropertyGroup):
+    cm_list_collection: CollectionProperty(type=internals.CMListCollection)
+    cm_list_index: IntProperty(update=ui.update_selection)
+
+    show_exclude: BoolProperty(default=True, name="Exclude from View Layer")
+    show_selectable: BoolProperty(default=True, name="Selectable")
+    show_hide_viewport: BoolProperty(default=True, name="Hide in Viewport")
+    show_disable_viewport: BoolProperty(default=False, name="Disable in Viewports")
+    show_render: BoolProperty(default=False, name="Disable in Renders")
+
+    in_phantom_mode: BoolProperty(default=False)
+
+
 addon_keymaps = []
 
 classes = (
@@ -75,23 +90,14 @@ classes = (
     ui.CM_UL_items,
     ui.CollectionManager,
     ui.CMRestrictionTogglesPanel,
+    CollectionManagerProperties,
     )
 
 def register():
     for cls in classes:
         bpy.utils.register_class(cls)
 
-    bpy.types.Scene.CMListCollection = CollectionProperty(type=internals.CMListCollection)
-    bpy.types.Scene.CMListIndex = IntProperty(update=ui.update_selection)
-
-    bpy.types.Scene.show_exclude = BoolProperty(default=True, name="Exclude from View Layer")
-    bpy.types.Scene.show_selectable = BoolProperty(default=True, name="Selectable")
-    bpy.types.Scene.show_hideviewport = BoolProperty(default=True, name="Hide in Viewport")
-    bpy.types.Scene.show_disableviewport = BoolProperty(default=False, name="Disable in Viewports")
-    bpy.types.Scene.show_render = BoolProperty(default=False, name="Disable in Renders")
-
-    bpy.types.Scene.CM_Phantom_Mode = BoolProperty(default=False)
-
+    bpy.types.Scene.collection_manager = PointerProperty(type=CollectionManagerProperties)
 
     # create the global menu hotkey
     wm = bpy.context.window_manager
@@ -103,16 +109,7 @@ def unregister():
     for cls in classes:
         bpy.utils.unregister_class(cls)
 
-    del bpy.types.Scene.CMListCollection
-    del bpy.types.Scene.CMListIndex
-
-    del bpy.types.Scene.show_exclude
-    del bpy.types.Scene.show_selectable
-    del bpy.types.Scene.show_hideviewport
-    del bpy.types.Scene.show_disableviewport
-    del bpy.types.Scene.show_render
-
-    del bpy.types.Scene.CM_Phantom_Mode
+    del bpy.types.Scene.collection_manager
 
     # remove keymaps when add-on is deactivated
     for km, kmi in addon_keymaps:
diff --git a/object_collection_manager/internals.py b/object_collection_manager/internals.py
index 64c48150..5267b1c6 100644
--- a/object_collection_manager/internals.py
+++ b/object_collection_manager/internals.py
@@ -65,10 +65,11 @@ def update_collection_tree(context):
     max_lvl = 0
     row_index = 0
 
-    init_laycol_list = context.view_layer.layer_collection.children
+    layer_collection = context.view_layer.layer_collection
+    init_laycol_list = layer_collection.children
 
     master_laycol = {"id": 0,
-                     "name": context.view_layer.layer_collection.name,
+                     "name": layer_collection.name,
                      "lvl": -1,
                      "row_index": -1,
                      "visible": True,
@@ -76,7 +77,7 @@ def update_collection_tree(context):
                      "expanded": True,
                      "parent": None,
                      "children": [],
-                     "ptr": context.view_layer.layer_collection
+                     "ptr": layer_collection
                      }
 
     get_all_collections(context, init_laycol_list, master_laycol, collection_tree, visible=True)
@@ -120,15 +121,17 @@ def get_all_collections(context, collections, parent, tree, level=0, visible=Fal
 
 def update_property_group(context):
     update_collection_tree(context)
-    context.scene.CMListCollection.clear()
+    context.scene.collection_manager.cm_list_collection.clear()
     create_property_group(context, collection_tree)
 
 
 def create_property_group(context, tree):
     global in_filter
 
+    cm = context.scene.collection_manager
+
     for laycol in tree:
-        new_cm_listitem = context.scene.CMListCollection.add()
+        new_cm_listitem = cm.cm_list_collection.add()
         new_cm_listitem.name = laycol["name"]
 
         if laycol["has_children"]:
diff --git a/object_collection_manager/operators.py b/object_collection_manager/operators.py
index bd23f8a9..7f693ac9 100644
--- a/object_collection_manager/operators.py
+++ b/object_collection_manager/operators.py
@@ -120,7 +120,7 @@ class ExpandSublevelOperator(Operator):
 
 
         # set selected row to the collection you're expanding/collapsing and update tree view
-        context.scene.CMListIndex = self.index
+        context.scene.collection_manager.cm_list_index = self.index
         update_property_group(context)
 
         return {'FINISHED'}
@@ -192,7 +192,8 @@ class CMExcludeOperator(Operator):
         if modifiers == {"shift"}:
             # isolate/de-isolate exclusion of collections
 
-            active_layer_collections = [x["ptr"] for x in layer_collections.values() if not x["ptr"].exclude]
+            active_layer_collections = [x["ptr"] for x in layer_collections.values()
+                                        if not x["ptr"].exclude]
 
             # check if previous state should be restored
             if cls.isolated and self.name == target:
@@ -206,7 +207,8 @@ class CMExcludeOperator(Operator):
                 cls.isolated = False
 
             # check if all collections should be enabled
-            elif len(active_layer_collections) == 1 and active_layer_collections[0].name == self.name:
+            elif (len(active_layer_collections) == 1 and
+                  active_layer_collections[0].name == self.name):
                 # enable all collections
                 for item in layer_collections.values():
                     item["ptr"].exclude = False
@@ -441,8 +443,8 @@ class CMRestrictSelectOperator(Operator):
             laycol = layer_collections[self.name]
 
             # get active collections
-            active_layer_collections = [x["ptr"] for x in layer_collections.values() \
-                                          if x["ptr"].collection.hide_select == False]
+            active_layer_collections = [x["ptr"] for x in layer_collections.values()
+                                        if x["ptr"].collection.hide_select == False]
 
             # check if previous state should be restored
             if cls.isolated and self.name == target:
@@ -456,7 +458,8 @@ class CMRestrictSelectOperator(Operator):
                 cls.isolated = False
 
             # check if all collections should be enabled
-            elif len(active_layer_collections) == 1 and active_layer_collections[0].name == self.name:
+            elif (len(active_layer_collections) == 1 and
+                  active_layer_collections[0].name == self.name):
                 # make all collections selectable
                 for item in layer_collections.values():
                     item["ptr"].collection.hide_select = False
@@ -622,17 +625,19 @@ class CMUnRestrictSelectAllOperator(Operator):
             keep_history = False
 
             for item in layer_collections.values():
+                collection = item["ptr"].collection
+
                 if event.shift:
                     keep_history = True
-                    select_all_history.append(item["ptr"].collection.hide_select)
-                    item["ptr"].collection.hide_select = not item["ptr"].collection.hide_select
+                    select_all_history.append(collection.hide_select)
+                    collection.hide_select = not collection.hide_select
 
                 else:
-                    if item["ptr"].collection.hide_select:
+                    if collection.hide_select:
                         keep_history = True
 
-                    select_all_history.append(item["ptr"].collection.hide_select)
-                    item["ptr"].collection.hide_select = False
+                    select_all_history.append(collection.hide_select)
+                    collection.hide_select = False
 
             if not keep_history:
                 del rto_history["select_all"][view_layer]
@@ -677,8 +682,8 @@ class CMHideOperator(Operator):
             laycol = layer_collections[self.name]
 
