Simple example, I have a brush against the skybox wall. Since nobody can see the back or bottom of said brush, it should be nodraw. What if however, I have 2 brushes next to the first, aligned on the side. One goes from the ground to the middle of the original, while the second goes from 3/4 of the original height to up past it. Since nobody can see the areas where brush number 1 touches the other two, in theory those parts should be nodraw. But that would involve cutting up your 3 brushes into 6. My crude picture; | | | | | | | | | | | | | | As opposed to; | | ---- | | | | | | ---- | | ---- | | | | So which is better? In the first, you'll have textures being drawn that cannot be seen. While in the second, you have removed the excess textures in favor of chopping up the brushes like sushi. Provided the brushes line up (edges touching) the visleafs should be exactly the same. Which leads back to the original question, lol. How much of this is worth it for nodraw/hiding unseen textures?