If you want to build your own one-off chassis here is a nice solution:
I have some very special 3D CAD software to design frames made from tubes which connects directly to the laser cutting machine.
All connections of the tubes are calculated by the software is such a way that they fit on their exact location.
This is done by adding possition helpers (pins and holes) to the tubes which interlock.
And especially round tube is very nice, because it calculates the exact fitment of the tubes by cutting out a fish mouth.
It looks like this:
Faroux_3D_Design_1.jpg
The software and laser tube cutting machine can handle round, rectangular and square tubes from 20mm to 220mm.
Also it is possible to laser cut the needed aluminium panels like floors, side panels directly from the software.
Of course already existing CAD drawings (STEP files) can be imported.
I was wondering if offering such a service to kit car builders would be a success.
It definitely makes building your own designed chassis very easy.
You would get a flat pack with all tubes in the correct size and they all fit!
No cutting and grinding would be needed only welding.
These are 2 pictures of a Le Mans winning Group C racer:
Faroux_GroupC_racer.jpg
Detail_roundTube_chassis.jpg