I spent some time this weekend trying to get Maya to render it’s lighting to a texture.  There are countless resources out there for baking Direct Lighting or Ambient Occlusion but if you are looking to get Final Gather into your texture, the information tapers quickly.  I did find one way to make it happen, but it’s far from ideal.  This technique is only useful if you plan to render a simple model with local lighting, like a small detail object or vignette.  If you want to bake an entire scene this would get ugly…

Step 1: Populate the Final Gather Map

1. Open your scene and make sure that it renders as intended in your render window.
2. Go to Render Settings -> Render Using [ Mental Ray ].  Make sure you are using the correct renderer.  This is likely the case if #1 is rendering properly.
3. Now, in Render Settings -> Indirect Lighting -> Final Gather Map, set Rebuild to OFF.
4. Just below that Rebuild option should be “Final Gather File”.  Type in the name of a temp file that Mental Ray can use to store it’s cached samples.  Any name will do as long as you have write access.
5. I would also “Enable Map Visualizer” so you can see your sample points.
6. Now render the scene from multiple angles.  Each render of your scene will add more sample points.  You can see these being populated if you enabled map visualization.
7. Go back to “Rebuild” and change that value to FREEZE.  This will lock the Final Gather samples that you’ve collected, using them in your texture bake.

Step 2: Bake

Any baking that you do here (and in your preview renders) will reference the frozen file that you pre-constructed.

I won’t get into the details of how to bake because there are plenty of in-depth video tutorials on this part.  I only wanted to show that it is possible to use final gather in your light maps.  This approach however is not suited for large environment light baking…