Is it possible to edit multiple objects uv maps in the same time without joining them into same object?
texture atlas addon?
How to use it?
Get your coffee. Here’s Gleb showing how to unwrap a game level, in less than 2.5 minutes.
Here’s the BA thread.
https://blenderartists.org/forum/showthread.php?265750-TextureAtlas-create-LightMaps-ShadowMaps-for-entire-scene&highlight=texture+atlas