This is difficult to explain without a 3D diagram :P

Let's say there's a room that joins to a vertical tunnel, which 1024 units down has another room at 90 degrees - even though the rooms might not be visible to each other in game vis still treats them as if they are.

Another example - you've got a circular tube, hollow in the middle, without doors but it doesn't reach all the way to the roof (or sky) - everything outside it will be drawn the same, as long as it's not backfacing.

This was something from Q2, so maybe doesn't apply to Quake. 

What tool do I need to replace a BSP's textures?

I tried Wally and TexMex 

try again :P 

Invisible moving walls...

Possible? As far as I can tell movewalls need a visible object to move around, and noclip texture causes errors on compile. 

But I've never gotten it to work.

If you have a noclip brush inside a load of normal brushes (ie. they're on the outside of the func_) then the noclip will still push the player. 

I've managed to get it sort of working via extended movewalls :)
I don't need it to do too much, it's not actually pushing the player but monsters :E 

skip would work.

movewalls don't need a visible object.

clip only works if it's bounded by visible brushes (physics test box is determined by the outer extents of all visible brushes.) 

And download newskip.exe from a link provided by someone who knows where a copy is. Probably here:
http://www.quaddicted.com/tools/newskip.zip

Then run it after compiling your map, i.e.

"newskip mapname"

in a command prompt :S 

You mean Texmex can replace textures into a BSP?
Because I checked and it could only generate WADs with the new textures 

adquedit can replace bsp textures too, iirc.

it's really old though and has a very strange user interface. 

ok, so how do I do it?

In the file menu - TexMex can't export/save .BSPs

When I simply open a BSP with it and replace a texture then click save from the file menu, the opened BSP remains unchanged and TexMex creates a WAD with the modified level's textures 

just tried again to do it and i stand corrected. was sure i'd used it before for that :S

just tried adquedit and that works - basically it looks like you have to first find the textures you want to add in, and export them from wherever they are as .mip files (texmex can do this) then load the map you want to edit in adquedit, and choose 'replace mip', which lets you import a new .mip file

someone needs to remake adquedit :) 

someone needs to remake adquedit :)

yeah... i haven't touched it since it malfunctioned and deleted my whole quake directory. It was halfway through my quake2 directory when i hard-rebooted to stop the devastation.

FrikaC's Fimg has some of the capabilities. I haven't used it much, though.

I actually wrote some command-line "lmp2pcx" and "pcx2lmp" programs a few years ago (right after the adquedit disaster), perhaps i should release them. I also made spr2pcx, but when I got to trying to make a pcx2spr, i realized you actually need some extra metadata to generate the spr (i.e. sprite flags, frame groups, etc.) and sort of ran out of steam at that point. 

i wish i understood how to read files that weren't just plain text. i've wanted to do a sprite program since there are still things in fimg that aren't great.
for example, it's very difficult and lengthy to align sprite center points across multiple frames when the frame dimensions change. you basically have to wing it and do it by hand. 

If Texmex can't replace a BSP's textures, what should I use? Fimg?

As for adquedit,
replacing the .MIP files = replacing the BSP's textures? 

each .mip is one Quake texture. A .wad file comprises of several .mip files. A .mip contains an image of a texture, and it contains smaller simplified versions of the same texture, to save on memory when you are far away from a texture. So a 64x64 .mip contains a 32x32, a 16x16 and an 8x8 version of the same texture :)
You will see this effect if you work with Wally or TexMex (I think) and you just focus in on one texture. 

Are called mipmaps. 

thanks anyways guys - I've finally got it working 

"SubdivideFace: Didn't split the polygon near (-3232 -624 -208), twall2_5"

I broke it :( 

Which editor are you using?

Also:

http://user.tninet.se/~xir870k/tooltips.txt

Very useful.

Do a "check map for problems" in WC3.3.

Try and find any faces with daft texture dimensions. 

Doesn't come up with a brush problem in check for problems. Guess I'll just poke the textures as you said.

It's odd though. The section of map in question I made in a seperate file and copy/pasted over. Only broke when trying to compile after sewing it together. Was a lot of brushes though so I guess it just broke something :( 

and look for mis-aligned vertexes. 

For some reason a random face at the back of a func_train was 0.25 scale... 

...Fitzquake does have an entities limit :)

Have to cut my map in half :E 

raise max_edicts to a higher value.