B-Bones: split the Scale In/Out properties into X and Y values.

As far as I can tell, there is no technical reason why the B-Bone
segment thickness scaling can't be separated into two axes. The
only downside is the increase in complexity of the B-Bone settings,
but this is inevitable due to the increase in flexibility.

Updating the file is somewhat complicated though, because F-Curves
and drivers have to be duplicated and updated to the new names.

Reviewers: campbellbarton

Subscribers: icappiello, jpbouza

Differential Revision: https://developer.blender.org/D4716

16 files changed, 225 insertions, 58 deletions

diff --git a/source/blender/blenkernel/BKE_armature.h b/source/blender/blenkernel/BKE_armature.h
index e171eec023f..366fdc0ce45 100644
--- a/source/blender/blenkernel/BKE_armature.h
+++ b/source/blender/blenkernel/BKE_armature.h
@@ -207,7 +207,7 @@ typedef struct BBoneSplineParameters {
   /* Control values. */
   float ease1, ease2;
   float roll1, roll2;
-  float scaleIn, scaleOut;
+  float scale_in_x, scale_in_y, scale_out_x, scale_out_y;
   float curveInX, curveInY, curveOutX, curveOutY;
 } BBoneSplineParameters;
 
diff --git a/source/blender/blenkernel/intern/action.c b/source/blender/blenkernel/intern/action.c
index 9ae8d27b27f..59e279d8054 100644
--- a/source/blender/blenkernel/intern/action.c
+++ b/source/blender/blenkernel/intern/action.c
@@ -458,7 +458,8 @@ bPoseChannel *BKE_pose_channel_verify(bPose *pose, const char *name)
   unit_axis_angle(chan->rotAxis, &chan->rotAngle);
   chan->size[0] = chan->size[1] = chan->size[2] = 1.0f;
 
-  chan->scaleIn = chan->scaleOut = 1.0f;
+  chan->scale_in_x = chan->scale_in_y = 1.0f;
+  chan->scale_out_x = chan->scale_out_y = 1.0f;
 
   chan->limitmin[0] = chan->limitmin[1] = chan->limitmin[2] = -M_PI;
   chan->limitmax[0] = chan->limitmax[1] = chan->limitmax[2] = M_PI;
@@ -1410,7 +1411,8 @@ void BKE_pose_rest(bPose *pose)
     pchan->curveInX = pchan->curveInY = 0.0f;
     pchan->curveOutX = pchan->curveOutY = 0.0f;
     pchan->ease1 = pchan->ease2 = 0.0f;
-    pchan->scaleIn = pchan->scaleOut = 1.0f;
+    pchan->scale_in_x = pchan->scale_in_y = 1.0f;
+    pchan->scale_out_x = pchan->scale_out_y = 1.0f;
 
     pchan->flag &= ~(POSE_LOC | POSE_ROT | POSE_SIZE | POSE_BBONE_SHAPE);
   }
@@ -1438,8 +1440,10 @@ void BKE_pose_copyesult_pchan_result(bPoseChannel *pchanto, const bPoseChannel *
   pchanto->curveOutY = pchanfrom->curveOutY;
   pchanto->ease1 = pchanfrom->ease1;
   pchanto->ease2 = pchanfrom->ease2;
-  pchanto->scaleIn = pchanfrom->scaleIn;
-  pchanto->scaleOut = pchanfrom->scaleOut;
+  pchanto->scale_in_x = pchanfrom->scale_in_x;
+  pchanto->scale_in_y = pchanfrom->scale_in_y;
+  pchanto->scale_out_x = pchanfrom->scale_out_x;
+  pchanto->scale_out_y = pchanfrom->scale_out_y;
 
   pchanto->rotmode = pchanfrom->rotmode;
   pchanto->flag = pchanfrom->flag;
diff --git a/source/blender/blenkernel/intern/armature.c b/source/blender/blenkernel/intern/armature.c
index b726ea6c20d..3dd655ee9a8 100644
--- a/source/blender/blenkernel/intern/armature.c
+++ b/source/blender/blenkernel/intern/armature.c
@@ -680,8 +680,10 @@ void BKE_pchan_bbone_spline_params_get(struct bPoseChannel *pchan,
       }
     }
 
