Recently I had to optimize rendering for a large project featuring several animated characters.
The project used final gather to create bounce lights.
Initially I thought that baking final gather at a set number of frames with the ‘Optimize for Animations’ option turned on would be sufficient.
Render Settings > mental ray > Indirect Lighting > Final Gathering Tracing > Optimize for Animations.
I couldn’t have been more wrong, the characters moved in and out of shadows and the flickering was awful.
Enter the solution: Animation Snapshots!
Animation Snapshots will create a duplicate of your model at set ranges, so if you have a sequence of a hundred frames and create an animation snapshot for frames 1-10-20 etc and bake final gather once, you will have successfully baked 11 out of 100 positions in one cycle.
Repeat the steps as necessary for 2-11-21 etc until you have all the positions of your character on you FG map.
The reason why I chose steps of ten for this example largely depends on the speed of your animation.
You will want the snapshot to not create interpenetrating models or even models that are too close because then FG would not catch bounce light and the character would still be dark for certain frames. This means if you’re animating the Flash go ahead and set your snapshot to single frames, but if your shot is a character monologue a bigger distance in key frames might be required.