advanced rendering for AutoCAD
I don't know for sure, but I'm guessing you're also having a precision problem related to either the drawing units or the model being located far from the origin. See the discussion below:
Check your units first-- using _DDUNITS and make sure they agree with the scale of your model. After that check the coordinates to make sure the model is not located too far from the origin.
You can also run into problems if you're using a very long lens and the camera is located far from the model.