If you check out id .plan files everyday to get the latest juicy info then you would have read Christian's .plan about using the "hint" texture to gain some speed performance, then this is quoted straight from his .plan so learn of a master and learn well :-)

Hint Brushes (a brush with a texture name of "hint") are a way of telling the viser to treat the contents of the brush as a seperate volume.
This is particularily usefull in forcing the viser to break the PVS in certain cases.

Given our Sample Area (Screenshot) , we can enable a feature of Quake II that the designers here at id have all grown to know and love, gl_showtris 1.
This tells Quake II to draw all the triangles which make up a scene (PLEASE NOTE: You will need a GL card with a full OpenGL implementation in order to use this feature.
This does not work on 3DFX.)

This is particularily usefull because you can see where the PVS breaks (if it breaks at all) in any given area, as well as showing you the complexity of ascene.
By turning on r_speeds 1 and gl_showtris 1 for the scene in our sample map, we see that the speeds run at a respectable 310 and we can see the triangles which make up the scene (Screenshot: 81k). Hardly in need of optimization but,
assuming that this was a horribly complex area...

What I would do in this case, is stick an 8 unit wide hint brush a ways into each left and right pipe, as well as the pipe which runs vertically through the floor.
This takes a bit of knowledge of how the vis process works and you have to sort of second-guess the engine as to what it might see from any given spot.
There is no "correct" way to do this, you sort of have to go on your gut feeling as to where to place the hint brushes (Editor Screenshot: 96k).

After re-bsping the map with hint brushes in place, we can see that we've shaved off 57 polygons (Screenshot: 77k) from that particular view.
Not a tremendous savings in this case, but sometimes it really makes a difference when you try to have your levels running at sub 600 poly scenes.

Go forth and experiment =)

by Christian Antkow

Well i hope you found that informative as i had no idea what they did until now :)