All vector content, extruded text and a simple ground plain to catch shadows, 50% reflective.
The custom view shows all shadows & reflections correctly, but the camera will not show them.
I've deleted / re-created cameras, lights, floor plains AND objects without solving the issue - it's the first time it's occurred in many similar projects.
Win7 x64, 32Gb RAM (plenty), nVidia K5000 with 4GB handling previews & rendering. The problem persists even if switching to CPU rendering (which takes ages, obviously) so the driver is not to blame.
If you start a new project, create a floor, add a 3D text layer, add a camera using one of the presets say 50mm lens, add a light and set up your extrusion and add shadows does it work? If not then reboot. If you can solve the problem with a new project then import your project that does not work and see if that works by copying and pasting layers one at a time into the comp that works to figure out where the differences lie. If that doesn't work try posting the project so we can take a look at it.
Thanks for your suggestions Rick. I was in the process of re-creating a new comp copy/paste layer by layer and suddenly found it to be working properly in the original comp! I'm at a loss to explain this one, but can't now replicate the issue. Best guess, switching to CPU then back to GPU rendering with reboots inbetween has re-set something in this particular project file.