One of the SU videos might help - I think it's called 'inference locking'.

hi Raymond, @rvdkruk75 said: I can't find a shadow catching material for v-ray for SU. Do you have a link or something? in fact i searched about this problem and found video demonstrate this link for Video : http://www.youtube.com/watch?v=ZMpME8wlA-c Important note : this method works only when i use Hdri in environment slots as he did, but it didn't work with me when i used dome light with Hdri, and i don't know the solution to use it with dome light. maybe someone can find a solution for that.