Do BSP holes exist in the Q3 engine?

(damocles) #1

I am expriencing a problem that if this was the unreal 1 engine, I’d expect it, but I never thought it happened in the Q3 engine - BSP holes. In unreal, this is a problem during compile caused by some random placement of brushes and it causes sections of the map to pop in and out of existence depending upon where the player stands in the BSP tree. I am getting this repeatedly on my map, observe…

My normal view

if I take one step forwards, I get this:

Huge sections of the map don’t get drawn. It’s not like it’s one triangle or similar, it’s one whole BSP chunk that doesn’t get drawn.

I ran brush cleanup and there are no warnings or errors during compile. This is happening in various unrelated locations (there were 4 different spots I found on my last compile) and sometimes they will be there and then the next compile they are gone even though nothing has changed.

So is this a known problem or what? What the hell can I do to fix it?

(kat) #2

I used to keep getting this easrly on with my SP maps and it turned out to be one of the transparent shaders not having the ‘nonsolid’ shader parameter… it’s since been fixed but it took ages to figure out what was happening (It usually happened when placing the cobweb texture on a nodraw brush, the maps used to have holes in them where the nodraw penatrated the walls, doing excactly what you posted above…)

I’ve also had that happen with missplaced hint brushes which sometimes cause odd splits in the BSP that don’t get rendered… if you’ve got hints in place try moving or deleting them or shifting that section of the map a bit…

(damocles) #3

Did that effect happen locally to the solid nodraw brushes, or was it random all over the map?

(kat) #4

locally in both cases

(damocles) #5

Dang, then I don’t think it’s that. The scene above has no nodraw brushes (other than caulk) in the area. That and I’ve only used standard shaders for nodraw stuff.

hmm.

(kat) #6

is it a lot of work for you to try and change the dimentions of that passage slightly so compiling splits the BSP in a different way (or move the caulk hull walls if you’ve got them in that area)?? see if that helps… I’ve done this once or twice and it usually fixes the problem if plan of action ‘A’ and/or ‘B’ didn’t work

(damocles) #7

I keep doing that. So far I’ve had to completely rebuild 4 different areas of the map because of this problem. And bizarrely it seems to fix the problem for about 10 compiles. After that it will surface somewhere else. Sometimes it comes back with reinforcements too :frowning:

I would rather find the cause of the problem than keep trying to work around it.

(ReBoOt) #8

well i’ve had this error myself it’s usually just one brush that’s the problem moving it or resize it might help. if the brushes doesnt face "the void - u know the gray stuff :slight_smile: " you can make them detail and then your problems will be gone.

(kat) #9

A couple more things you could take a look at… switch on ‘view blocks’ (the blue blocksize grid) and see where that section is in relation to the blocksize grid, whilst not a solution in itself it does give you a general clue as to how BSP is splitting the BSP when it looks at the brushwork in relation to the main BSP block.

Have you tried loading in the portal file and taking a look in camera view for anything that looks ‘odd’? Just do a BSP compile as that’s saves the *.prt file and then load that in GTK… if you’ve got tri-souped or 3pt clipped brushwork in your map (lookslike you have…!) you increase the chance of this happening unfortunatly and as you’re finding out now it can be a real arse to fix…

(damocles) #10

I tried that too, the portals look normal, nothing that would suggest a problem. I might try rearranging things, maybe adding as hint to control the splits more…

I don’t have any 3-point editing, only vertex editing. And I’m very careful to control vertex edits - only ever on 3-sided faces, and only ever on one axis at a time (z-axis usually).

(ydnar) #11

Check any special shaders you might be using nearby, such as clip, hint, flames, cobwebs, etc.

We cleaned the Wolf shaders used in ET, but some errors might have slipped through. Notably, a lot of the RTCW flame shaders were neither translucent nor nonsolid, predicably leading to all kinds of weird interactions.

y