Hello,
I was wondering if we were specifically limited to Additive Manufacturing Processes for the CAD Challenge’s Extra Prize, or if we could use Subtractive Processes such as CNC Milling or Plasma Cutting.
Hi Harrison, apologies for the late reply, but I am new to the VEX Forums as of earlier today. 
This is a great question! The challenge specifically focuses on 3D printing, so that’s an affirmative to the additive mfg process. If you do not have access to a 3D printer, you may send your file to Shapeways or Sculpteo, or identify another local source that can provide this service, generally for a small fee.
And if you need a 3D printer, I certainly wish you luck in the Design part of this challenge so that you may win one!