Fix T69536: Setting dimensions for parented objects fails

Parenting/constraints/delta-scaled all caused setting dimensions to fail.

Take the difference between the input scale and final scale into
account when applying the dimensions.

1 files changed, 33 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index ed517bfc513..acfa6085d45 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -2799,6 +2799,12 @@ void BKE_object_boundbox_calc_from_mesh(struct Object *ob, struct Mesh *me_eval)
   ob->runtime.bb->flag &= ~BOUNDBOX_DIRTY;
 }
 
+/* -------------------------------------------------------------------- */
+/** \name Object Dimension Get/Set
+ *
+ * \warning Setting dimensions is prone to feedback loops in evaluation.
+ * \{ */
+
 void BKE_object_dimensions_get(Object *ob, float vec[3])
 {
   BoundBox *bb = NULL;
@@ -2818,7 +2824,19 @@ void BKE_object_dimensions_get(Object *ob, float vec[3])
   }
 }
 
-void BKE_object_dimensions_set(Object *ob, const float value[3], int axis_mask)
+/**
+ * The original scale and object matrix can be passed in so any difference
+ * of the objects matrix and the final matrix can be accounted for,
+ * typically this caused by parenting, constraints or delta-scale.
+ *
+ * Re-using these values from the object causes a feedback loop
+ * when multiple values are modified at once in some situations. see: T69536.
+ */
+void BKE_object_dimensions_set_ex(Object *ob,
+                                  const float value[3],
+                                  int axis_mask,
+                                  const float ob_scale_orig[3],
+                                  const float ob_obmat_orig[4][4])
 {
   BoundBox *bb = NULL;
 
@@ -2832,7 +2850,16 @@ void BKE_object_dimensions_set(Object *ob, const float value[3], int axis_mask)
 
     for (int i = 0; i < 3; i++) {
       if (((1 << i) & axis_mask) == 0) {
+
+        if (ob_scale_orig != NULL) {
+          const float scale_delta = len_v3(ob_obmat_orig[i]) / ob_scale_orig[i];
+          if (isfinite(scale_delta)) {
+            len[i] *= scale_delta;
+          }
+        }
+
         if (len[i] > 0.0f) {
+
           ob->scale[i] = copysignf(value[i] / len[i], ob->scale[i]);
         }
       }
@@ -2840,6 +2867,11 @@ void BKE_object_dimensions_set(Object *ob, const float value[3], int axis_mask)
   }
 }
 
+void BKE_object_dimensions_set(Object *ob, const float value[3], int axis_mask)
+{
+  BKE_object_dimensions_set_ex(ob, value, axis_mask, NULL, NULL);
+}
+
 void BKE_object_minmax(Object *ob, float min_r[3], float max_r[3], const bool use_hidden)
 {
   BoundBox bb;