-    param->scaleIn = bone->scaleIn * (!rest ? pchan->scaleIn : 1.0f);
-    param->scaleOut = bone->scaleOut * (!rest ? pchan->scaleOut : 1.0f);
+    param->scale_in_x = bone->scale_in_x * (!rest ? pchan->scale_in_x : 1.0f);
+    param->scale_in_y = bone->scale_in_y * (!rest ? pchan->scale_in_y : 1.0f);
+    param->scale_out_x = bone->scale_out_x * (!rest ? pchan->scale_out_x : 1.0f);
+    param->scale_out_y = bone->scale_out_y * (!rest ? pchan->scale_out_y : 1.0f);
 
     /* Extra curve x / y */
     param->curveInX = bone->curveInX + (!rest ? pchan->curveInX : 0.0f);
@@ -827,7 +829,8 @@ static void make_bbone_spline_matrix(BBoneSplineParameters *param,
                                      float pos[3],
                                      float axis[3],
                                      float roll,
-                                     float scalefac,
+                                     float scalex,
+                                     float scaley,
                                      float result[4][4])
 {
   float mat3[3][3];
@@ -843,8 +846,8 @@ static void make_bbone_spline_matrix(BBoneSplineParameters *param,
   }
 
   /* BBone scale... */
-  mul_v3_fl(result[0], scalefac);
-  mul_v3_fl(result[2], scalefac);
+  mul_v3_fl(result[0], scalex);
+  mul_v3_fl(result[2], scaley);
 }
 
 /* Fade from first to second derivative when the handle is very short. */
@@ -908,17 +911,25 @@ int BKE_pchan_bbone_spline_compute(BBoneSplineParameters *param,
 
     /* End points require special handling to fix zero length handles. */
     ease_handle_axis(bezt_deriv1[0], bezt_deriv2[0], axis);
-    make_bbone_spline_matrix(
-        param, scalemats, bezt_controls[0], axis, roll1, param->scaleIn, result_array[0].mat);
+    make_bbone_spline_matrix(param,
+                             scalemats,
+                             bezt_controls[0],
+                             axis,
+                             roll1,
+                             param->scale_in_x,
+                             param->scale_in_y,
+                             result_array[0].mat);
 
     for (int a = 1; a < param->segments; a++) {
       evaluate_cubic_bezier(bezt_controls, bezt_points[a], cur, axis);
 
       float fac = ((float)a) / param->segments;
       float roll = interpf(roll2, roll1, fac);
-      float scalefac = interpf(param->scaleOut, param->scaleIn, fac);
+      float scalex = interpf(param->scale_out_x, param->scale_in_x, fac);
+      float scaley = interpf(param->scale_out_y, param->scale_in_y, fac);
 
-      make_bbone_spline_matrix(param, scalemats, cur, axis, roll, scalefac, result_array[a].mat);
+      make_bbone_spline_matrix(
+          param, scalemats, cur, axis, roll, scalex, scaley, result_array[a].mat);
     }
 
     negate_v3(bezt_deriv2[1]);
@@ -928,7 +939,8 @@ int BKE_pchan_bbone_spline_compute(BBoneSplineParameters *param,
                              bezt_controls[3],
                              axis,
                              roll2,
-                             param->scaleOut,
+                             param->scale_out_x,
+                             param->scale_out_y,
                              result_array[param->segments].mat);
   }
   /* Other code (e.g. display) uses matrices for the segments themselves. */
@@ -942,9 +954,11 @@ int BKE_pchan_bbone_spline_compute(BBoneSplineParameters *param,
 
       float fac = (a + 0.5f) / param->segments;
       float roll = interpf(roll2, roll1, fac);
-      float scalefac = interpf(param->scaleOut, param->scaleIn, fac);
+      float scalex = interpf(param->scale_out_x, param->scale_in_x, fac);
+      float scaley = interpf(param->scale_out_y, param->scale_in_y, fac);
 
