Using the demo of IR 3.2.9 and Cindigo 3.2.9.1.
I have a GTX280 in a Windows 7 SP1 box, and when I render the Cindigo tutorial project with GPU acceleration selected, the 3 spheres in the scene disappear. They render as expected when GPU acceleration is turned off. This happens both in the standalone renderer after .igs export, and in the integrated renderer.
I have the latest 296.10 drivers.
NB: I have a new 2 GB GTX 560 on the way, so if this is a problem due to the older card, then it won't be a problem for me much longer.
Jeff

