diff --git a/parser/nodes.cc b/parser/nodes.cc
index e940673..ba934b9 100644
--- a/parser/nodes.cc
+++ b/parser/nodes.cc
@@ -9,6 +9,35 @@
 
 using namespace std;
 
+void Node::evaluateChildren(refptr<Node> parent)
+{
+    /* recursively evaluate all children nodes */
+    for (std::vector< refptr<Node> >::iterator it = m_children.begin();
+         it != m_children.end();
+         it++)
+    {
+        refptr<Node> evaluated = (*it)->evaluate();
+        if ( ! evaluated.isNull() )
+        {
+            if (typeid(*evaluated) == typeid(EvaluatePropagateNode))
+            {
+                for (vector<NodeRef>::iterator it2
+                        = evaluated->getChildren().begin();
+                     it2 != evaluated->getChildren().end();
+                     it2++)
+                {
+                    parent->addChild(*it2);
+                }
+            }
+            else
+            {
+                (*it)->evaluateChildren(evaluated);
+                parent->addChild(evaluated);
+            }
+        }
+    }
+}
+
 void Node::addChildren(NodeRef other)
 {
     if (other.isNull())
diff --git a/parser/nodes.h b/parser/nodes.h
index fa2716c..aed4e41 100644
--- a/parser/nodes.h
+++ b/parser/nodes.h
@@ -44,21 +44,7 @@ class Node
             std::cerr << "Warning: Node::evaluate() called!" << std::endl;
             return NULL;
         }
-        virtual void evaluateChildren(refptr<Node> parent)
-        {
-            /* recursively evaluate all children nodes */
-            for (std::vector< refptr<Node> >::iterator it = m_children.begin();
-                 it != m_children.end();
-                 it++)
-            {
-                refptr<Node> evaluated = (*it)->evaluate();
-                if ( ! evaluated.isNull() )
-                {
-                    (*it)->evaluateChildren(evaluated);
-                    parent->addChild(evaluated);
-                }
-            }
-        }
+        virtual void evaluateChildren(refptr<Node> parent);
 
         virtual bool isShape() { return false; }
         virtual bool isMaterial() { return false; }