             # get active collections
-            active_layer_collections = [x["ptr"] for x in layer_collections.values() \
-                                          if x["ptr"].hide_viewport == False]
+            active_layer_collections = [x["ptr"] for x in layer_collections.values()
+                                        if x["ptr"].hide_viewport == False]
 
             # check if previous state should be restored
             if cls.isolated and self.name == target:
@@ -692,7 +697,8 @@ class CMHideOperator(Operator):
                 cls.isolated = False
 
             # check if all collections should be enabled
-            elif len(active_layer_collections) == 1 and active_layer_collections[0].name == self.name:
+            elif (len(active_layer_collections) == 1 and
+                  active_layer_collections[0].name == self.name):
                 # show all collections
                 for laycol in layer_collections.values():
                     laycol["ptr"].hide_viewport = False
@@ -913,8 +919,8 @@ class CMDisableViewportOperator(Operator):
             laycol = layer_collections[self.name]
 
             # get active collections
-            active_layer_collections = [x["ptr"] for x in layer_collections.values() \
-                                          if x["ptr"].collection.hide_viewport == False]
+            active_layer_collections = [x["ptr"] for x in layer_collections.values()
+                                        if x["ptr"].collection.hide_viewport == False]
 
             # check if previous state should be restored
             if cls.isolated and self.name == target:
@@ -928,7 +934,8 @@ class CMDisableViewportOperator(Operator):
                 cls.isolated = False
 
             # check if all collections should be enabled
-            elif len(active_layer_collections) == 1 and active_layer_collections[0].name == self.name:
+            elif (len(active_layer_collections) == 1 and
+                  active_layer_collections[0].name == self.name):
                 # enable all collections in viewport
                 for laycol in layer_collections.values():
                     laycol["ptr"].collection.hide_viewport = False
@@ -1094,18 +1101,19 @@ class CMUnDisableViewportAllOperator(Operator):
             keep_history = False
 
             for item in layer_collections.values():
+                collection = item["ptr"].collection
+
                 if event.shift:
                     keep_history = True
-                    disable_all_history.append(item["ptr"].collection.hide_viewport)
-                    item["ptr"].collection.hide_viewport = not \
-                        item["ptr"].collection.hide_viewport
+                    disable_all_history.append(collection.hide_viewport)
+                    collection.hide_viewport = not collection.hide_viewport
 
                 else:
-                    if item["ptr"].collection.hide_viewport:
+                    if collection.hide_viewport:
                         keep_history = True
 
-                    disable_all_history.append(item["ptr"].collection.hide_viewport)
-                    item["ptr"].collection.hide_viewport = False
+                    disable_all_history.append(collection.hide_viewport)
+                    collection.hide_viewport = False
 
             if not keep_history:
                 del rto_history["disable_all"][view_layer]
@@ -1150,8 +1158,8 @@ class CMDisableRenderOperator(Operator):
             laycol = layer_collections[self.name]
 
             # get active collections
-            active_layer_collections = [x["ptr"] for x in layer_collections.values() \
-                                          if x["ptr"].collection.hide_render == False]
+            active_layer_collections = [x["ptr"] for x in layer_collections.values()
+                                        if x["ptr"].collection.hide_render == False]
 
             # check if previous state should be restored
             if cls.isolated and self.name == target:
@@ -1165,7 +1173,8 @@ class CMDisableRenderOperator(Operator):
                 cls.isolated = False
 
             # check if all collections should be enabled
-            elif len(active_layer_collections) == 1 and active_layer_collections[0].name == self.name:
+            elif (len(active_layer_collections) == 1 and
+                  active_layer_collections[0].name == self.name):
                 # allow render of all collections
                 for laycol in layer_collections.values():
                     laycol["ptr"].collection.hide_render = False
@@ -1331,18 +1340,19 @@ class CMUnDisableRenderAllOperator(Operator):
             keep_history = False
 
             for item in layer_collections.values():
+                collection = item["ptr"].collection
+
                 if event.shift:
                     keep_history = True
-                    render_all_history.append(item["ptr"].collection.hide_render)
-                    item["ptr"].collection.hide_render = not \
-                        item["ptr"].collection.hide_render
+                    render_all_history.append(collection.hide_render)
+                    collection.hide_render = not collection.hide_render
 
                 else:
-                    if item["ptr"].collection.hide_render:
+                    if collection.hide_render:
                         keep_history = True
 
-                    render_all_history.append(item["ptr"].collection.hide_render)
-                    item["ptr"].collection.hide_render = False
+                    render_all_history.append(collection.hide_render)
+                    collection.hide_render = False
 
             if not keep_history:
                 del rto_history["render_all"][view_layer]
@@ -1367,6 +1377,8 @@ class CMRemoveCollectionOperator(Operator):
     def execute(self, context):
         global rto_history
 
+        cm = context.scene.collection_manager
+
         laycol = layer_collections[self.collection_name]
         collection = laycol["ptr"].collection
         parent_collection = laycol["parent"]["ptr"].collection
@@ -1389,8 +1401,8 @@ class CMRemoveCollectionOperator(Operator):
         update_property_group(context)
 
 
-        if len(context.scene.CMListCollection) == context.scene.CMListIndex:
-            context.scene.CMListIndex = len(context.scene.CMListCollection) - 1
+        if len(cm.cm_list_collection) == cm.cm_list_index:
+            cm.cm_list_index = len(cm.cm_list_collection) - 1
             update_property_group(context)
 
 
@@ -1413,12 +1425,13 @@ class CMNewCollectionOperator(Operator):
         global rto_history
 
         new_collection = bpy.data.collections.new('Collection')
-        scn = context.scene
+        cm = context.scene.collection_manager
+
 
         # if there are collections
-        if len(scn.CMListCollection) > 0:
+        if len(cm.cm_list_collection) > 0:
             # get selected collection
-            laycol = layer_collections[scn.CMListCollection[scn.CMListIndex].name]
+            laycol = layer_collections[cm.cm_list_collection[cm.cm_list_index].name]
 
             # add new collection
             if self.child:
@@ -1428,7 +1441,7 @@ class CMNewCollectionOperator(Operator):
                 # update tree view property
                 update_property_group(context)
 
-                scn.CMListIndex = layer_collections[new_collection.name]["row_index"]
+                cm.cm_list_index = layer_collections[new_collection.name]["row_index"]
 
             else:
                 laycol["parent"]["ptr"].collection.children.link(new_collection)
@@ -1436,16 +1449,16 @@ class CMNewCollectionOperator(Operator):
                 # update tree view property
                 update_property_group(context)
 
-                scn.CMListIndex = layer_collections[new_collection.name]["row_index"]
+                cm.cm_list_index = layer_collections[new_collection.name]["row_index"]
 
         # if no collections add top level collection and select it
         else:
-            scn.collection.children.link(new_collection)
+            context.scene.collection.children.link(new_collection)
 
             # update tree view property
             update_property_group(context)
 
-            scn.CMListIndex = 0
+            cm.cm_list_index = 0
 
         global rename
         rename[0] = True
@@ -1482,18 +1495,18 @@ class CMPhantomModeOperator(Operator):
         global phantom_history
         global rto_history
 
-        scn = context.scene
-        view_layer = context.view_layer.name
+        cm = context.scene.collection_manager
+        view_layer = context.view_layer
 
         # enter Phantom Mode
-        if not scn.CM_Phantom_Mode:
+        if not cm.in_phantom_mode:
 
-            scn.CM_Phantom_Mode = True
+            cm.in_phantom_mode = True
 
             # save current visibility state
-            phantom_history["view_layer"] = view_layer
+            phantom_history["view_layer"] = view_layer.name
 
