Strange Request: JK2 Map Format

[mcmonkey]

Can anyone help me understand JK2's .map file format?

Specifically, the brushes. I can't seem to identify how the numbers in the brush definition correlate to the actual brush. I assumed at first they were vertices, but then several vertices would be well outside the brush itself.

So... I don't even know what to think. How is the brush format designed?

 

 

A brush def, for reference, would be like this example:

 

// brush 0

{

( -64 64 0 ) ( -64 64 8 ) ( -64 -64 8 ) skylands/wall1 0 0 0 0.250000 0.250000 0 0 0

( -64 64 8 ) ( -64 64 0 ) ( 64 64 0 ) skylands/wall1 0 0 0 0.250000 0.250000 0 0 0

( 64 -72 8 ) ( 64 64 8 ) ( 64 64 0 ) skylands/wall1 0 0 0 0.250000 0.250000 0 0 0

( -48 -64 8 ) ( 72 -64 8 ) ( 72 -64 0 ) skylands/wall1 0 0 0 0.250000 0.250000 0 0 0

( -56 -72 8 ) ( -56 64 8 ) ( 64 64 8 ) skylands/wall1 0 0 0 0.250000 0.250000 0 0 0

( 64 64 0 ) ( -56 64 0 ) ( -56 -72 0 ) skylands/wall1 0 0 0 0.250000 0.250000 0 0 0

}

 

I don't get why it has things like 72 and -56 and etc. when it's corners are at 64/-64/0/8, no other points.

[mcmonkey]

Update:

I've determined the sides of the box:

 

( 64 64 -64 ) ( -64 64 -64 ) ( -64 -64 -64 ) bottom 0 0 0 0.250000 0.250000 0 0 0

( -64 -64 64 ) ( -64 64 64 ) ( 64 64 64 ) top 0 0 0 0.250000 0.250000 0 0 0

( -64 -64 8 ) ( 64 -64 8 ) ( 64 -64 0 ) yminus 0 0 0 0.250000 0.250000 0 0 0

( 64 -64 8 ) ( 64 64 8 ) ( 64 64 0 ) xplus 0 0 0 0.250000 0.250000 0 0 0

( 64 64 8 ) ( -64 64 8 ) ( -64 64 0 ) yplus 0 0 0 0.250000 0.250000 0 0 0

( -64 64 8 ) ( -64 -64 8 ) ( -64 -64 0 ) xminus 0 0 0 0.250000 0.250000 0 0 0

and discovered that if you only read the relevant digits: the Z's for top/bottom, the Y digits from Y+/Y-, and the X digits from X+/X-, you can build a reasonably accurate cuboid representing the object... this doesn't explain what the extra digits are for, or how to read more complex shapes.

[acdcfanbill]

JK2 and JKA share the the Q3 map format with a few caveats I assume. Here's some info on Quake3 and the original Quake .map files.

 

There's obviously been some updates to the format since Quake era, I don't think Quake supported patches? anyway, it should help a bit.