i just chose unity as my game engine an i don't like the level editor, and i really enjoy gtkradiant, its really easy and fun to use. I was wondering if someone knows a way i can use my gtkradiant levels in unity, since i know gtkradiant is meant for id tech 3, but i heard there is some way you can import your radiant levels to unity, does anyone know how? also, if you guys dont know how, can you please tell me how to get id tech 3? i would enjoy using that engine knowing how great the graphics can be if you mod it the right way.
We have been using our own "hacked up" fork of GtkRadiant for a long time and we use it with a number of game engines. You might be interested in it: http://thamessoftware.co.uk/openradiant/
It is still free and open-source but it treats art assets like a standard modeller (i.e not from Quake III specific pk3 files). It also exports directly to .obj (for intergration with the rest of your art pipeline) and exports / exposes all the entities in a simple parseable file.
Finally it also provides some basic lightmap baking and optionally extends the .obj format to include lightmap coordinates. However you could also just export without lightmaps and use Maya, Blender, UE4, Unity etc to do its own.
Hope this helps.
The Id tech engine uses a fundamentally different data structure to store scene data than Unity does which means you can't just move scene files between engines. Based on the little bit of digging I did you would have to export to something like Maya and then into Unity. You may also want to check out Pro Builder. It works right in the Unity editor but works a lot like the Radiant/Hammer editor.