-            laycol_iter_list = [context.view_layer.layer_collection.children]
+            laycol_iter_list = [view_layer.layer_collection.children]
             while len(laycol_iter_list) > 0:
                 new_laycol_iter_list = []
                 for laycol_iter in laycol_iter_list:
@@ -1514,13 +1527,13 @@ class CMPhantomModeOperator(Operator):
 
             # save current rto history
             for rto, history, in rto_history.items():
-                if history.get(view_layer, None):
-                    phantom_history[rto+"_history"] = deepcopy(history[view_layer])
+                if history.get(view_layer.name, None):
+                    phantom_history[rto+"_history"] = deepcopy(history[view_layer.name])
 
 
         # return to normal mode
         else:
-            laycol_iter_list = [context.view_layer.layer_collection.children]
+            laycol_iter_list = [view_layer.layer_collection.children]
             while len(laycol_iter_list) > 0:
                 new_laycol_iter_list = []
                 for laycol_iter in laycol_iter_list:
@@ -1551,15 +1564,15 @@ class CMPhantomModeOperator(Operator):
 
             # restore previous rto history
             for rto, history, in rto_history.items():
-                if view_layer in history:
-                    del history[view_layer]
+                if view_layer.name in history:
+                    del history[view_layer.name]
 
                 if phantom_history[rto+"_history"]:
-                    history[view_layer] = deepcopy(phantom_history[rto+"_history"])
+                    history[view_layer.name] = deepcopy(phantom_history[rto+"_history"])
 
                 phantom_history[rto+"_history"].clear()
 
-            scn.CM_Phantom_Mode = False
+            cm.in_phantom_mode = False
 
 
         return {'FINISHED'}
diff --git a/object_collection_manager/ui.py b/object_collection_manager/ui.py
index dfdeb889..dcd804fa 100644
--- a/object_collection_manager/ui.py
+++ b/object_collection_manager/ui.py
@@ -49,12 +49,12 @@ class CollectionManager(Operator):
 
     def draw(self, context):
         layout = self.layout
-        scn = context.scene
-        view_layer = context.view_layer.name
+        cm = context.scene.collection_manager
+        view_layer = context.view_layer
 
-        if view_layer != self.last_view_layer:
+        if view_layer.name != self.last_view_layer:
             update_collection_tree(context)
-            self.last_view_layer = view_layer
+            self.last_view_layer = view_layer.name
 
         title_row = layout.split(factor=0.5)
         main = title_row.row()
@@ -63,7 +63,7 @@ class CollectionManager(Operator):
 
         main.label(text="Collection Manager")
 
-        view.prop(context.view_layer, "use", text="")
+        view.prop(view_layer, "use", text="")
         view.separator()
 
         window = context.window
@@ -104,48 +104,54 @@ class CollectionManager(Operator):
         sec2 = toggle_row.row()
         sec2.alignment = 'RIGHT'
 
-        if scn.show_exclude:
-            exclude_all_history = rto_history["exclude_all"].get(view_layer, [])
+        if cm.show_exclude:
+            exclude_all_history = rto_history["exclude_all"].get(view_layer.name, [])
             depress = True if len(exclude_all_history) else False
 
             sec2.operator("view3d.un_exclude_all_collections", text="", icon='CHECKBOX_HLT', depress=depress)
 
-        if scn.show_selectable:
-            select_all_history = rto_history["select_all"].get(view_layer, [])
+        if cm.show_selectable:
+            select_all_history = rto_history["select_all"].get(view_layer.name, [])
             depress = True if len(select_all_history) else False
 
             sec2.operator("view3d.un_restrict_select_all_collections", text="", icon='RESTRICT_SELECT_OFF', depress=depress)
 
-        if scn.show_hideviewport:
-            hide_all_history = rto_history["hide_all"].get(view_layer, [])
+        if cm.show_hide_viewport:
+            hide_all_history = rto_history["hide_all"].get(view_layer.name, [])
             depress = True if len(hide_all_history) else False
 
             sec2.operator("view3d.un_hide_all_collections", text="", icon='HIDE_OFF', depress=depress)
 
-        if scn.show_disableviewport:
-            disable_all_history = rto_history["disable_all"].get(view_layer, [])
+        if cm.show_disable_viewport:
+            disable_all_history = rto_history["disable_all"].get(view_layer.name, [])
             depress = True if len(disable_all_history) else False
 
             sec2.operator("view3d.un_disable_viewport_all_collections", text="", icon='RESTRICT_VIEW_OFF', depress=depress)
 
-        if scn.show_render:
-            render_all_history = rto_history["render_all"].get(view_layer, [])
+        if cm.show_render:
+            render_all_history = rto_history["render_all"].get(view_layer.name, [])
             depress = True if len(render_all_history) else False
 
             sec2.operator("view3d.un_disable_render_all_collections", text="", icon='RESTRICT_RENDER_OFF', depress=depress)
 
-        layout.row().template_list("CM_UL_items", "", context.scene, "CMListCollection", context.scene, "CMListIndex", rows=15, sort_lock=True)
+        layout.row().template_list("CM_UL_items", "",
+                                   cm, "cm_list_collection",
+                                   cm, "cm_list_index",
+                                   rows=15,
+                                   sort_lock=True)
 
         addcollec_row = layout.row()
-        addcollec_row.operator("view3d.add_collection", text="Add Collection", icon='COLLECTION_NEW').child = False
+        addcollec_row.operator("view3d.add_collection", text="Add Collection",
+                               icon='COLLECTION_NEW').child = False
 
-        addcollec_row.operator("view3d.add_collection", text="Add SubCollection", icon='COLLECTION_NEW').child = True
+        addcollec_row.operator("view3d.add_collection", text="Add SubCollection",
+                               icon='COLLECTION_NEW').child = True
 
         phantom_row = layout.row()
-        toggle_text = "Disable " if scn.CM_Phantom_Mode else "Enable "
+        toggle_text = "Disable " if cm.in_phantom_mode else "Enable "
         phantom_row.operator("view3d.toggle_phantom_mode", text=toggle_text+"Phantom Mode")
 
-        if scn.CM_Phantom_Mode:
+        if cm.in_phantom_mode:
             view.enabled = False
             addcollec_row.enabled = False
 
@@ -154,23 +160,27 @@ class CollectionManager(Operator):
         wm = context.window_manager
 
         update_property_group(context)
-        self.view_layer = context.view_layer.name
+
+        cm = context.scene.collection_manager
+        view_layer = context.view_layer
+
+        self.view_layer = view_layer.name
 
         # sync selection in ui list with active layer collection
         try:
-            active_laycol_name = context.view_layer.active_layer_collection.name
+            active_laycol_name = view_layer.active_layer_collection.name
             active_laycol_row_index = layer_collections[active_laycol_name]["row_index"]
-            context.scene.CMListIndex = active_laycol_row_index
+            cm.cm_list_index = active_laycol_row_index
         except:
-            context.scene.CMListIndex = -1
+            cm.cm_list_index = -1
 
         # check if in phantom mode and if it's still viable
-        if context.scene.CM_Phantom_Mode:
+        if cm.in_phantom_mode:
             if set(layer_collections.keys()) != set(phantom_history["initial_state"].keys()):
-                context.scene.CM_Phantom_Mode = False
+                cm.in_phantom_mode = False
 
-            if context.view_layer.name != phantom_history["view_layer"]:
-                context.scene.CM_Phantom_Mode = False
+            if view_layer.name != phantom_history["view_layer"]:
+                cm.in_phantom_mode = False
 
