Building 3D with Ikea 12 years ago
Hey - 3d artist here. When you're working with CAD/Solidworks drawings, you can import them directly into 3ds max as paths (2d shapes), and work with them in the viewport with accurate dimensions. I would be very surprised if that wasn't the typical Ikea workflow.
Failing that, I've heard of some artists actually whipping out calipers to take measurements from real-world pieces, but it seems like that method would defeat the purpose in this case.