Dear all, This sort of relates to my current wip and an odd problem I am having, however I'm posting here rather than the wip as I hope any answers may help others. The problem is that a normal Vvis compile does not appear to be sorting out the vis leaves in a way I would expect. When I switch Mat_wireframe to 1 I get models etc rendered even though I am 'looking' through world geometry. In the above, image 1 is looking down a corridor to the outside. I'd kind of expect there to be models etc rendered here as the end of the corridor is open (no hint or area portals) Each subsequent image is taken a few steps to the right of the last. In 2 the models etc have gone. I'd expect this, the wall is world geometry. 3 has be baffled. The models are back but the whole room is made with world brushes. The door at the end leads to a small room, also made entirely of world brushes. 4 is how I expected 3 to be, all I have done is moved to the right. There are no leaks or other errors so has anybody any idea what is going on? FInally how do I fix it? Do I just need to add a hit brush at the end of the corridor in 1, or should it be an area portal? Hope someone can help.