Hello everyone! I am very new to Houdini an need some help. I am trying to rebuild ""FLUID SOURCE" node with container settings "collision" to use it later in DOP with "Smoke Solver" and importing collision with "Source Volume". Just now have made with VDB surface field called it "collision" and create one more VDB from attribute "v" called it "collisionvel". I see difference between FLUID SOURCE and VDB collision is in first one create 3 scalar velocity fields and the second create one vector velocity field. Setup with VDB now have a problem my density ( made with "Source Volume") : theres no adding to density from SOP , but it works like copy. I will appreciate for any help! Thanks! P.S. Also i am interesting to rebuild it all without smoke solver, so feel free to comment all around this problem!