I am having a lot of problems with parts of brushes disappearing in my map, I have no compile errors or errors being reported in hammer. Is it because my brushes are too complex? they don't seem to be too complex.

(hammer screenshot 1600x1200)

(in-game screenshot 1024x768)

allright I think you might have an invalid solid brush Have you checked for errors in hammer (alt+p)?

hehe lol I read over that you dont have errors in hammer sorry man!!!

Try deleting the brush and rebuilding it that worked for me sometimes when I get this problem.
A brush is alowed to have 32 faces (anyone may correct me if im wrong ) so I dont think thats the problem

It seems that you've rotated parts of your hallway. After doing this, some of the vertices aren't on the smallest possible grid (1x1) anymore. When compiling, the map gets exported as .map. Points not laying on the grid are moved to the nearest point on the grid, therefore you will get faces which are invalid and will cause trouble.

Try to adjust the vertices manually after rotating an object, in most cases this will work fine (Use the vertextool and just let the vertices snap to the nearest point and make sure, the lines are parallel in the different views.

thanks for the help/reply, hammer seems to do a lot of dumb things like this it seems.