Follow up (bugfix) of 0d70a2be69

GLIndexedVertexArray newly uses Eigen::AlignedBox<float, 3>
for efficiency instead of our double based BoundingBoxf3.

src/slic3r/GUI/3DScene.hpp

@@ -356,6 +356,7 @@ public:
         if (! this->indexed_vertex_array.bounding_box().isEmpty()) {
             out.min = this->indexed_vertex_array.bounding_box().min().cast<double>();
             out.max = this->indexed_vertex_array.bounding_box().max().cast<double>();
+            out.defined = true;
         };
         return out;
     }