         # handle window sizing
         max_width = 960
@@ -191,12 +201,12 @@ class CollectionManager(Operator):
 
 
 def update_selection(self, context):
-    scn = context.scene
+    cm = context.scene.collection_manager
 
-    if scn.CMListIndex == -1:
+    if cm.cm_list_index == -1:
         return
 
-    selected_item = scn.CMListCollection[scn.CMListIndex]
+    selected_item = cm.cm_list_collection[cm.cm_list_index]
     layer_collection = layer_collections[selected_item.name]["ptr"]
 
     context.view_layer.active_layer_collection = layer_collection
@@ -250,8 +260,8 @@ class CM_UL_items(UIList):
     def draw_item(self, context, layout, data, item, icon, active_data,active_propname, index):
         self.use_filter_show = True
 
-        scn = context.scene
-        view_layer = context.view_layer.name
+        cm = context.scene.collection_manager
+        view_layer = context.view_layer
         laycol = layer_collections[item.name]
         collection = laycol["ptr"].collection
 
@@ -267,13 +277,15 @@ class CM_UL_items(UIList):
         # add expander if collection has children to make UIList act like tree view
         if laycol["has_children"]:
             if laycol["expanded"]:
-                prop = row.operator("view3d.expand_sublevel", text="", icon='DISCLOSURE_TRI_DOWN', emboss=False)
+                prop = row.operator("view3d.expand_sublevel", text="",
+                                    icon='DISCLOSURE_TRI_DOWN', emboss=False)
                 prop.expand = False
                 prop.name = item.name
                 prop.index = index
 
             else:
-                prop = row.operator("view3d.expand_sublevel", text="", icon='DISCLOSURE_TRI_RIGHT', emboss=False)
+                prop = row.operator("view3d.expand_sublevel", text="",
+                                    icon='DISCLOSURE_TRI_RIGHT', emboss=False)
                 prop.expand = True
                 prop.name = item.name
                 prop.index = index
@@ -286,7 +298,7 @@ class CM_UL_items(UIList):
 
         name_row = row.row()
 
-        #if rename[0] and index == scn.CMListIndex:
+        #if rename[0] and index == cm.cm_list_index:
             #name_row.activate_init = True
             #rename[0] = False
 
@@ -308,72 +320,77 @@ class CM_UL_items(UIList):
             row_setcol.enabled = False
 
 
-        prop = row_setcol.operator("view3d.set_collection", text="", icon=icon, emboss=False)
+        prop = row_setcol.operator("view3d.set_collection", text="",
+                                   icon=icon, emboss=False)
         prop.collection_index = laycol["id"]
         prop.collection_name = item.name
 
 
-        if scn.show_exclude:
-            exclude_history_base = rto_history["exclude"].get(view_layer, {})
+        if cm.show_exclude:
+            exclude_history_base = rto_history["exclude"].get(view_layer.name, {})
             exclude_target = exclude_history_base.get("target", "")
             exclude_history = exclude_history_base.get("history", [])
 
-            depress = True if len(exclude_history) and exclude_target == item.name else False
-            emboss = True if len(exclude_history) and exclude_target == item.name else False
+            highlight = bool(exclude_history and exclude_target == item.name)
             icon = 'CHECKBOX_DEHLT' if laycol["ptr"].exclude else 'CHECKBOX_HLT'
 
-            row.operator("view3d.exclude_collection", text="", icon=icon, emboss=emboss, depress=depress).name = item.name
+            row.operator("view3d.exclude_collection", text="", icon=icon,
+                         emboss=highlight, depress=highlight).name = item.name
 
-        if scn.show_selectable:
-            select_history_base = rto_history["select"].get(view_layer, {})
+        if cm.show_selectable:
+            select_history_base = rto_history["select"].get(view_layer.name, {})
             select_target = select_history_base.get("target", "")
             select_history = select_history_base.get("history", [])
 
-            depress = True if len(select_history) and select_target == item.name else False
-            emboss = True if len(select_history) and select_target == item.name else False
-            icon = 'RESTRICT_SELECT_ON' if laycol["ptr"].collection.hide_select else 'RESTRICT_SELECT_OFF'
+            highlight = bool(select_history and select_target == item.name)
+            icon = ('RESTRICT_SELECT_ON' if laycol["ptr"].collection.hide_select else
+                    'RESTRICT_SELECT_OFF')
 
-            row.operator("view3d.restrict_select_collection", text="", icon=icon, emboss=emboss, depress=depress).name = item.name
+            row.operator("view3d.restrict_select_collection", text="", icon=icon,
+                         emboss=highlight, depress=highlight).name = item.name
 
-        if scn.show_hideviewport:
-            hide_history_base = rto_history["hide"].get(view_layer, {})
+        if cm.show_hide_viewport:
+            hide_history_base = rto_history["hide"].get(view_layer.name, {})
             hide_target = hide_history_base.get("target", "")
             hide_history = hide_history_base.get("history", [])
 
-            depress = True if len(hide_history) and hide_target == item.name else False
-            emboss = True if len(hide_history) and hide_target == item.name else False
+            highlight = bool(hide_history and hide_target == item.name)
             icon = 'HIDE_ON' if laycol["ptr"].hide_viewport else 'HIDE_OFF'
 
-            row.operator("view3d.hide_collection", text="", icon=icon, emboss=emboss, depress=depress).name = item.name
+            row.operator("view3d.hide_collection", text="", icon=icon,
+                         emboss=highlight, depress=highlight).name = item.name
 
-        if scn.show_disableviewport:
-            disable_history_base = rto_history["disable"].get(view_layer, {})
+        if cm.show_disable_viewport:
+            disable_history_base = rto_history["disable"].get(view_layer.name, {})
             disable_target = disable_history_base.get("target", "")
             disable_history = disable_history_base.get("history", [])
 
-            depress = True if len(disable_history) and disable_target == item.name else False
-            emboss = True if len(disable_history) and disable_target == item.name else False
-            icon = 'RESTRICT_VIEW_ON' if laycol["ptr"].collection.hide_viewport else 'RESTRICT_VIEW_OFF'
+            highlight = bool(disable_history and disable_target == item.name)
+            icon = ('RESTRICT_VIEW_ON' if laycol["ptr"].collection.hide_viewport else
+                    'RESTRICT_VIEW_OFF')
 
-            row.operator("view3d.disable_viewport_collection", text="", icon=icon, emboss=emboss, depress=depress).name = item.name
+            row.operator("view3d.disable_viewport_collection", text="", icon=icon,
+                         emboss=highlight, depress=highlight).name = item.name
 
-        if scn.show_render:
-            render_history_base = rto_history["render"].get(view_layer, {})
+        if cm.show_render:
+            render_history_base = rto_history["render"].get(view_layer.name, {})
             render_target = render_history_base.get("target", "")
             render_history = render_history_base.get("history", [])
 
-            depress = True if len(render_history) and render_target == item.name else False
-            emboss = True if len(render_history) and render_target == item.name else False
-            icon = 'RESTRICT_RENDER_ON' if laycol["ptr"].collection.hide_render else 'RESTRICT_RENDER_OFF'
+            highlight = bool(render_history and render_target == item.name)
+            icon = ('RESTRICT_RENDER_ON' if laycol["ptr"].collection.hide_render else
+                    'RESTRICT_RENDER_OFF')
 
-            row.operator("view3d.disable_render_collection", text="", icon=icon, emboss=emboss, depress=depress).name = item.name
+            row.operator("view3d.disable_render_collection", text="", icon=icon,
+                         emboss=highlight, depress=highlight).name = item.name
 
 
         rm_op = split.row()
         rm_op.alignment = 'RIGHT'
-        rm_op.operator("view3d.remove_collection", text="", icon='X', emboss=False).collection_name = item.name
+        rm_op.operator("view3d.remove_collection", text="", icon='X',
+                       emboss=False).collection_name = item.name
 