-      make_bbone_spline_matrix(param, scalemats, prev, axis, roll, scalefac, result_array[a].mat);
+      make_bbone_spline_matrix(
+          param, scalemats, prev, axis, roll, scalex, scaley, result_array[a].mat);
       copy_v3_v3(prev, cur);
     }
   }
diff --git a/source/blender/blenloader/intern/versioning_270.c b/source/blender/blenloader/intern/versioning_270.c
index bd405bd6410..20b2bfd95c8 100644
--- a/source/blender/blenloader/intern/versioning_270.c
+++ b/source/blender/blenloader/intern/versioning_270.c
@@ -256,8 +256,8 @@ static void do_version_action_editor_properties_region(ListBase *regionbase)
 static void do_version_bones_super_bbone(ListBase *lb)
 {
   for (Bone *bone = lb->first; bone; bone = bone->next) {
-    bone->scaleIn = 1.0f;
-    bone->scaleOut = 1.0f;
+    bone->scale_in_x = bone->scale_in_y = 1.0f;
+    bone->scale_out_x = bone->scale_out_y = 1.0f;
 
     do_version_bones_super_bbone(&bone->childbase);
   }
@@ -1338,8 +1338,8 @@ void blo_do_versions_270(FileData *fd, Library *UNUSED(lib), Main *bmain)
         if (ob->pose) {
           for (bPoseChannel *pchan = ob->pose->chanbase.first; pchan; pchan = pchan->next) {
             /* see do_version_bones_super_bbone()... */
-            pchan->scaleIn = 1.0f;
-            pchan->scaleOut = 1.0f;
+            pchan->scale_in_x = pchan->scale_in_y = 1.0f;
+            pchan->scale_out_x = pchan->scale_out_y = 1.0f;
 
             /* also make sure some legacy (unused for over a decade) flags are unset,
              * so that we can reuse them for stuff that matters now...
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index fbe0f70527b..73109cd9a6b 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -30,6 +30,7 @@
 #include "BLI_string.h"
 #include "BLI_utildefines.h"
 
+#include "DNA_anim_types.h"
 #include "DNA_object_types.h"
 #include "DNA_camera_types.h"
 #include "DNA_cloth_types.h"
@@ -56,11 +57,13 @@
 #include "DNA_text_types.h"
 
 #include "BKE_action.h"
+#include "BKE_animsys.h"
 #include "BKE_cloth.h"
 #include "BKE_collection.h"
 #include "BKE_constraint.h"
 #include "BKE_colortools.h"
 #include "BKE_customdata.h"
+#include "BKE_fcurve.h"
 #include "BKE_freestyle.h"
 #include "BKE_gpencil.h"
 #include "BKE_idprop.h"
@@ -621,6 +624,74 @@ static ARegion *do_versions_add_region(int regiontype, const char *name)
   return ar;
 }
 
