View Full Version : Rich, Question about your detail/structual brush tutorial

06-22-2002, 01:41 AM
If my entire map is in a skybox, then it isn't touching the "void" right? So I make all my brushes detail brushes? Is there a fast way to do this if I haven't be doing it from the begining?

06-22-2002, 01:49 AM
Very bad idea. Detail brushes dont block the -vis process. So, if you make your entire map in detail brushes, the entire level is always rendered by the game. This would mean absolute death for your framerate if you had a very large and detailed level.

06-22-2002, 01:51 AM
Which ones do I make detail brushes then? I don't quite understand how to choose.

06-22-2002, 04:44 AM
Ok, let me try to explain it to you.

First of all, try to think like the quake3 engine. The Q3 engine splits the world up in nodes(try to see it as big cubes). Players in JK2 are standing inside a node. If the player stands in node A, the engine is going to render all the nodes that node A can see. See means in this case that if at least 1 point of a node can see at least 1 point of another node by drawing a straight line .
Suppose the world is split in 9 nodes by 6 STRUCTURAL pillars (drawn as points below). Structural means that we tell the compiler that this brush, a pillar in this case, must split up the bsp tree. Now, If I draw straight lines from A it will render all nodes ABCDEFGHI, if I draw a straight line from I it will still be able to see ABCDEFGH since there is no structural brush blocking it => engine will render all the nodes


Structural brushes tell the engine : you cannot see through this wall. Again, seeing in the meaning of the q3 engine, and not as in the stuff you see on your screen. Now, these pillars are splitting the bsp tree, while there actually is no need for that => compile process will go slower. So what is the solution => make the pillars detail => engine will not split it up :


Everything will be node a, the engine will still render the same parts, but the vis process in the compilation will have taken less time.

When to use structural brushes : for the major layout of your map. The outer walls of the main structures should all be structural, and of course, the walls touching the void need to be structural as well.

Hope this clarifies it a little more.

06-22-2002, 04:55 AM
That was the most confusing thing I've ever read. (no offense) :p

If my entire map is in a skybox
This statement worries me. First of all, you're talking about frogger, I assume? You don't have a physical box surrounding the whole level do you?

Assuming you DON'T, let me ask you this question. Is the skybox a brush? No it's not. :)

Everything outside any area physically accessible by the player (i.e. outside of the brush referencing your sky) is considered the void. The fact that you have a skybox being drawn in the background does not prevent it from being the void.

06-22-2002, 05:36 AM
Now I'm really confused. This is what I did to make my sky box.

I drew a brush that encased my entire map (w/ extra room), then I hollowed it (I know, i know, I should make it by hand instead of hollowing it) then I selected all the peices and applied the "bespin" sky to it. It looks fine in game, am I doing this wrong?

06-22-2002, 05:56 AM

Quite possibly the best article on the subject ever; be sure to read part2 as well..