-        if scn.CM_Phantom_Mode:
+        if cm.in_phantom_mode:
             name_row.enabled = False
             row_setcol.enabled = False
             rm_op.enabled = False
@@ -432,13 +449,13 @@ class CMRestrictionTogglesPanel(Panel):
     bl_region_type = 'HEADER'
 
     def draw(self, context):
+        cm = context.scene.collection_manager
 
         layout = self.layout
-
         row = layout.row()
 
-        row.prop(context.scene, "show_exclude", icon='CHECKBOX_HLT', icon_only=True)
-        row.prop(context.scene, "show_selectable", icon='RESTRICT_SELECT_OFF', icon_only=True)
-        row.prop(context.scene, "show_hideviewport", icon='HIDE_OFF', icon_only=True)
-        row.prop(context.scene, "show_disableviewport", icon='RESTRICT_VIEW_OFF', icon_only=True)
-        row.prop(context.scene, "show_render", icon='RESTRICT_RENDER_OFF', icon_only=True)
+        row.prop(cm, "show_exclude", icon='CHECKBOX_HLT', icon_only=True)
+        row.prop(cm, "show_selectable", icon='RESTRICT_SELECT_OFF', icon_only=True)
+        row.prop(cm, "show_hide_viewport", icon='HIDE_OFF', icon_only=True)
+        row.prop(cm, "show_disable_viewport", icon='RESTRICT_VIEW_OFF', icon_only=True)
+        row.prop(cm, "show_render", icon='RESTRICT_RENDER_OFF', icon_only=True)
diff --git a/object_color_rules.py b/object_color_rules.py
index ff1b1ab2..1d60e295 100644
--- a/object_color_rules.py
+++ b/object_color_rules.py
@@ -23,8 +23,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "Properties > Object Buttons",
     "description": "Rules for assigning object color (for object & wireframe colors).",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "object/color_rules.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/object/color_rules.html",
     "category": "Object",
 }
 
diff --git a/object_edit_linked.py b/object_edit_linked.py
index 88ea91cb..b6445981 100644
--- a/object_edit_linked.py
+++ b/object_edit_linked.py
@@ -24,8 +24,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "File > External Data / View3D > Sidebar > Item Tab",
     "description": "Allows editing of objects linked from a .blend library.",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "object/edit_linked_library.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/object/edit_linked_library.html",
     "category": "Object",
 }
 
diff --git a/object_fracture_cell/__init__.py b/object_fracture_cell/__init__.py
index 04b47706..2e6d3b08 100644
--- a/object_fracture_cell/__init__.py
+++ b/object_fracture_cell/__init__.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "Viewport Object Menu -> Quick Effects",
     "description": "Fractured Object Creation",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "object/cell_fracture.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/object/cell_fracture.html",
     "category": "Object",
 }
 
diff --git a/object_print3d_utils/__init__.py b/object_print3d_utils/__init__.py
index 04b03a7e..9a2aefbe 100644
--- a/object_print3d_utils/__init__.py
+++ b/object_print3d_utils/__init__.py
@@ -24,7 +24,7 @@ bl_info = {
     "blender": (2, 82, 0),
     "location": "3D View > Sidebar",
     "description": "Utilities for 3D printing",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/mesh/3d_print_toolbox.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/mesh/3d_print_toolbox.html",
     "support": 'OFFICIAL',
     "category": "Mesh",
 }
diff --git a/object_skinify.py b/object_skinify.py
index 58263c9f..177f8de9 100644
--- a/object_skinify.py
+++ b/object_skinify.py
@@ -24,8 +24,7 @@ bl_info = {
     "location": "Pose Mode > Sidebar > Create Tab",
     "description": "Creates a mesh object from selected bones",
     "warning": "Work in progress",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "object/skinify.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/object/skinify.html",
     "category": "Object",
 }
 
diff --git a/paint_palette.py b/paint_palette.py
index 54b6eb17..10b8fe31 100644
--- a/paint_palette.py
+++ b/paint_palette.py
@@ -27,8 +27,7 @@ bl_info = {
     "location": "Image Editor and 3D View > Any Paint mode > Color Palette or Weight Palette panel",
     "description": "Palettes for color and weight paint modes",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "paint/paint_palettes.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/paint/paint_palettes.html",
     "category": "Paint",
 }
 