+static void do_version_bones_split_bbone_scale(ListBase *lb)
+{
+  for (Bone *bone = lb->first; bone; bone = bone->next) {
+    bone->scale_in_y = bone->scale_in_x;
+    bone->scale_out_y = bone->scale_out_x;
+
+    do_version_bones_split_bbone_scale(&bone->childbase);
+  }
+}
+
+static bool replace_bbone_scale_rnapath(char **p_old_path)
+{
+  char *old_path = *p_old_path;
+
+  if (old_path == NULL) {
+    return false;
+  }
+
+  if (BLI_str_endswith(old_path, "bbone_scalein") ||
+      BLI_str_endswith(old_path, "bbone_scaleout")) {
+    *p_old_path = BLI_strdupcat(old_path, "x");
+
+    MEM_freeN(old_path);
+    return true;
+  }
+
+  return false;
+}
+
+static void do_version_bbone_scale_fcurve_fix(ListBase *curves, FCurve *fcu)
+{
+  /* Update driver variable paths. */
+  if (fcu->driver) {
+    LISTBASE_FOREACH (DriverVar *, dvar, &fcu->driver->variables) {
+      DRIVER_TARGETS_LOOPER_BEGIN (dvar) {
+        replace_bbone_scale_rnapath(&dtar->rna_path);
+      }
+      DRIVER_TARGETS_LOOPER_END;
+    }
+  }
+
+  /* Update F-Curve's path. */
+  if (replace_bbone_scale_rnapath(&fcu->rna_path)) {
+    /* If matched, duplicate the curve and tweak name. */
+    FCurve *second = copy_fcurve(fcu);
+
+    second->rna_path[strlen(second->rna_path) - 1] = 'y';
+
+    BLI_insertlinkafter(curves, fcu, second);
+
+    /* Add to the curve group. */
+    second->grp = fcu->grp;
+
+    if (fcu->grp != NULL && fcu->grp->channels.last == fcu) {
+      fcu->grp->channels.last = second;
+    }
+  }
+}
+
+static void do_version_bbone_scale_animdata_cb(ID *UNUSED(id),
+                                               AnimData *adt,
+                                               void *UNUSED(wrapper_data))
+{
+  LISTBASE_FOREACH_MUTABLE (FCurve *, fcu, &adt->drivers) {
+    do_version_bbone_scale_fcurve_fix(&adt->drivers, fcu);
+  }
+}
+
 void do_versions_after_linking_280(Main *bmain)
 {
   bool use_collection_compat_28 = true;
@@ -3203,6 +3274,32 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
       }
     }
 
+    /* Split bbone_scalein/bbone_scaleout into x and y fields. */
+    if (!DNA_struct_elem_find(fd->filesdna, "bPoseChannel", "float", "scale_out_y")) {
+      /* Update armature data and pose channels. */
+      LISTBASE_FOREACH (bArmature *, arm, &bmain->armatures) {
+        do_version_bones_split_bbone_scale(&arm->bonebase);
+      }
+
+      LISTBASE_FOREACH (Object *, ob, &bmain->objects) {
+        if (ob->pose) {
+          LISTBASE_FOREACH (bPoseChannel *, pchan, &ob->pose->chanbase) {
+            pchan->scale_in_y = pchan->scale_in_x;
+            pchan->scale_out_y = pchan->scale_out_x;
+          }
+        }
+      }
+
+      /* Update action curves and drivers. */
+      LISTBASE_FOREACH (bAction *, act, &bmain->actions) {
+        LISTBASE_FOREACH_MUTABLE (FCurve *, fcu, &act->curves) {
+          do_version_bbone_scale_fcurve_fix(&act->curves, fcu);
+        }
+      }
+
+      BKE_animdata_main_cb(bmain, do_version_bbone_scale_animdata_cb, NULL);
+    }
+
     /* Versioning code until next subversion bump goes here. */
   }
 }
diff --git a/source/blender/draw/intern/draw_armature.c b/source/blender/draw/intern/draw_armature.c
index 12d4ca95a39..bd2fa1d861d 100644
--- a/source/blender/draw/intern/draw_armature.c
+++ b/source/blender/draw/intern/draw_armature.c
@@ -1110,8 +1110,11 @@ static void ebone_spline_preview(EditBone *ebone, float result_array[MAX_BBONE_S
     param.roll1 += prev->roll2;
   }
 
-  param.scaleIn = ebone->scaleIn;
-  param.scaleOut = ebone->scaleOut;
+  param.scale_in_x = ebone->scale_in_x;
+  param.scale_in_y = ebone->scale_in_y;
+
+  param.scale_out_x = ebone->scale_out_x;
+  param.scale_out_y = ebone->scale_out_y;
 
   param.curveInX = ebone->curveInX;
   param.curveInY = ebone->curveInY;
diff --git a/source/blender/editors/armature/armature_add.c b/source/blender/editors/armature/armature_add.c
index 3b65f3a71ed..2e14595cf57 100644
--- a/source/blender/editors/armature/armature_add.c
+++ b/source/blender/editors/armature/armature_add.c
@@ -85,8 +85,10 @@ EditBone *ED_armature_ebone_add(bArmature *arm, const char *name)
   bone->curveOutY = 0.0f;
   bone->ease1 = 1.0f;
   bone->ease2 = 1.0f;
-  bone->scaleIn = 1.0f;
-  bone->scaleOut = 1.0f;
+  bone->scale_in_x = 1.0f;
+  bone->scale_in_y = 1.0f;
+  bone->scale_out_x = 1.0f;
+  bone->scale_out_y = 1.0f;
 
