diff --git a/components/nifosg/controller.cpp b/components/nifosg/controller.cpp
index eca5a7d79..76d3c5e62 100644
--- a/components/nifosg/controller.cpp
+++ b/components/nifosg/controller.cpp
@@ -364,6 +364,7 @@ AlphaController::AlphaController()
 
 AlphaController::AlphaController(const AlphaController &copy, const osg::CopyOp &copyop)
     : osg::NodeCallback(copy, copyop), ValueInterpolator(), Controller(copy)
+    , mData(copy.mData)
 {
 }