diff --git a/real_snow.py b/real_snow.py
new file mode 100644
index 00000000..f1091b2d
--- /dev/null
+++ b/real_snow.py
@@ -0,0 +1,415 @@
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+bl_info = {
+    "name": "Real Snow",
+    "description": "Generate snow mesh",
+    "author": "Wolf <wolf.art3d@gmail.com>",
+    "version": (1, 1),
+    "blender": (2, 83, 0),
+    "location": "View 3D > Properties Panel",
+    "doc_url": "https://github.com/macio97/Real-Snow",
+    "tracker_url": "https://github.com/macio97/Real-Snow/issues",
+    "support": "COMMUNITY",
+    "category": "Object",
+    }
+
+
+# Libraries
+import math
+import os
+import random
+import time
+
+import bpy
+import bmesh
+from bpy.props import BoolProperty, FloatProperty, IntProperty, PointerProperty
+from bpy.types import Operator, Panel, PropertyGroup
+from mathutils import Vector
+
+
+# Panel
+class REAL_PT_snow(Panel):
+    bl_space_type = "VIEW_3D"
+    bl_context = "objectmode"
+    bl_region_type = "UI"
+    bl_label = "Snow"
+    bl_category = "Real Snow"
+
+    def draw(self, context):
+        scn = context.scene
+        settings = scn.snow
+        layout = self.layout
+
+        col = layout.column(align=True)
+        col.prop(settings, 'coverage', slider=True)
+        col.prop(settings, 'height')
+
+        layout.use_property_split = True
+        layout.use_property_decorate = False
+        flow = layout.grid_flow(row_major=True, columns=0, even_columns=False, even_rows=False, align=True)
+        col = flow.column()
+        col.prop(settings, 'vertices')
+
+        row = layout.row(align=True)
+        row.scale_y = 1.5
+        row.operator("snow.create", text="Add Snow", icon="FREEZE")
+
+
+class SNOW_OT_Create(Operator):
+    bl_idname = "snow.create"
+    bl_label = "Create Snow"
+    bl_description = "Create snow"
+    bl_options = {'REGISTER', 'UNDO'}
+
+    @classmethod
+    def poll(cls, context) -> bool:
+        return bool(context.selected_objects)
+
+    def execute(self, context):
+        coverage = context.scene.snow.coverage
+        height = context.scene.snow.height
+        vertices = context.scene.snow.vertices
+
+        # get list of selected objects except non-mesh objects
+        input_objects = [obj for obj in context.selected_objects if obj.type == 'MESH']
+        snow_list = []
+        # start UI progress bar
+        length = len(input_objects)
+        context.window_manager.progress_begin(0, 10)
+        timer=0
+        for obj in input_objects:
+            # timer
+            context.window_manager.progress_update(timer)
+            # duplicate mesh
+            bpy.ops.object.select_all(action='DESELECT')
+            obj.select_set(True)
+            context.view_layer.objects.active = obj
+            object_eval = obj.evaluated_get(context.view_layer.depsgraph)
+            mesh_eval = bpy.data.meshes.new_from_object(object_eval)
+            snow_object = bpy.data.objects.new("Snow", mesh_eval)
+            snow_object.matrix_world = obj.matrix_world
+            context.collection.objects.link(snow_object)
+            bpy.ops.object.select_all(action='DESELECT')
+            context.view_layer.objects.active = snow_object
+            snow_object.select_set(True)
+            bpy.ops.object.mode_set(mode = 'EDIT')
+            bm_orig = bmesh.from_edit_mesh(snow_object.data)
+            bm_copy = bm_orig.copy()
+            bm_copy.transform(obj.matrix_world)
+            bm_copy.normal_update()
+            # get faces data
+            delete_faces(vertices, bm_copy, snow_object)
+            ballobj = add_metaballs(context, height, snow_object)
+            context.view_layer.objects.active = snow_object
+            surface_area = area(snow_object)
+            snow = add_particles(context, surface_area, height, coverage, snow_object, ballobj)
+            add_modifiers(snow)
+            # place inside collection
+            context.view_layer.active_layer_collection = context.view_layer.layer_collection
+            if "Snow" not in context.scene.collection.children:
+                coll = bpy.data.collections.new("Snow")
+                context.scene.collection.children.link(coll)
+            else:
+                coll = bpy.data.collections["Snow"]
+            coll.objects.link(snow)
+            context.view_layer.layer_collection.collection.objects.unlink(snow)
+            add_material(snow)
+            # parent with object
+            snow.parent = obj
+            snow.matrix_parent_inverse = obj.matrix_world.inverted()
+            # add snow to list
+            snow_list.append(snow)
+            # update progress bar
+            timer += 0.1 / length
+        # select created snow meshes
+        for s in snow_list:
+            s.select_set(True)
+        # end progress bar
+        context.window_manager.progress_end()
+
+        return {'FINISHED'}
+
+
+def add_modifiers(snow):
+    bpy.ops.object.transform_apply(location=False, scale=True, rotation=False)
+    # decimate the mesh to get rid of some visual artifacts
+    snow.modifiers.new("Decimate", 'DECIMATE')
+    snow.modifiers["Decimate"].ratio = 0.5
+    snow.modifiers.new("Subdiv", "SUBSURF")
+    snow.modifiers["Subdiv"].render_levels = 1
+    snow.modifiers["Subdiv"].quality = 1
+    snow.cycles.use_adaptive_subdivision = True
+
+
+def add_particles(context, surface_area: float, height: float, coverage: float, snow_object: bpy.types.Object, ballobj: bpy.types.Object):
+    # approximate the number of particles to be emitted
+    number = int(surface_area*50*(height**-2)*((coverage/100)**2))
+    bpy.ops.object.particle_system_add()
+    particles = snow_object.particle_systems[0]
+    psettings = particles.settings
+    psettings.type = 'HAIR'
+    psettings.render_type = 'OBJECT'
+    # generate random number for seed
+    random_seed = random.randint(0, 1000)
+    particles.seed = random_seed
+    # set particles object
+    psettings.particle_size = height
+    psettings.instance_object = ballobj
+    psettings.count = number
+    # convert particles to mesh
+    bpy.ops.object.select_all(action='DESELECT')
+    context.view_layer.objects.active = ballobj
+    ballobj.select_set(True)
+    bpy.ops.object.convert(target='MESH')
+    snow = bpy.context.active_object
+    snow.scale = [0.09, 0.09, 0.09]
+    bpy.ops.object.origin_set(type='ORIGIN_GEOMETRY')
+    bpy.ops.object.select_all(action='DESELECT')
+    snow_object.select_set(True)
+    bpy.ops.object.delete()
+    snow.select_set(True)
+    return snow
+
+
+def add_metaballs(context, height: float, snow_object: bpy.types.Object) -> bpy.types.Object:
+    ball_name = "SnowBall"
+    ball = bpy.data.metaballs.new(ball_name)
+    ballobj = bpy.data.objects.new(ball_name, ball)
+    bpy.context.scene.collection.objects.link(ballobj)
+    # these settings have proven to work on a large amount of scenarios
+    ball.resolution = 0.7*height+0.3
+    ball.threshold = 1.3
+    element = ball.elements.new()
+    element.radius = 1.5
+    element.stiffness = 0.75
+    ballobj.scale = [0.09, 0.09, 0.09]
+    return ballobj
+
+
+def delete_faces(vertices, bm_copy, snow_object: bpy.types.Object):
+    # find upper faces
+    if vertices:
+        selected_faces = [face.index for face in bm_copy.faces if face.select]
+    # based on a certain angle, find all faces not pointing up
+    down_faces = [face.index for face in bm_copy.faces if Vector((0, 0, -1.0)).angle(face.normal, 4.0) < (math.pi/2.0+0.5)]
+    bm_copy.free()
+    bpy.ops.mesh.select_all(action='DESELECT')
+    # select upper faces
+    mesh = bmesh.from_edit_mesh(snow_object.data)
+    for face in mesh.faces:
+        if vertices:
+            if not face.index in selected_faces:
+                face.select = True
+        if face.index in down_faces:
+            face.select = True
+    # delete unneccessary faces
+    faces_select = [face for face in mesh.faces if face.select]
+    bmesh.ops.delete(mesh, geom=faces_select, context='FACES_KEEP_BOUNDARY')
+    mesh.free()
+    bpy.ops.object.mode_set(mode = 'OBJECT')
+
+
+def area(obj: bpy.types.Object) -> float:
+    bm_obj = bmesh.new()
+    bm_obj.from_mesh(obj.data)
+    bm_obj.transform(obj.matrix_world)
+    area = sum(face.calc_area() for face in bm_obj.faces)
+    bm_obj.free
+    return area
+
+
+def add_material(obj: bpy.types.Object):
+    mat_name = "Snow"
+    # if material doesn't exist, create it
+    if mat_name in bpy.data.materials:
+	    bpy.data.materials[mat_name].name = mat_name+".001"
+    mat = bpy.data.materials.new(mat_name)
+    mat.use_nodes = True
+    nodes = mat.node_tree.nodes
+    # delete all nodes
+    for node in nodes:
+	    nodes.remove(node)
+    # add nodes
+    output = nodes.new('ShaderNodeOutputMaterial')
+    principled = nodes.new('ShaderNodeBsdfPrincipled')
+    vec_math = nodes.new('ShaderNodeVectorMath')
+    com_xyz = nodes.new('ShaderNodeCombineXYZ')
+    dis = nodes.new('ShaderNodeDisplacement')
+    mul1 = nodes.new('ShaderNodeMath')
+    add1 = nodes.new('ShaderNodeMath')
+    add2 = nodes.new('ShaderNodeMath')
+    mul2 = nodes.new('ShaderNodeMath')
+    mul3 = nodes.new('ShaderNodeMath')
+    ramp1 = nodes.new('ShaderNodeValToRGB')
+    ramp2 = nodes.new('ShaderNodeValToRGB')
+    ramp3 = nodes.new('ShaderNodeValToRGB')
+    vor = nodes.new('ShaderNodeTexVoronoi')
+    noise1 = nodes.new('ShaderNodeTexNoise')
+    noise2 = nodes.new('ShaderNodeTexNoise')
+    noise3 = nodes.new('ShaderNodeTexNoise')
+    mapping = nodes.new('ShaderNodeMapping')
+    coord = nodes.new('ShaderNodeTexCoord')
+    # change location
+    output.location = (100, 0)
+    principled.location = (-200, 500)
+    vec_math.location = (-400, 400)
+    com_xyz.location = (-600, 400)
+    dis.location = (-200, -100)
+    mul1.location = (-400, -100)
+    add1.location = (-600, -100)
+    add2.location = (-800, -100)
+    mul2.location = (-1000, -100)
+    mul3.location = (-1000, -300)
+    ramp1.location = (-500, 150)
+    ramp2.location = (-1300, -300)
+    ramp3.location = (-1000, -500)
+    vor.location = (-1500, 200)
+    noise1.location = (-1500, 0)
+    noise2.location = (-1500, -200)
+    noise3.location = (-1500, -400)
+    mapping.location = (-1700, 0)
+    coord.location = (-1900, 0)
+    # change node parameters
+    principled.distribution = "MULTI_GGX"
+    principled.subsurface_method = "RANDOM_WALK"
+    principled.inputs[0].default_value[0] = 0.904
+    principled.inputs[0].default_value[1] = 0.904
+    principled.inputs[0].default_value[2] = 0.904
+    principled.inputs[1].default_value = 1
+    principled.inputs[2].default_value[0] = 0.36
+    principled.inputs[2].default_value[1] = 0.46
+    principled.inputs[2].default_value[2] = 0.6
+    principled.inputs[3].default_value[0] = 0.904
+    principled.inputs[3].default_value[1] = 0.904
+    principled.inputs[3].default_value[2] = 0.904
+    principled.inputs[5].default_value = 0.224
+    principled.inputs[7].default_value = 0.1
+    principled.inputs[13].default_value = 0.1
+    vec_math.operation = "MULTIPLY"
+    vec_math.inputs[1].default_value[0] = 0.5
+    vec_math.inputs[1].default_value[1] = 0.5
+    vec_math.inputs[1].default_value[2] = 0.5
+    com_xyz.inputs[0].default_value = 0.36
+    com_xyz.inputs[1].default_value = 0.46
+    com_xyz.inputs[2].default_value = 0.6
+    dis.inputs[1].default_value = 0.1
+    dis.inputs[2].default_value = 0.3
+    mul1.operation = "MULTIPLY"
+    mul1.inputs[1].default_value = 0.1
+    mul2.operation = "MULTIPLY"
+    mul2.inputs[1].default_value = 0.6
+    mul3.operation = "MULTIPLY"
+    mul3.inputs[1].default_value = 0.4
+    ramp1.color_ramp.elements[0].position = 0.525
+    ramp1.color_ramp.elements[1].position = 0.58
+    ramp2.color_ramp.elements[0].position = 0.069
+    ramp2.color_ramp.elements[1].position = 0.757
+    ramp3.color_ramp.elements[0].position = 0.069
+    ramp3.color_ramp.elements[1].position = 0.757
+    vor.feature = "N_SPHERE_RADIUS"
+    vor.inputs[2].default_value = 30
+    noise1.inputs[2].default_value = 12
+    noise2.inputs[2].default_value = 2
+    noise2.inputs[3].default_value = 4
+    noise3.inputs[2].default_value = 1
+    noise3.inputs[3].default_value = 4
+    mapping.inputs[3].default_value[0] = 12
+    mapping.inputs[3].default_value[1] = 12
+    mapping.inputs[3].default_value[2] = 12
+    # link nodes
+    link = mat.node_tree.links
+    link.new(principled.outputs[0], output.inputs[0])
+    link.new(vec_math.outputs[0], principled.inputs[2])
+    link.new(com_xyz.outputs[0], vec_math.inputs[0])
+    link.new(dis.outputs[0], output.inputs[2])
+    link.new(mul1.outputs[0], dis.inputs[0])
+    link.new(add1.outputs[0], mul1.inputs[0])
+    link.new(add2.outputs[0], add1.inputs[0])
+    link.new(mul2.outputs[0], add2.inputs[0])
+    link.new(mul3.outputs[0], add2.inputs[1])
+    link.new(ramp1.outputs[0], principled.inputs[12])
+    link.new(ramp2.outputs[0], mul3.inputs[0])
+    link.new(ramp3.outputs[0], add1.inputs[1])
+    link.new(vor.outputs[4], ramp1.inputs[0])
+    link.new(noise1.outputs[0], mul2.inputs[0])
+    link.new(noise2.outputs[0], ramp2.inputs[0])
+    link.new(noise3.outputs[0], ramp3.inputs[0])
+    link.new(mapping.outputs[0], vor.inputs[0])
+    link.new(mapping.outputs[0], noise1.inputs[0])
+    link.new(mapping.outputs[0], noise2.inputs[0])
+    link.new(mapping.outputs[0], noise3.inputs[0])
+    link.new(coord.outputs[3], mapping.inputs[0])
+    # set displacement and add material
+    mat.cycles.displacement_method = "DISPLACEMENT"
+    obj.data.materials.append(mat)
+
+
+# Properties
+class SnowSettings(PropertyGroup):
+    coverage : IntProperty(
+        name = "Coverage",
+        description = "Percentage of the object to be covered with snow",
+        default = 100,
+        min = 0,
+        max = 100,
+        subtype = 'PERCENTAGE'
+        )
+
+    height : FloatProperty(
+        name = "Height",
+        description = "Height of the snow",
+        default = 0.3,
+        step = 1,
+        precision = 2,
+        min = 0.1,
+        max = 1
+        )
+
+    vertices : BoolProperty(
+        name = "Selected Faces",
+        description = "Add snow only on selected faces",
+        default = False
+        )
+
+
+#############################################################################################
+classes = (
+    REAL_PT_snow,
+    SNOW_OT_Create,
+    SnowSettings
+    )
+
+register, unregister = bpy.utils.register_classes_factory(classes)
+
+# Register
+def register():
+    for cls in classes:
+        bpy.utils.register_class(cls)
+    bpy.types.Scene.snow = PointerProperty(type=SnowSettings)
+
+
+# Unregister
+def unregister():
+    for cls in classes:
+        bpy.utils.unregister_class(cls)
+    del bpy.types.Scene.snow
+
+
+if __name__ == "__main__":
+    register()
diff --git a/render_auto_tile_size.py b/render_auto_tile_size.py
index b1cac20b..078513c6 100644
--- a/render_auto_tile_size.py
+++ b/render_auto_tile_size.py
@@ -24,8 +24,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "Render Settings > Performance",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "render/auto_tile_size.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/render/auto_tile_size.html",
     "category": "Render",
 }
 
