diff --git a/src/ofxProjectionEditor.cpp b/src/ofxProjectionEditor.cpp
index 6c49856..b1c7bc1 100644
--- a/src/ofxProjectionEditor.cpp
+++ b/src/ofxProjectionEditor.cpp
@@ -59,6 +59,17 @@ void ofxProjectionEditor::updateJoints()
     }
 }
 
+void ofxProjectionEditor::moveSelectedSurface(ofVec2f by)
+{
+    if ( surfaceManager == NULL ) return;
+    if ( surfaceManager->getSelectedSurface() == NULL ) return;
+    vector<ofVec3f>& vertices = surfaceManager->getSelectedSurface()->getVertices();
+    for (int i=0; i<vertices.size(); i++) {
+        vertices[i] += by;
+    }
+    updateJoints();
+}
+
 bool ofxProjectionEditor::hitTestJoints(ofVec2f pos)
 {
     for ( int i=0; i<joints.size(); i++ ) {
diff --git a/src/ofxProjectionEditor.h b/src/ofxProjectionEditor.h
index d2b6a80..8da6693 100644
--- a/src/ofxProjectionEditor.h
+++ b/src/ofxProjectionEditor.h
@@ -15,6 +15,7 @@ public:
     void clearJoints();
     void createJoints();
     void updateJoints();
+    void moveSelectedSurface(ofVec2f by);
     bool hitTestJoints(ofVec2f pos);
     
 private:
diff --git a/src/ofxSurfaceManagerGui.cpp b/src/ofxSurfaceManagerGui.cpp
index 89aa4cd..39b4b8f 100644
--- a/src/ofxSurfaceManagerGui.cpp
+++ b/src/ofxSurfaceManagerGui.cpp
@@ -114,11 +114,7 @@ void ofxSurfaceManagerGui::mouseDragged(ofMouseEventArgs &args)
         ofVec2f mousePosition = ofVec2f(args.x, args.y);
         ofVec2f distance = mousePosition - clickPosition;
         // add this distance to all vertices in surface
-        vector<ofVec3f>& vertices = surfaceManager->getSelectedSurface()->getVertices();
-        for ( int i=0; i<vertices.size(); i++ ) {
-            vertices[i] += distance;
-        }
-        projectionEditor.updateJoints();
+        projectionEditor.moveSelectedSurface(distance);
         clickPosition = mousePosition;
     }
 }