The fix is to remove the call to bs.expandBy(v) and compute the radius directly. I believe this call was intended to be bs.expandRadiusBy(v), but it is superfluous when the radius is computed directly. " Merged from svn/trunk using: svn merge -r 10229:10230 http://www.openscenegraph.org/svn/osg/OpenSceneGraph/trunk/src/osgTerrain