diff --git a/render_copy_settings/__init__.py b/render_copy_settings/__init__.py
index 32a5fb0c..ecc3603d 100644
--- a/render_copy_settings/__init__.py
+++ b/render_copy_settings/__init__.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "Render buttons (Properties window)",
     "description": "Allows to copy a selection of render settings "
                    "from current scene to others.",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "render/copy_settings.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/render/copy_settings.html",
     "category": "Render",
 }
 
diff --git a/render_freestyle_svg.py b/render_freestyle_svg.py
index a6936bff..cb27ae64 100644
--- a/render_freestyle_svg.py
+++ b/render_freestyle_svg.py
@@ -26,7 +26,7 @@ bl_info = {
     "location": "Properties > Render > Freestyle SVG Export",
     "description": "Exports Freestyle's stylized edges in SVG format",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/render/render_freestyle_svg.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/render/render_freestyle_svg.html",
     "support": 'OFFICIAL',
     "category": "Render",
 }
diff --git a/render_povray/__init__.py b/render_povray/__init__.py
index 8d6b7540..5080aab9 100644
--- a/render_povray/__init__.py
+++ b/render_povray/__init__.py
@@ -102,7 +102,7 @@ bl_info = {
     "blender": (2, 81, 0),
     "location": "Render Properties > Render Engine > Persistence of Vision",
     "description": "Persistence of Vision integration for blender",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/render/povray.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/render/povray.html",
     "category": "Render",
 }
 
