This problem is probably because of a bad object in your model or a model that is too large for the computer memory.
-- The bad object must be removed - it will have errors or bad parameters.
The best way to locate the bad object is to make renderings with different layers turned off until finding the layer with the bad object.
Change the bad object.
-- Some models with too many polygons cannot be rendered. Especially Spanish tile roofs or lots of spheres.
Reduce the number of parts in the model and experiment to see if the rendering works.
Dwight Atkinson
