Hello,
I’ve been searching through all of the 28 pages of this forum but haven’t found anything related to the questions I’m having. What I wanted to find out is:
1. Can Q3 BSP levels (user created levels, I’m 100% sure that original ID levels can’t) be legally used at all in a projects outside of the Q3?
2. If they can be used, how can I contact specific creator of the level, most of the levels that can be downloaded here have email removed notification in their readme file?
I’m a micro-indie-game-developer in a sense that I’m as indie as indie can get and I wanted to include few of the users custom Q3 levels in my game. My game has no similarity with Quake or any other ID concept, it’s a small TP RPG style adventure game that I’m developing in CopperCube engine. CopperCube can import Q3 BSP levels together with level’s lightmaps and the stylish geometry approach of the levels is incredibly compelling to me.
If someone is interested to see the game you can check the YT video here: youtu.be/5Wvm1RXdkd0
...or go to the temporary development-site I’ve created about a week ago here: aziellachronicles.weebly.com
The game is a 0.0.2 version, so it’s a total work-in-progress stage but there are 3 levels + menu & intro in a windows build that can be downloaded and played.
Cheers!

If you are meaning to take some maps from here and port their geometry into a whole other game, I'd say it's a bit of a grey area. You'd definitely want to contact the map authors first (though I wouldn't be surprised if half of the emails you find are closed by now). You can find an author's email in the readme file in downloaded zips. Many readme files have the obligatory "do not distribute or modify in anyway" disclaimer, so you'd probably be out of luck in those cases. You would also have to be careful with textures/models/sounds/other assets - if some maps use vanilla id textures or textures from other authors, things get more complicated.

Personally I wouldn't recommend grabbing maps from here and sticking them in your own game, you should probably just create your own levels from scratch.

Thanks for reply, I never thought of checking the readme file email in zip, always thought it contained the same text as the one on a level page.
Yes, the idea was to use bsp file (geometry, textures & lightmaps) but to replace textures with my game's texture-set. All other features (triggers, events, sounds...) are not compatible with CopperCube and can't be used.
I've seen disclaimers on some map-pages but if map is a creator's property than, I guess, creator can allow further usage of the map in other games. If map's geometry & lightmap files are considered creators property and not ID's.
I've downloaded GTK Radiant 1.6.6 from 2018. and it seems fairly straightforward, it's just that I never modeled with it before, I mostly use Blender, 3DGS WED, DeleD, Gile[s], FragMotion & SH3D. I could learn to use it but I'm not sure if I would ever learn to mimic the Q3 level style, it's very specific approach to modeling that I never done before. Actually I think it's very rare to see that visual/geometrical approach except in older ID games or copycat projects.

GTKRadiant isn't really modelling software, it's a level design tool similar to something like QuArK or Hammer. However in your case, you would sort of be using it as a modelling tool. Why not just use Blender instead? It would probably be more straightforward and less of a hassle to export.

All of my releases can be used if you wish. I even include the .map file in most, if not all of my releases and state that the levels can be used in the readme files. lvlworld.com/author/Tigger-oN

There are a number of other releases that also do this too. You will need to check the readme files or contact the authors. As pointed out by Gooball, the email address is only blanked out on the version displayed on the site (to prevent spam), but are in the readme files in the download.

There is an old "open source" project that was long abandoned here : lvl.sourceforge.net/lvl-ogsl.php - that includes a number of releases that have been publicly released "open". While the project is no longer maintained, the few files are still available for download an use.

A quick search for source file or map source returns a few maps lvlworld.com/search/source%20file and lvlworld.com/search/map%20source

@Tig thank you so much, this is very generous of you, I've downloaded and looked closely through your levels, they are amazing! I especially liked One Down, Out On A Limb & Tig's Den. The Certain Ruin is the best thing, five levels that are extremely well done, some of them are perfect for any kind of game.
I don't know, it's just something about this visual approach to levels that is very good, it seems like a halfway between classic and modern 3D, it has a surreal feel to it but it's still functional, and simplified geometry is never overly simple, it doesn't make environment look ugly but it makes it very artistic & exploratory.
Thank you also for the OGSL links & for source/map references, I focused on BSP in my searches but should have focused on MAP files since they represent the author's intent to make levels usable to other creators.
@Gooball Blender has a very different approach to lightmaps, you need to create second UV set manually by unwrapping parts of the geometry and than bake lights for each part. GTKRadiant seems to be very close to 3DGS WED, which is also a level design tool, they both have automatic texture placements (similar to Radiant brushes I guess) and they generate lightmaps through their compile method.

Glad you were able to find some maps to work with. I see why Blender would be tougher to use since you want to preserve lightmaps. I definitely agree with your taste in Quake 3's style - even though it's old, I still think some maps can look heaps better than more modern engines. Some maps have an atmosphere that just can't be beat by any other game in my opinion.

Another wrench in this is that most levels for Q3 are developed with a SDK that have strict usage rights (i.e. "Only for use with the full commercial version of Quake III Arena") and then there's the fact the provided map models from the SDK - which are definitely copyrighted id property - get integrated into map compiles.
Edited 1.07 minutes after the original posting.

@leilei I didn't realize that but, now that I think about it, Q3 SDK injection into Q3 levels does make complete sense since it's, as Gooball pointed, actually a level editor not a modeling tool. I'm not sure what you mean by 'provided map models'? When I import BSP file into CopperCube only things that get imported are geometry (basic), textures and lightmaps. By basic geometry I mean files that are triangle-based static shapes, none of the effects, shaders or advanced instances are imported, not even doors/gates functionality. That is a problem in most cases since 70% of the levels have missing parts that break visual consistency of the map (missing parts of the wall, big/small holes on the floor...) but it does makes me confidant that only 3D classic geometry parts of the level are imported.
I'm guessing that for creators that would like to have full level/gameplay functionality of the Q3 map this would be a showstopper, which is a shame because I believe that enough time has passed, any game projects based on Q3 SDK would only be beneficial to Q3 community, in a sense that would only spark more interest in going back to Q3 content.
@gooball Yes, I'm very grateful to Tig for making his levels open and for giving me pointers on how to find similar maps. Blender is an extremely powerful tool but it's very difficult to stay low-poly with it or to have some sort of automatic lightmap-system. Everything related to baking the lights has to be done manually. ...which is good since it gives much more options and lights in the end-model can be spectacular but it's not what I need in this case :)
Edited 1.37 minutes after the original posting.