diff --git a/src/Mod/Raytracing/App/LuxFeature.cpp b/src/Mod/Raytracing/App/LuxFeature.cpp
index 9a963768d4..930fe12b7b 100644
--- a/src/Mod/Raytracing/App/LuxFeature.cpp
+++ b/src/Mod/Raytracing/App/LuxFeature.cpp
@@ -52,6 +52,17 @@ LuxFeature::LuxFeature(void)
     ADD_PROPERTY(Transparency,(0));
 }
 
+short LuxFeature::mustExecute() const
+{
+    if (Source.isTouched())
+        return 1;
+    if (Color.isTouched())
+        return 1;
+    if (Transparency.isTouched())
+        return 1;
+    return RaySegment::mustExecute();
+}
+
 App::DocumentObjectExecReturn *LuxFeature::execute(void)
 {
     std::stringstream result;
diff --git a/src/Mod/Raytracing/App/LuxFeature.h b/src/Mod/Raytracing/App/LuxFeature.h
index 469c0d1772..3fb30981ad 100644
--- a/src/Mod/Raytracing/App/LuxFeature.h
+++ b/src/Mod/Raytracing/App/LuxFeature.h
@@ -53,6 +53,7 @@ public:
 
     /** @name methods override Feature */
     //@{
+    short mustExecute() const;
     /// recalculate the Feature
     App::DocumentObjectExecReturn *execute(void);
 
diff --git a/src/Mod/Raytracing/App/RayFeature.cpp b/src/Mod/Raytracing/App/RayFeature.cpp
index 413b369518..cdd2cb6dc1 100644
--- a/src/Mod/Raytracing/App/RayFeature.cpp
+++ b/src/Mod/Raytracing/App/RayFeature.cpp
@@ -50,6 +50,17 @@ RayFeature::RayFeature(void)
     ADD_PROPERTY(Transparency,(0));
 }
 
+short RayFeature::mustExecute() const
+{
+    if (Source.isTouched())
+        return 1;
+    if (Color.isTouched())
+        return 1;
+    if (Transparency.isTouched())
+        return 1;
+    return RaySegment::mustExecute();
+}
+
 App::DocumentObjectExecReturn *RayFeature::execute(void)
 {
     std::stringstream result;
diff --git a/src/Mod/Raytracing/App/RayFeature.h b/src/Mod/Raytracing/App/RayFeature.h
index f0f2af933f..33d7e9f146 100644
--- a/src/Mod/Raytracing/App/RayFeature.h
+++ b/src/Mod/Raytracing/App/RayFeature.h
@@ -53,6 +53,7 @@ public:
 
     /** @name methods override Feature */
     //@{
+    short mustExecute() const;
     /// recalculate the Feature
     App::DocumentObjectExecReturn *execute(void);