The uFlex is not integrated with Unity's collision system. You can get the contact points and planes via flexGetContacts() and then use unity Physics to check for collision with game objects. Just add this to the Pull data method in the FlexSolver. I will add this to v0.5. Please refer to Flex manual for explanation of Flex's collision system. This should work, I will double check though. Haven't tested the shaders with the transparencies to be honest. Will have a look into this as well. This is on the ToDo list. I have some memory problems with the PInvoke, which I need to sort out. The only non-screen space solution for fluids, which I am aware of, are well known marching cubes. Its GPU version can be reasonably fast but it suffers from some visual artefacts. See the video: I can add it to later version of uFlex though.