What does the 'hint' texture do?

[TheCoolDog]

What does the 'hint' texture do?

[Chef-Killer]

With correct placed hint brushes you can optimize the VIS'ing process of your map, e.g. to reduce r_speeds. But note that you could get the opposite effect if you place them in an incorrect way.

[jitspoe]

https://developer.valvesoftware.com/wiki/Hint_brush
http://tremmapping.pbworks.com/w/page/22453205/Understanding%20Vis%20and%20Hint%20Brushes

In short, hint brushes will (usually) break the map up more, thus adding more polygons, but, if placed correctly, will better define areas that have visibility blocked, so you won't render areas that are not actually visible.

Best way to tell if you need hint brushes is to vis your map normally, type "gl_showtris 1" at the console, and see if there are parts of the map that are visible even though they are blocked by solid walls.