adding 2 new functions

Mat3ToScalef and Mat4ToScalef

These return a floating point scale value which is the average of the 3 axies.
Use this to adjust curve radius when applying scale/rot

source/blender/blenlib/BLI_arithb.h

@@ -333,6 +333,9 @@ void MinMax3(float *min, float *max, float *vec);
 void SizeToMat3(float *size, float mat[][3]);
 void SizeToMat4(float *size, float mat[][4]);
 
+float Mat3ToScalef(float mat[][3]);
+float Mat4ToScalef(float mat[][4]);
+
 void printmatrix3(char *str, float m[][3]);
 void printmatrix4(char *str, float m[][4]);
 

source/blender/blenlib/intern/arithb.c

@@ -2866,6 +2866,25 @@ void Mat4ToSize( float mat[][4], float *size)
 	size[2]= VecLength(mat[2]);
 }
 
+/* this gets the average scale of a matrix, only use when your scaling
+ * data that has no idea of scale axis, examples are bone-envelope-radius
+ * and curve radius */
+float Mat3ToScalef(float mat[][3])
+{
+	/* unit length vector */
+	float unit_vec[3] = {0.577350269189626, 0.577350269189626, 0.577350269189626};
+	Mat3MulVecfl(mat, unit_vec);
+	return VecLength(unit_vec);
+}
+
+float Mat4ToScalef(float mat[][4])
+{
+	float tmat[3][3];
+	Mat3CpyMat4(tmat, mat);
+	return Mat3ToScalef(tmat);
+}
+
+
 /* ************* SPECIALS ******************* */
 
 void triatoquat( float *v1,  float *v2,  float *v3, float *quat)
@@ -3581,4 +3600,3 @@ void LocQuatSizeToMat4(float mat[][4], float loc[3], float quat[4], float size[3
 	mat[3][1] = loc[1];
 	mat[3][2] = loc[2];
 }
-

source/blender/src/editarmature.c

@@ -346,16 +346,11 @@ void apply_rot_armature (Object *ob, float mat[3][3])
 	ListBase	list;
 	EditBone *ebone;
 	bArmature *arm;
-	float scale;	/* store the scale of the matrix here to use on envelopes */
+	float scale = Mat3ToScalef(mat);	/* store the scale of the matrix here to use on envelopes */
 	arm = get_armature(ob);
 
-	if (!arm) {
-		return;
-	} else {
-		float tmp[3] = {1.0, 1.0, 1.0};
-		Mat3MulVecfl(mat, tmp);
-		scale = (fabs(tmp[0]) + fabs(tmp[1]) + fabs(tmp[2])) / 3.0f;
-	}
+	if (!arm)
+		return;	
 	
 	/* Put the armature into editmode */
 	list.first= list.last = NULL;
@@ -2653,22 +2648,13 @@ void add_verts_to_dgroups(Object *ob, Object *par, int heat, int mirror)
 	}
 
 	/* compute the weights based on gathered vertices and bones */
-	if (heat) {
+	if (heat)
 		heat_bone_weighting(ob, mesh, verts, numbones, dgrouplist, dgroupflip,
 			root, tip, selected);
-	} else {
-		float scale;
-		float tmp[3] = {1.0, 1.0, 1.0};
-		float mat[3][3];
-		
-		/* scale value from matrix, wont account for non uniform scale but ok */
-		Mat3CpyMat4(mat, par->obmat);
-		Mat3MulVecfl(mat, tmp);
-		scale = (fabs(tmp[0]) + fabs(tmp[1]) + fabs(tmp[2])) / 3.0f;
-		
+	else
 		envelope_bone_weighting(ob, mesh, verts, numbones, bonelist, dgrouplist,
-			dgroupflip, root, tip, selected, scale);
-	}
+			dgroupflip, root, tip, selected, Mat4ToScalef(par->obmat));
+	
     /* free the memory allocated */
     MEM_freeN(bonelist);
     MEM_freeN(dgrouplist);

source/blender/src/editobject.c

@@ -3728,7 +3728,9 @@ void apply_object()
 				where_is_object(ob);
 			}
 			else if ELEM(ob->type, OB_CURVE, OB_SURF) {
+				float scale;
 				object_to_mat3(ob, mat);
+				scale = Mat3ToScalef(mat);
 				cu= ob->data;
 				
 				if(cu->id.us>1) {
@@ -3749,6 +3751,7 @@ void apply_object()
 							Mat3MulVecfl(mat, bezt->vec[0]);
 							Mat3MulVecfl(mat, bezt->vec[1]);
 							Mat3MulVecfl(mat, bezt->vec[2]);
+							bezt->radius *= scale;
 							bezt++;
 						}
 					}