fix transform by instance, also make it take potentially different ad…

…ditional trafos into account
klocs · Dec 2, 2019 · 852fb80 · 852fb80
1 parent 794b3a1
commit 852fb80
Showing 1 changed file with 23 additions and 5 deletions.
diff --git a/xs/src/libslic3r/Model.cpp b/xs/src/libslic3r/Model.cpp
@@ -860,13 +860,31 @@ ModelObject::transform_by_instance(ModelInstance instance, bool dont_translate)
 {
     // We get instance by copy because we would alter it in the loop below,
     // causing inconsistent values in subsequent instances.
-    TransformationMatrix trafo = instance.get_trafo_matrix(dont_translate);
+    TransformationMatrix temp_trafo = instance.get_trafo_matrix(dont_translate);
+
+    this->apply_transformation(temp_trafo);
+
+    temp_trafo = temp_trafo.inverse();
 
+    /*
+      Let:
+        * I1 be the trafo of the given instance, 
+        * V the originial volume trafo and
+        * I2 the trafo of the instance to be updated
+      
+      Then:
+        previous: T = I2 * V
+        I1 has been applied to V:
+            Vnew = I1 * V
+            I1^-1 * I1 = eye
+
+            T = I2 * I1^-1 * I1 * V
+                ----------   ------
+                   I2new      Vnew
+    */
+
     for (ModelInstance* i : this->instances) {
-        i->rotation -= instance.rotation;
-        i->scaling_factor /= instance.scaling_factor;
-        if (!dont_translate)
-            i->offset.translate(-instance.offset.x, -instance.offset.y);
+        i->set_complete_trafo(i->get_trafo_matrix().multiplyRight(temp_trafo));
     }
     this->origin_translation = Pointf3(0,0,0);
     this->invalidate_bounding_box();