Added function to blur3dhelper.  Also fixed a bug that wasn't correctly calculating preview mesh for prox vertex in some situations. 
Added function to blur3dhelper.  Also fixed a bug that wasn't correctly calculating preview mesh for prox vertex in some situations. 

git-svn-id: a3b746cc1383a42926249ed33eaccad697259b1b@16854 896c8824-d3f5-0310-9c61-ac502b9a79dc

blurstudio/cross3d