   return bone;
 }
@@ -996,8 +998,10 @@ static int armature_extrude_exec(bContext *C, wmOperator *op)
             newbone->curveOutY = ebone->curveOutY;
             newbone->ease1 = ebone->ease1;
             newbone->ease2 = ebone->ease2;
-            newbone->scaleIn = ebone->scaleIn;
-            newbone->scaleOut = ebone->scaleOut;
+            newbone->scale_in_x = ebone->scale_in_x;
+            newbone->scale_in_y = ebone->scale_in_y;
+            newbone->scale_out_x = ebone->scale_out_x;
+            newbone->scale_out_y = ebone->scale_out_y;
 
             BLI_strncpy(newbone->name, ebone->name, sizeof(newbone->name));
 
diff --git a/source/blender/editors/armature/armature_intern.h b/source/blender/editors/armature/armature_intern.h
index 09e4c1acae7..f5833e0d1e3 100644
--- a/source/blender/editors/armature/armature_intern.h
+++ b/source/blender/editors/armature/armature_intern.h
@@ -165,7 +165,8 @@ typedef struct tPChanFCurveLink {
   float curveInX, curveInY;
   float curveOutX, curveOutY;
   float ease1, ease2;
-  float scaleIn, scaleOut;
+  float scale_in_x, scale_in_y;
+  float scale_out_x, scale_out_y;
 
   /** copy of custom properties at start of operator (to be restored before each modal step) */
   struct IDProperty *oldprops;
diff --git a/source/blender/editors/armature/armature_utils.c b/source/blender/editors/armature/armature_utils.c
index b4e4396ce89..29e90ea672f 100644
--- a/source/blender/editors/armature/armature_utils.c
+++ b/source/blender/editors/armature/armature_utils.c
@@ -502,8 +502,10 @@ static EditBone *make_boneList_rec(ListBase *edbo,
     eBone->curveOutY = curBone->curveOutY;
     eBone->ease1 = curBone->ease1;
     eBone->ease2 = curBone->ease2;
-    eBone->scaleIn = curBone->scaleIn;
-    eBone->scaleOut = curBone->scaleOut;
+    eBone->scale_in_x = curBone->scale_in_x;
+    eBone->scale_in_y = curBone->scale_in_y;
+    eBone->scale_out_x = curBone->scale_out_x;
+    eBone->scale_out_y = curBone->scale_out_y;
 
     eBone->bbone_prev_type = curBone->bbone_prev_type;
     eBone->bbone_next_type = curBone->bbone_next_type;
@@ -712,8 +714,10 @@ void ED_armature_from_edit(Main *bmain, bArmature *arm)
     newBone->curveOutY = eBone->curveOutY;
     newBone->ease1 = eBone->ease1;
     newBone->ease2 = eBone->ease2;
-    newBone->scaleIn = eBone->scaleIn;
-    newBone->scaleOut = eBone->scaleOut;
+    newBone->scale_in_x = eBone->scale_in_x;
+    newBone->scale_in_y = eBone->scale_in_y;
+    newBone->scale_out_x = eBone->scale_out_x;
+    newBone->scale_out_y = eBone->scale_out_y;
 
     newBone->bbone_prev_type = eBone->bbone_prev_type;
     newBone->bbone_next_type = eBone->bbone_next_type;
diff --git a/source/blender/editors/armature/pose_transform.c b/source/blender/editors/armature/pose_transform.c
index 91f0bdc51ad..03984bfdbd8 100644
--- a/source/blender/editors/armature/pose_transform.c
+++ b/source/blender/editors/armature/pose_transform.c
@@ -170,15 +170,18 @@ static int apply_armature_pose2bones_exec(bContext *C, wmOperator *op)
       curbone->roll2 += pchan_eval->roll2;
       curbone->ease1 += pchan_eval->ease1;
       curbone->ease2 += pchan_eval->ease2;
-      curbone->scaleIn += pchan_eval->scaleIn;
-      curbone->scaleOut += pchan_eval->scaleOut;
+      curbone->scale_in_x *= pchan_eval->scale_in_x;
+      curbone->scale_in_y *= pchan_eval->scale_in_y;
+      curbone->scale_out_x *= pchan_eval->scale_out_x;
+      curbone->scale_out_y *= pchan_eval->scale_out_y;
 
