diff --git a/GUI/ba3d/model/object.cpp b/GUI/ba3d/model/object.cpp
index 67e1642929057e210bc73f98afbad913acee410f..189dc3415ff624b22c66c3f431dfa9c69f971b7d 100644
--- a/GUI/ba3d/model/object.cpp
+++ b/GUI/ba3d/model/object.cpp
@@ -107,7 +107,7 @@ const Geometry& Object::geo()
 
 void Object::draw(Canvas& canvas)
 {
-    if (isNull)
+    if (!valid())
         return;
 
     canvas.draw(color(), matrix(), geo());
diff --git a/GUI/ba3d/model/object.h b/GUI/ba3d/model/object.h
index 7e4885a6f59b65ae4af8d7cc9b9151891ca1f6e5..bf1a4bc2c41e42264c96a5b7669035f62a6cc37b 100644
--- a/GUI/ba3d/model/object.h
+++ b/GUI/ba3d/model/object.h
@@ -43,6 +43,7 @@ public:
     void addExtrinsicRotation(F3 turn, F3 scale, F3& rotate, F3 rotateExtrinsic, F3& translate);
     void setColor(QColor color) { m_color = color; }
 
+    bool valid() const { return !isNull; }
     const Geometry& geo();
     const QMatrix4x4& matrix() const { return m_matrix; }