Fix normal transform orientation calculation

When using the 'normal' orientation, the normal would be ignored
if the plane couldn't be calculated.

Now use only the normal if the plane is zero length,
this was already done, just not in all cases.

2 files changed, 8 insertions, 6 deletions

diff --git a/source/blender/editors/transform/transform.h b/source/blender/editors/transform/transform.h
index 5f738804579..d53f51f5076 100644
--- a/source/blender/editors/transform/transform.h
+++ b/source/blender/editors/transform/transform.h
@@ -796,6 +796,8 @@ bool applyTransformOrientation(const struct bContext *C, float mat[3][3], char r
 #define ORIENTATION_VERT	2
 #define ORIENTATION_EDGE	3
 #define ORIENTATION_FACE	4
+#define ORIENTATION_USE_PLANE(ty) \
+	ELEM(ty, ORIENTATION_NORMAL, ORIENTATION_EDGE, ORIENTATION_FACE)
 
 int getTransformOrientation_ex(const struct bContext *C, float normal[3], float plane[3], const short around);
 int getTransformOrientation(const struct bContext *C, float normal[3], float plane[3]);
diff --git a/source/blender/editors/transform/transform_orientations.c b/source/blender/editors/transform/transform_orientations.c
index c38fb15fc89..1c5a6eabd6f 100644
--- a/source/blender/editors/transform/transform_orientations.c
+++ b/source/blender/editors/transform/transform_orientations.c
@@ -796,12 +796,7 @@ int getTransformOrientation_ex(const bContext *C, float normal[3], float plane[3
 						}
 					}
 
-					if (is_zero_v3(plane)) {
-						result = ORIENTATION_VERT;
-					}
-					else {
-						result = ORIENTATION_EDGE;
-					}
+					result = ORIENTATION_EDGE;
 				}
 				else if (em->bm->totvertsel > 3) {
 					BMIter iter;
@@ -1104,6 +1099,11 @@ void ED_getTransformOrientationMatrix(const bContext *C, float orientation_mat[3
 
 	type = getTransformOrientation_ex(C, normal, plane, around);
 
+	/* Fallback, when the plane can't be calculated. */
+	if (ORIENTATION_USE_PLANE(type) && is_zero_v3(plane)) {
+		type = ORIENTATION_VERT;
+	}
+
 	switch (type) {
 		case ORIENTATION_NORMAL:
 			if (createSpaceNormalTangent(orientation_mat, normal, plane) == 0) {