Thank you for unswervingI think most of the people making there own bumpers arent using CAD. Its more of design as you go type project, at least thats how I do it. Where are you located? Might be able to find someone local that has built there own that could help you out.
Hello Hot DamnAre you wanting to make this yourself our are you looking for the dimensions so you can take it to a shop and have them build it?
If your doing it yourself then I would recommend finding some designs that are out there that you like and start from there. Draw out a few ideas and then get started with cardboard. One trick I learned is to use bobby pins (like you use for sewing) to hold your pieces of cardboard together while your designing. I wasn't trying to be a dick with my first response but there aren't to many DIY home shop guys that have the computer software our the machines to use CAD. The process I mentioned is the way I make all of my stuff. I take all the little things that Ive seen and combining them into one to make something of my very own.
Heres a link to my front bumper build, hope it can help in some way.
And as you can see, