this might be simple problem for you mappers to answer, not sure.
the first problem is with end capping, is there a way to make all of the sides visible? if you don't know what i mean take a look at the photos.the first one shows a normal highlighted rectangle. the next shows what happens when i use end-cap

the second problem is that I don't know how to make models (such as map objects) into a solid (so players wont go through it)