       /* reset pose values */
       pchan->curveInX = pchan->curveOutX = 0.0f;
       pchan->curveInY = pchan->curveOutY = 0.0f;
       pchan->roll1 = pchan->roll2 = 0.0f;
       pchan->ease1 = pchan->ease2 = 0.0f;
-      pchan->scaleIn = pchan->scaleOut = 1.0f;
+      pchan->scale_in_x = pchan->scale_in_y = 1.0f;
+      pchan->scale_out_x = pchan->scale_out_y = 1.0f;
     }
 
     /* clear transform values for pchan */
@@ -406,8 +409,10 @@ static bPoseChannel *pose_bone_do_paste(Object *ob,
     pchan->roll2 = chan->roll2;
     pchan->ease1 = chan->ease1;
     pchan->ease2 = chan->ease2;
-    pchan->scaleIn = chan->scaleIn;
-    pchan->scaleOut = chan->scaleOut;
+    pchan->scale_in_x = chan->scale_in_x;
+    pchan->scale_in_y = chan->scale_in_y;
+    pchan->scale_out_x = chan->scale_out_x;
+    pchan->scale_out_y = chan->scale_out_y;
 
     /* paste flipped pose? */
     if (flip) {
@@ -654,8 +659,8 @@ static void pchan_clear_scale(bPoseChannel *pchan)
 
   pchan->ease1 = 0.0f;
   pchan->ease2 = 0.0f;
-  pchan->scaleIn = 1.0f;
-  pchan->scaleOut = 1.0f;
+  pchan->scale_in_x = pchan->scale_in_y = 1.0f;
+  pchan->scale_out_x = pchan->scale_out_y = 1.0f;
 }
 
 /* clear location of pose-channel */
diff --git a/source/blender/editors/armature/pose_utils.c b/source/blender/editors/armature/pose_utils.c
index 2b7bd9ea05a..4215c122917 100644
--- a/source/blender/editors/armature/pose_utils.c
+++ b/source/blender/editors/armature/pose_utils.c
@@ -121,8 +121,10 @@ static void fcurves_to_pchan_links_get(ListBase *pfLinks,
     pfl->curveOutY = pchan->curveOutY;
     pfl->ease1 = pchan->ease1;
     pfl->ease2 = pchan->ease2;
-    pfl->scaleIn = pchan->scaleIn;
-    pfl->scaleOut = pchan->scaleOut;
+    pfl->scale_in_x = pchan->scale_in_x;
+    pfl->scale_in_y = pchan->scale_in_y;
+    pfl->scale_out_x = pchan->scale_out_x;
+    pfl->scale_out_y = pchan->scale_out_y;
 
     /* make copy of custom properties */
     if (pchan->prop && (transFlags & ACT_TRANS_PROP)) {
@@ -265,8 +267,10 @@ void poseAnim_mapping_reset(ListBase *pfLinks)
     pchan->curveOutY = pfl->curveOutY;
     pchan->ease1 = pfl->ease1;
     pchan->ease2 = pfl->ease2;
-    pchan->scaleIn = pfl->scaleIn;
-    pchan->scaleOut = pfl->scaleOut;
+    pchan->scale_in_x = pfl->scale_in_x;
+    pchan->scale_in_y = pfl->scale_in_y;
+    pchan->scale_out_x = pfl->scale_out_x;
+    pchan->scale_out_y = pfl->scale_out_y;
 
