Assuming the VRay renderer is GPU based, you'll need a compatible video card with VRAM suitable for the scene you are attempting to render. You can improve performance almost linearly with multiple parallel cards *but* you'll never get a 3 hour => 3 minute reduction on a desktop. Even a render farm might not get that kind of performance increase. And, of course, hardware is only part of the equation - properly optimized scenes are also necessary for faster renders.
Anything that can handle high-end rendering will handle 2D AutoCAD, so I recommend you take this to a VRay forum for more complete answers.
If you are going to fly by the seat of your pants, expect friction burns.
"I don't know" is the beginning of knowledge, not the end.
Following up on your thread, were you able to find a solution or a workaround?
Did any of the posts in the thread help with you issue?
Please use the Accept as Solution for those post’s that helped. It may benefit other users who might have a similar question or issue.
Thanks for your time.
Sarah Emmsley
Technical Support Specialist