I read in the radiant manual that you could detail brushes as long as they were not part of the outside wall. If used on an outside wall it would generate errors on compile.
How far can you go with making brushes detail?

You can go as far as you like but heed this warning:

The detail brushes speed up compiling the same way the fast vis option does..

The engine will 'ignore' the brushes meaning that it always draws them, regardless of how far away the player is, or what's blocking the view.

so for ex...

If you have an outdoor map with different buildings in it, make the outside walls to each building structural brushes..

the inside walls of the building and any furniture and stuff.. go ahead and make those detail..

The struc walls will stop the engine from rendering the inside of the house until player gets to a point they can see inside which will then 'pop up' everything at once.

Personally, I've never really understand why the need for detail brushes other than compile times.

So you're saying don't even bother? I am, for all intents and purposes, still new to mapping -- and learning more advanced techniques in both general practice, and specific engine/editor functions, all the time. If you think that using details brushes is a waste of time, I'll take your word for it. My goal is to be as 'quality and professional' as possible, without doing things that are a waste of time. ;)

According to the radiant manaul detail brushes can reduce frame rate and like you said compile time. I had 16 sets of stairs and they were creating havoc with the compile time. I was advised to make them detail which seemed to help. The map I was about to trash compiled one time in about an hour. Added some brushes to it and later it was a lot more than an hour. Of course my building techniques (Newbie) were not very good. On advice I made all the stairs detail and went crazy with the caulk gun. lol. It really seemed to help. Wish we could get some more input on this subject. Thanks brutus and N for your input. ;)

This is as far as I understand it:

Detail brushes are always rendered and do not exhibit the same 'pop-up' characteristics that the structural ones do. The reason for the pop-up effect comes in the VIS part of the compile.

Detail brushes are ignored by the vis process, meaning the engine will always 'see' these brushes.

That means in the case of your stairs they would definatly help as the engine doesn't have to decide 16 times (for 16 stairs) at which point they'll be drawn.

The drawback comes from going crazy with them or using them for only reducing compiling times.

If you use detail brushes as your entire map for ex.. the engine will always have to drawn every square inch all the time.. (BIG fps hit)

For all intents and purposes, I would throw out the use of them..

Use the caulk and the _nodraw wherever you can.. these help enormously.

Lol.. enough babbling for now tho :smokin:

Doesn't sound like babbling, sounds like great advice. I've just been making 'garbage' maps to test various techniques and things on -- and I'll say that I think using the caulk gun wisely benefits more than the detail. As you said, Brutus, in some cases like the stairs, the detail brush might help because it doesn't have to decide when to draw all that stuff. Also, I've been messing around with area portals, and while I haven't really mastered their use yet, it seems like you can really speed up some areas by 'sectioning' them off behind doors of curved walls, and setting up area portals thusly.