     /* just overwrite values of properties from the stored copies (there should be some) */
     if (pfl->oldprops) {
diff --git a/source/blender/editors/include/ED_armature.h b/source/blender/editors/include/ED_armature.h
index 9fb8f1b1b04..6b3bbd11967 100644
--- a/source/blender/editors/include/ED_armature.h
+++ b/source/blender/editors/include/ED_armature.h
@@ -85,7 +85,8 @@ typedef struct EditBone {
   float curveOutX, curveOutY;
   float curveInX, curveInY;
   float ease1, ease2;
-  float scaleIn, scaleOut;
+  float scale_in_x, scale_in_y;
+  float scale_out_x, scale_out_y;
 
   /** for envelope scaling */
   float oldlength;
diff --git a/source/blender/makesdna/DNA_action_types.h b/source/blender/makesdna/DNA_action_types.h
index 49bd05913cd..26fe63ef951 100644
--- a/source/blender/makesdna/DNA_action_types.h
+++ b/source/blender/makesdna/DNA_action_types.h
@@ -320,7 +320,8 @@ typedef struct bPoseChannel {
   float curveInX, curveInY;
   float curveOutX, curveOutY;
   float ease1, ease2;
-  float scaleIn, scaleOut;
+  float scale_in_x, scale_in_y;
+  float scale_out_x, scale_out_y;
 
   /** B-Bone custom handles; set on read file or rebuild pose based on pchan->bone data. */
   struct bPoseChannel *bbone_prev;
diff --git a/source/blender/makesdna/DNA_armature_types.h b/source/blender/makesdna/DNA_armature_types.h
index 0b1bd23bd9c..c7a3c762b48 100644
--- a/source/blender/makesdna/DNA_armature_types.h
+++ b/source/blender/makesdna/DNA_armature_types.h
@@ -81,7 +81,8 @@ typedef struct Bone {
   float curveOutX, curveOutY;
   /** Length of bezier handles. */
   float ease1, ease2;
-  float scaleIn, scaleOut;
+  float scale_in_x, scale_in_y;
+  float scale_out_x, scale_out_y;
 
   /**  patch for upward compat, UNUSED!. */
   float size[3];
diff --git a/source/blender/makesdna/intern/dna_rename_defs.h b/source/blender/makesdna/intern/dna_rename_defs.h
index f36e24b2000..7b4362e35e9 100644
--- a/source/blender/makesdna/intern/dna_rename_defs.h
+++ b/source/blender/makesdna/intern/dna_rename_defs.h
@@ -58,6 +58,8 @@ DNA_STRUCT_RENAME(SpaceIpo, SpaceGraph)
 DNA_STRUCT_RENAME(SpaceOops, SpaceOutliner)
 DNA_STRUCT_RENAME_ELEM(BPoint, alfa, tilt)
 DNA_STRUCT_RENAME_ELEM(BezTriple, alfa, tilt)
+DNA_STRUCT_RENAME_ELEM(Bone, scaleIn, scale_in_x)
+DNA_STRUCT_RENAME_ELEM(Bone, scaleOut, scale_out_x)
 DNA_STRUCT_RENAME_ELEM(Camera, YF_dofdist, dof_distance)
 DNA_STRUCT_RENAME_ELEM(Camera, clipend, clip_end)
 DNA_STRUCT_RENAME_ELEM(Camera, clipsta, clip_start)
@@ -71,6 +73,8 @@ DNA_STRUCT_RENAME_ELEM(ParticleSettings, dup_ob, instance_object)
 DNA_STRUCT_RENAME_ELEM(ParticleSettings, dupliweights, instance_weights)
 DNA_STRUCT_RENAME_ELEM(View3D, far, clip_end)
 DNA_STRUCT_RENAME_ELEM(View3D, near, clip_start)
+DNA_STRUCT_RENAME_ELEM(bPoseChannel, scaleIn, scale_in_x)
+DNA_STRUCT_RENAME_ELEM(bPoseChannel, scaleOut, scale_out_x)
 DNA_STRUCT_RENAME_ELEM(bTheme, tact, space_action)
 DNA_STRUCT_RENAME_ELEM(bTheme, tbuts, space_properties)
 DNA_STRUCT_RENAME_ELEM(bTheme, tclip, space_clip)
diff --git a/source/blender/makesrna/intern/rna_armature.c b/source/blender/makesrna/intern/rna_armature.c
index d32e814f7f8..c397bb51713 100644
--- a/source/blender/makesrna/intern/rna_armature.c
+++ b/source/blender/makesrna/intern/rna_armature.c
@@ -671,24 +671,48 @@ void rna_def_bone_curved_common(StructRNA *srna, bool is_posebone)
   RNA_DEF_CURVEBONE_UPDATE(prop, is_posebone);
 