diff --git a/rigify/__init__.py b/rigify/__init__.py
index a6e7fa87..00777a78 100644
--- a/rigify/__init__.py
+++ b/rigify/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 81, 0),
     "description": "Automatic rigging from building-block components",
     "location": "Armature properties, Bone properties, View3d tools panel, Armature Add menu",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "rigging/rigify/index.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/rigging/rigify/index.html",
     "category": "Rigging",
 }
 
diff --git a/rigify/rigs/experimental/super_chain.py b/rigify/rigs/experimental/super_chain.py
index 346c16b8..a5af8323 100644
--- a/rigify/rigs/experimental/super_chain.py
+++ b/rigify/rigs/experimental/super_chain.py
@@ -558,7 +558,7 @@ class Rig:
         )
 
         invert_last = True
-        if self.params.wgt_align_axis not in {'y' or '-y'}:
+        if self.params.wgt_align_axis not in {'y', '-y'}:
             invert_last = False
 
         create_chain_widget(
diff --git a/space_clip_editor_refine_solution.py b/space_clip_editor_refine_solution.py
index 13985c2a..457af286 100644
--- a/space_clip_editor_refine_solution.py
+++ b/space_clip_editor_refine_solution.py
@@ -30,8 +30,7 @@ bl_info = {
     "description": "Refine motion solution by setting track weight according"
                    " to reprojection error",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "video_tools/refine_tracking.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/video_tools/refine_tracking.html",
     "category": "Video Tools",
 }
 
diff --git a/space_view3d_3d_navigation.py b/space_view3d_3d_navigation.py
index c8b27323..fea417fe 100644
--- a/space_view3d_3d_navigation.py
+++ b/space_view3d_3d_navigation.py
@@ -30,8 +30,7 @@ bl_info = {
     "location": "View3D > Sidebar > View Tab",
     "description": "Navigate the Camera & 3D View from the Toolshelf",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "3d_view/3d_navigation.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/3d_view/3d_navigation.html",
     "category": "3D View",
 }
 
diff --git a/space_view3d_align_tools.py b/space_view3d_align_tools.py
index c021ff06..8bfa1f6b 100644
--- a/space_view3d_align_tools.py
+++ b/space_view3d_align_tools.py
@@ -26,8 +26,7 @@ bl_info = {
     "location": "View3D > Sidebar > Item Tab",
     "description": "Align Selected Objects to Active Object",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "object/align_tools.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/object/align_tools.html",
     "category": "Object",
 }
 
diff --git a/space_view3d_brush_menus/__init__.py b/space_view3d_brush_menus/__init__.py
index 3607630a..c040bd9d 100644
--- a/space_view3d_brush_menus/__init__.py
+++ b/space_view3d_brush_menus/__init__.py
@@ -27,7 +27,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "Spacebar in Sculpt/Paint Modes",
     "warning": '',
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/interface/brush_menus.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/interface/brush_menus.html",
     "category": "Interface",
 }
 
diff --git a/space_view3d_copy_attributes.py b/space_view3d_copy_attributes.py
index c4bf4c42..4c426551 100644
--- a/space_view3d_copy_attributes.py
+++ b/space_view3d_copy_attributes.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "View3D > Ctrl-C",
     "description": "Copy Attributes Menu from Blender 2.4",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "interface/copy_attributes.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/interface/copy_attributes.html",
     "category": "Interface",
 }
 
diff --git a/space_view3d_math_vis/__init__.py b/space_view3d_math_vis/__init__.py
index 23995374..c56e5f7f 100644
--- a/space_view3d_math_vis/__init__.py
+++ b/space_view3d_math_vis/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "Properties: Scene > Math Vis Console and Python Console: Menu",
     "description": "Display console defined mathutils variables in the 3D view",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "3d_view/math_vis_console.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/3d_view/math_vis_console.html",
     "support": "OFFICIAL",
     "category": "3D View",
 }
diff --git a/space_view3d_modifier_tools.py b/space_view3d_modifier_tools.py
index a4bc1d0e..aaef9b6a 100644
--- a/space_view3d_modifier_tools.py
+++ b/space_view3d_modifier_tools.py
@@ -25,8 +25,7 @@ bl_info = {
     "location": "Properties > Modifiers",
     "description": "Modifiers Specials Show/Hide/Apply Selected",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "interface/modifier_tools.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/interface/modifier_tools.html",
     "category": "Interface"
     }
 
diff --git a/space_view3d_pie_menus/__init__.py b/space_view3d_pie_menus/__init__.py
index a9044df5..783f061a 100644
--- a/space_view3d_pie_menus/__init__.py
+++ b/space_view3d_pie_menus/__init__.py
@@ -39,8 +39,7 @@ bl_info = {
     "description": "Pie Menu Activation",
     "location": "Addons Preferences",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "interface/viewport_pies.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/interface/viewport_pies.html",
     "category": "Interface"
     }
 
diff --git a/space_view3d_spacebar_menu/__init__.py b/space_view3d_spacebar_menu/__init__.py
index 51a7d4dd..0ac50e2d 100644
--- a/space_view3d_spacebar_menu/__init__.py
+++ b/space_view3d_spacebar_menu/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "location": "View3D > Spacebar",
     "description": "Object Mode Context Sensitive Spacebar Menu",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "interface/context_menu.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/interface/context_menu.html",
     "category": "Interface",
 }
 
diff --git a/space_view3d_stored_views/__init__.py b/space_view3d_stored_views/__init__.py
index 527ef040..6a174fdb 100644
--- a/space_view3d_stored_views/__init__.py
+++ b/space_view3d_stored_views/__init__.py
@@ -24,8 +24,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "View3D > Sidebar > View > Stored Views",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "3d_view/stored_views.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/3d_view/stored_views.html",
     "category": "3D View"
 }
 
diff --git a/sun_position/__init__.py b/sun_position/__init__.py
index 499cafc3..c1638ef6 100644
--- a/sun_position/__init__.py
+++ b/sun_position/__init__.py
@@ -38,8 +38,7 @@ bl_info = {
     "blender": (2, 80, 0),
     "location": "World > Sun Position",
     "description": "Show sun position with objects and/or sky texture",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "lighting/sun_position.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/lighting/sun_position.html",
     "category": "Lighting",
 }
 
diff --git a/system_blend_info.py b/system_blend_info.py
index b2e7b926..7f574cf7 100644
--- a/system_blend_info.py
+++ b/system_blend_info.py
@@ -28,8 +28,7 @@ bl_info = {
     "location": "Properties > Scene > Blend Info Panel",
     "description": "Show information about the .blend",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "system/blend_info.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/system/blend_info.html",
     "category": "System",
 }
 
diff --git a/system_demo_mode/__init__.py b/system_demo_mode/__init__.py
index f7cc7d7c..88a052f1 100644
--- a/system_demo_mode/__init__.py
+++ b/system_demo_mode/__init__.py
@@ -25,8 +25,7 @@ bl_info = {
     "location": "File > Demo Menu",
     "description": "Demo mode lets you select multiple blend files and loop over them.",
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "system/demo_mode.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/system/demo_mode.html",
     "support": 'OFFICIAL',
     "category": "System",
 }
diff --git a/system_property_chart.py b/system_property_chart.py
index 901d06ec..4eeeb48e 100644
--- a/system_property_chart.py
+++ b/system_property_chart.py
@@ -27,8 +27,7 @@ bl_info = {
     "description": ("Edit arbitrary selected properties for "
                     "objects/sequence strips of the same type"),
     "warning": "",
-    "doc_url": "https://docs.blender.org/manual/en/dev/addons/"
-               "system/property_chart.html",
+    "doc_url": "{BLENDER_MANUAL_URL}/addons/system/property_chart.html",
     "category": "System",
 }