We have modified the public license ray-tracer Mirage, written by Chris Butcher to produce motion fields and depth maps. Some images taken from sequences generated using this technique are shown below.
 

If you would like to generate ground-truth optical flow or depth maps for your own scenes, you will need to download Mirage and the motion field/depth map generator add-on. Mirage is a very powerful and flexible ray-tracer, designed primarily for research - not necessarily ease of use. There is no user interface, instead, you have to construct scenes by writing C++ routines which are then linked to the Mirage library. Click here for an online tutorial which describes how to use Mirage. There is also some sample code which we have used to generate some of our test sequences here. This is unsupported code, but you might find it useful. If you don't want to create your own scenes you can download our sequences. The ground truth optical flow files are stored in PCM (portable complex map) format. Click here for a description and some C code for reading it.