   /* Scale In/Out */
-  prop = RNA_def_property(srna, "bbone_scalein", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "scaleIn");
+  prop = RNA_def_property(srna, "bbone_scaleinx", PROP_FLOAT, PROP_NONE);
+  RNA_def_property_float_sdna(prop, NULL, "scale_in_x");
+  RNA_def_property_flag(prop, PROP_PROPORTIONAL);
   RNA_def_property_range(prop, 0.0f, 5.0f);
   RNA_def_property_float_default(prop, 1.0f);
-  RNA_def_property_ui_text(
-      prop,
-      "Scale In",
-      "Scale factor for start of the B-Bone, adjusts thickness (for tapering effects)");
+  RNA_def_property_ui_text(prop,
+                           "Scale In X",
+                           "X-axis scale factor for start of the B-Bone, "
+                           "adjusts thickness (for tapering effects)");
   RNA_DEF_CURVEBONE_UPDATE(prop, is_posebone);
 
-  prop = RNA_def_property(srna, "bbone_scaleout", PROP_FLOAT, PROP_NONE);
-  RNA_def_property_float_sdna(prop, NULL, "scaleOut");
+  prop = RNA_def_property(srna, "bbone_scaleiny", PROP_FLOAT, PROP_NONE);
+  RNA_def_property_float_sdna(prop, NULL, "scale_in_y");
+  RNA_def_property_flag(prop, PROP_PROPORTIONAL);
   RNA_def_property_range(prop, 0.0f, 5.0f);
   RNA_def_property_float_default(prop, 1.0f);
-  RNA_def_property_ui_text(
-      prop,
-      "Scale Out",
-      "Scale factor for end of the B-Bone, adjusts thickness (for tapering effects)");
+  RNA_def_property_ui_text(prop,
+                           "Scale In Y",
+                           "Y-axis scale factor for start of the B-Bone, "
+                           "adjusts thickness (for tapering effects)");
+  RNA_DEF_CURVEBONE_UPDATE(prop, is_posebone);
+
+  prop = RNA_def_property(srna, "bbone_scaleoutx", PROP_FLOAT, PROP_NONE);
+  RNA_def_property_float_sdna(prop, NULL, "scale_out_x");
+  RNA_def_property_flag(prop, PROP_PROPORTIONAL);
+  RNA_def_property_range(prop, 0.0f, 5.0f);
+  RNA_def_property_float_default(prop, 1.0f);
+  RNA_def_property_ui_text(prop,
+                           "Scale Out X",
+                           "X-axis scale factor for end of the B-Bone, "
+                           "adjusts thickness (for tapering effects)");
+  RNA_DEF_CURVEBONE_UPDATE(prop, is_posebone);
+
+  prop = RNA_def_property(srna, "bbone_scaleouty", PROP_FLOAT, PROP_NONE);
+  RNA_def_property_float_sdna(prop, NULL, "scale_out_y");
+  RNA_def_property_flag(prop, PROP_PROPORTIONAL);
+  RNA_def_property_range(prop, 0.0f, 5.0f);
+  RNA_def_property_float_default(prop, 1.0f);
+  RNA_def_property_ui_text(prop,
+                           "Scale Out Y",
+                           "Y-axis scale factor for end of the B-Bone, "
+                           "adjusts thickness (for tapering effects)");
   RNA_DEF_CURVEBONE_UPDATE(prop, is_posebone);
 
 #  undef RNA_DEF_CURVEBONE_UPDATE