I started a quick and dirty custom lightmapper project just for fun some time ago. The idea was to make a simple alternative to rendering in external programs for Unity free users. I thought this might be useful for someone else too so the tool can be downloaded from the link below:
https://dl.dropboxusercontent.com/u/4320246/LightmapTool/LightmapTool.unitypackage
It’s slow and its clunky but it somewhat works At least for me its a good alternative to external modeling software since you don’t have to export anything or match lighting and materials in Blender/3ds max/whatever every time you want to see some results.
However it really is slow (~2-4k pixels / sec) and I wouldn’t recommend using it for large scenes with lots of LM surfaces.
If you don’t want to convert .tiff files to .exr manually, then you’ll also need to download free HDR tools from here: HDR Tools
After lightmapping is complete, you get a number of .tiff files and a .bat file. The bat file should convert tiffs to exr files automatically. The bat file needs to know hdr_create.exe’s location so you’ll have to set that before you bake.
PLEASE MAKE SURE YOU’VE BACKUPPED YOUR FILES BEFORE USING THIS TOOL. USE IT AT YOUR OWN RISK!
I have to put the above disclaimer because I haven’t tested the tool very well and it does overwrite any files without asking if they are named similarly (for example LightmapFar-0.tiff or .exr). It’s also possible that the script fails somehow to name files correctly and ends up overwriting wrong files. These shouldn’t happen but there is always a risk
There should be a tutorial image inside the package on how to set things up. You do most of this only once per scene.
Note that the tool only runs in play mode instead of being an editor script. This is because I’d like to have a farm of webplayers build my lightmaps on multiple computers in the future. I don’t want to instal unity on all my computers
Below are some quick and dirty test renders. Nothing fancy, but the point is that there is actual indirect lighting going on and that it was rendered using Unity free.
Webplayer example:
https://dl.dropboxusercontent.com/u/4320246/LightmapTool/LightmapExample/LightmapExample.html
Some not so fancy screen shots: