Rigify: refactor leg to make modifying the foot roll mechanism easier.

3 files changed, 24 insertions, 11 deletions

diff --git a/rigify/rig_ui_template.py b/rigify/rig_ui_template.py
index 06ff7faf..528a732c 100644
--- a/rigify/rig_ui_template.py
+++ b/rigify/rig_ui_template.py
@@ -130,6 +130,11 @@ def convert_pose_matrix_via_rest_delta(mat, from_bone, to_bone):
     return mat @ from_bone.bone.matrix_local.inverted() @ to_bone.bone.matrix_local
 
 
+def convert_pose_matrix_via_pose_delta(mat, from_bone, to_bone):
+    """Convert pose of one bone to another bone, preserving the current pose difference between them."""
+    return mat @ from_bone.matrix.inverted() @ to_bone.matrix
+
+
 def get_local_pose_matrix(pose_bone):
     """ Returns the local transform matrix of the given pose bone.
     """
diff --git a/rigify/rigs/limbs/leg.py b/rigify/rigs/limbs/leg.py
index 5967dcef..635250d6 100644
--- a/rigify/rigs/limbs/leg.py
+++ b/rigify/rigs/limbs/leg.py
@@ -232,7 +232,7 @@ class Rig(BaseLimbRig):
     @stage.parent_bones
     def parent_ik_toe_control(self):
         if self.use_ik_toe:
-            self.set_bone_parent(self.bones.ctrl.ik_toe, self.bones.mch.heel[2])
+            self.set_bone_parent(self.bones.ctrl.ik_toe, self.get_mch_heel_toe_output())
 
     @stage.configure_bones
     def configure_ik_toe_control(self):
@@ -247,6 +247,9 @@ class Rig(BaseLimbRig):
     ####################################################
     # Heel roll MCH
 
+    def get_mch_heel_toe_output(self):
+        return self.bones.mch.heel[-3]
+
     @stage.generate_bones
     def make_roll_mch_chain(self):
         orgs = self.bones.org.main
@@ -322,7 +325,7 @@ class Rig(BaseLimbRig):
     def parent_fk_parent_bone(self, i, parent_mch, prev_ctrl, org, prev_org):
         if i == 3:
             if not self.use_ik_toe:
-                align_bone_orientation(self.obj, parent_mch, self.bones.mch.heel[2])
+                align_bone_orientation(self.obj, parent_mch, self.get_mch_heel_toe_output())
 
                 self.set_bone_parent(parent_mch, prev_org, use_connect=True)
             else:
@@ -334,7 +337,7 @@ class Rig(BaseLimbRig):
     def rig_fk_parent_bone(self, i, parent_mch, org):
         if i == 3:
             if not self.use_ik_toe:
-                con = self.make_constraint(parent_mch, 'COPY_TRANSFORMS', self.bones.mch.heel[2])
+                con = self.make_constraint(parent_mch, 'COPY_TRANSFORMS', self.get_mch_heel_toe_output())
 
                 self.make_driver(con, 'influence', variables=[(self.prop_bone, 'IK_FK')], polynomial=[1.0, -1.0])
 
diff --git a/rigify/rigs/limbs/limb_rigs.py b/rigify/rigs/limbs/limb_rigs.py
index 2e6fe538..ddcccd4d 100644
--- a/rigify/rigs/limbs/limb_rigs.py
+++ b/rigify/rigs/limbs/limb_rigs.py
@@ -1026,32 +1026,37 @@ class RigifyLimbIk2FkBase:
             mat = convert_pose_matrix_via_rest_delta(mat, ik, ctrl)
             set_transform_from_matrix(obj, ctrl.name, mat, keyflags=keyflags)
 
+    def assign_extra_controls(self, context, obj, all_matrices, ik_bones, ctrl_bones):
+        for extra in self.extra_ctrl_list:
+            set_transform_from_matrix(
+                obj, extra, Matrix.Identity(4), space='LOCAL', keyflags=self.keyflags
+            )
+
     def apply_frame_state(self, context, obj, all_matrices):
         ik_bones = [ obj.pose.bones[k] for k in self.ik_bone_list ]
         ctrl_bones = [ obj.pose.bones[k] for k in self.ctrl_bone_list ]
         tail_bones = [ obj.pose.bones[k] for k in self.tail_bone_list ]
 
-        assert len(all_matrices) == len(ik_bones) + len(tail_bones)
+        assert len(all_matrices) >= len(ik_bones) + len(tail_bones)
 
         matrices = all_matrices[0:len(ik_bones)]
         tail_matrices = all_matrices[len(ik_bones):]
 
         use_pole = self.get_use_pole(obj)
 
+        # Remove foot heel transform, if present
+        self.assign_extra_controls(context, obj, all_matrices, ik_bones, ctrl_bones)
+
+        context.view_layer.update()
+
         # Set the end control position
-        endmat = convert_pose_matrix_via_rest_delta(matrices[-1], ik_bones[-1], ctrl_bones[-1])
+        endmat = convert_pose_matrix_via_pose_delta(matrices[-1], ik_bones[-1], ctrl_bones[-1])
 
         set_transform_from_matrix(
             obj, self.ctrl_bone_list[-1], endmat, keyflags=self.keyflags,
             undo_copy_scale=True,
         )
 
-        # Remove foot heel transform, if present
-        for extra in self.extra_ctrl_list:
-            set_transform_from_matrix(
-                obj, extra, Matrix.Identity(4), space='LOCAL', keyflags=self.keyflags
-            )
-
         # Set the base bone position
         ctrl_bones[0].matrix_basis = Matrix.Identity(4)