diff --git a/src/osgTerrain/Layer.cpp b/src/osgTerrain/Layer.cpp
index 0f95d5de4..81de5eac9 100644
--- a/src/osgTerrain/Layer.cpp
+++ b/src/osgTerrain/Layer.cpp
@@ -563,5 +563,6 @@ unsigned int ProxyLayer::getModifiedCount() const
 osg::BoundingSphere ProxyLayer::computeBound(bool treatAsElevationLayer) const
 {
     if (_implementation.valid()) return _implementation->computeBound(treatAsElevationLayer);
+    else return osg::BoundingSphere();
 }