==Armature==

Fix the roll mess in transform. Since roll is based on an automatically calculated up axis, transforming bones would mess up bone orientation. This code automatically adjusts the roll value to keep bone orientation as consistant as possible. That works all around in transform for all transformations.

Doesn't work with x-axis mirror though as that doesn't use transform elements (fixing it would be nice for later)

Most interesting is that it works with the mirror tool (obviously), so you don't have to fix all the rolls after mirroring one side of an armature.

It could be made an option if someone presents a good enough point for that, but I can't see why you'd want the previous mess instead.

NB: this also ports a utility fonction from etch-a-ton to set bone roll from an up axis.

source/blender/include/BIF_editarmature.h

@@ -68,6 +68,8 @@ typedef struct EditBone
 
 } EditBone;
 
+float	rollBoneToVector(EditBone *bone, float new_up_axis[3]);
+
 void	make_boneList(struct ListBase *list, struct ListBase *bones, EditBone *parent);
 void	editbones_to_armature (struct ListBase *list, struct Object *ob);
 

source/blender/include/transform.h

@@ -160,7 +160,7 @@ typedef struct TransData {
 	TransDataExtension *ext;	/* for objects, poses. 1 single malloc per TransInfo! */
 	TransDataIpokey *tdi;		/* for objects, ipo keys. per transdata a malloc */
 	TransDataCurveHandleFlags *hdata; /* for curves, stores handle flags for modification/cancel */
-	void *tdmir;		 /* mirrored element pointer, in editmode mesh to EditVert */
+	void  *extra;		 /* extra data (mirrored element pointer, in editmode mesh to EditVert) (editbone for roll fixing) (...) */
     short  flag;         /* Various flags */
 	short  protectflag;	 /* If set, copy of Object or PoseChannel protection */
 /*#ifdef WITH_VERSE*/

source/blender/src/editarmature.c

@@ -1817,6 +1817,31 @@ void deselectall_armature(int toggle, int doundo)
 	}
 }
 
+/* adjust bone roll to align Z axis with vector
+ * vec is in local space and is normalized
+ */
+float rollBoneToVector(EditBone *bone, float new_up_axis[3])
+{
+	float mat[3][3], nor[3], up_axis[3], vec[3];
+	float roll;
+
+	VecSubf(nor, bone->tail, bone->head);
+	
+	vec_roll_to_mat3(nor, 0, mat);
+	VECCOPY(up_axis, mat[2]);
+	
+	roll = NormalizedVecAngle2(new_up_axis, up_axis);
+	
+	Crossf(vec, up_axis, new_up_axis);
+	
+	if (Inpf(vec, nor) < 0)
+	{
+		roll = -roll;
+	}
+	
+	return roll;
+}
+
 /* Sets the roll value of selected bones, depending on the mode
  * 	mode == 0: their z-axes point upwards 
  * 	mode == 1: their z-axes point towards 3d-cursor

source/blender/src/transform_conversions.c

@@ -1133,6 +1133,14 @@ static void createTransArmatureVerts(TransInfo *t)
 					Mat3CpyMat3(td->smtx, smtx);
 					Mat3CpyMat3(td->mtx, mtx);
 
+					VecSubf(delta, ebo->tail, ebo->head);	
+					vec_roll_to_mat3(delta, ebo->roll, td->axismtx);
+
+					if ((ebo->flag & BONE_ROOTSEL) == 0)
+					{
+						td->extra = ebo;
+					}
+
 					td->ext = NULL;
 					td->tdi = NULL;
 					td->val = NULL;
@@ -1150,6 +1158,11 @@ static void createTransArmatureVerts(TransInfo *t)
 					Mat3CpyMat3(td->smtx, smtx);
 					Mat3CpyMat3(td->mtx, mtx);
 
+					VecSubf(delta, ebo->tail, ebo->head);	
+					vec_roll_to_mat3(delta, ebo->roll, td->axismtx);
+
+					td->extra = ebo; /* to fix roll */
+
 					td->ext = NULL;
 					td->tdi = NULL;
 					td->val = NULL;
@@ -1863,7 +1876,7 @@ static void VertsToTransData(TransData *td, EditVert *eve)
 	td->ext = NULL;
 	td->tdi = NULL;
 	td->val = NULL;
-	td->tdmir = NULL;
+	td->extra = NULL;
 	if (BIF_GetTransInfo()->mode == TFM_BWEIGHT) {
 		td->val = &(eve->bweight);
 		td->ival = eve->bweight;
@@ -2216,7 +2229,7 @@ static void createTransEditVerts(TransInfo *t)
 				/* Mirror? */
 				if( (mirror>0 && tob->iloc[0]>0.0f) || (mirror<0 && tob->iloc[0]<0.0f)) {
 					EditVert *vmir= editmesh_get_x_mirror_vert(G.obedit, tob->iloc);	/* initializes octree on first call */
-					if(vmir != eve) tob->tdmir = vmir;
+					if(vmir != eve) tob->extra = vmir;
 				}
 				tob++;
 			}

source/blender/src/transform_generics.c

@@ -254,7 +254,7 @@ static void editmesh_apply_to_mirror(TransInfo *t)
 		if (td->flag & TD_SKIP)
 			continue;
 		
-		eve = td->tdmir;
+		eve = td->extra;
 		if(eve) {
 			eve->co[0]= -td->loc[0];
 			eve->co[1]= td->loc[1];
@@ -470,6 +470,8 @@ void recalcData(TransInfo *t)
 		else if(G.obedit->type==OB_ARMATURE){   /* no recalc flag, does pose */
 			bArmature *arm= G.obedit->data;
 			EditBone *ebo;
+			TransData *td = t->data;
+			int i;
 			
 			/* Ensure all bones are correctly adjusted */
 			for (ebo=G.edbo.first; ebo; ebo=ebo->next){
@@ -506,6 +508,28 @@ void recalcData(TransInfo *t)
 					ebo->oldlength= ebo->length;
 				}
 			}
+			
+			/* fix roll */
+			for(i = 0; i < t->total; i++, td++)
+			{
+				if (td->extra)
+				{
+					float vec[3], up_axis[3];
+					float qrot[4];
+					
+					ebo = td->extra;
+					
+					VecSubf(vec, ebo->tail, ebo->head);
+					Normalize(vec);
+					RotationBetweenVectorsToQuat(qrot, td->axismtx[1], vec);
+					
+					VECCOPY(up_axis, td->axismtx[2]);
+					QuatMulVecf(qrot, up_axis);
+					
+					ebo->roll = rollBoneToVector(ebo, up_axis);
+				}
+			}
+			
 			if(arm->flag & ARM_MIRROR_EDIT) 
 				transform_armature_mirror_update();