there are three stages that are important for us in urban terror: BSP; VIS; LIGHT. BSPC does not count as we will not play with bots...
BSP is the making of the mapfile itself
VIS calculates the different "rooms" you can see depending on where you stand, all what you can see will be rendered, relates to FPS and playability
LIGHT calculates the lighting your map does have.

use q3map2 to (de)compile maps... or better 27's hacked version: FS_q3map_Radbump_2a
http://forums.urbanterror.net ... go search 27's big thread, there it is.
and howto integrate it into the radiant: (so no frontend or commandline usage is needed)

for 1.5 are two ways...
place the compiler FS_q3map_Radbump_2a.exe into your radiant folder and rename it to q3map2.exe
(there should be already a q3map2.exe, rename that one before^^)

OR if you want to have the luxus of several different compilers being able to use from within your radiant:
close the radiant in case it is open.
open the following file with an editor:
for enlish windoze it should be similar to this:
c:documents and settings<username>preferences?RadiantSettings1.5.0q3.gamebuild_menu.xml
(IIRC)
better back the file up before... and have your radiant closed while doing all this!
paste:
between the first defined variable (defining "q3map2") and the first set of build commands (<build name="...).
safe file and close editor.

start the radiant.
now you can use both compilers by setting a different shortcut under "Build">>"Customize..." in your radiant..
i.e. [FS_q3map_Radbump_2a] -meta "[MapFile]" etc instead of [q3map2] -meta "[MapFile]"
if you would need to use the old one just change the the line back to [q3map2]

for 1.4:
somewhere in the urt.net forums there is a description...



you can set q3map2toolz (or any other frontend you are using) or radiant up, so it will automatically start urban terror after it has finished compiling.
q3maptoolz: via a checkbox somewhere
radiant: under options, press P, goto "Build", "Run Engine After Compile"

no matter how you do it, now go and BUILD!

q3map2 wiki, all the compile stage switches: http://en.wikibooks.org/wiki/Q3Map2

lists of error messages:
also on http://www.urbanterror.net .... (...)
http://www.lucasforums.com/showthread.php?t=125242
http://www.katsbits.com/htm/tutorials/common_error_messages.php?subaction=showfull&id=1149147724&archive=&start_from=&ucat=15&

decompiling:
use a frontend... or a START>>RUN/Ausführen>>cmd
<your path to the compiler>q3map2.exe -convert -format map <path to map><map>.bsp
in the folder where the .bsp was located you should find an new file: <mapname>_converted.map

#######################################################

when you want to playtest a map, you will need sv_pure 0 set in urbanterror, because of the .bsp file is not put into a .pk3 mapfile, pure servers wont work. and bombmode is g_gametype 8 by the way, and restart works via map_restart.

how to make a .pk3 : <placeholder> <---- here will be the link sometime in the future, as soon as i know everything and i am about to release ut4_de_train_rc1 ...

#######################################################

another program for decompiling: http://www.vgpro.com/file/16538_matchstick101.zip.html
dont know why i posted the last link, but it will stay... maybe was a decompiler for halflife...

this is what tub (devteam mapper) uses for compiling...

good tutorial:
http://www.leveldk.co.uk/tut8.htm

my current set:

BSP: -meta -patchmeta -v
VIS: -vis -hint -merge -saveprt -v
LIGHT: -light -fast -filter -patchshadows -gamma 1.5 -pointscale 1 -sky 1.7 -samples 3 -bounce 2 -v

having huge compile times?