Quick measuring for the dunes
I'm sure many folks are modding away on various entries for GTR. Here is a quick method I use in the shop just to check things on the fly. A piece of 1/8 in plexiglass is just over 3mm. A standard weight playing card (not some odd ball collector card) is about 0.28mm. Now its important to say that I verified (double checked) these with my digital micrometer. So now I know that the plastic piece and 2 cards together is a bit over 3.5mm. Add or subtract playing cards as needed. I also place the vehicle on a flat clean pedestal to make a measurement.
I used this card trick when I was building guitars to check string height. As I recall at the 12th fret on an acoustic you should have 6 to 8 playing cards and on an electric 4 to 6 playing cards. I think those are right but I've not built one since the pandemic.

Discussion
Hey guys! Many ways to do it.
Good stuff. I guess some are wondering how to measure that clearance gap fairly accurately. Yep one has to use a smooth flat surface. For me, simple, my "guages for measuring are the shanks of the various size drill bits. Ha! if you know the size of your drill bit, you are set!
Cheers good luck out there all!
- Nice idea with drill bits - for me I want to be able to sweep the area under the vehicle from front to back. — AbbyNormal
- If you press your car down into a ball of clay, you can then measure the squished ball using your calipers... — Stoopid_Fish_Racing

nice tip!
I have brass scrap of dif sizes, and use it for Mt car clearances
helps to have a set of calipers! everyone should get a set,
and from working in the lab, harbor dial mics are as good as the big guys
the digital ones can have issues, though (cleanliness messes with them)
dr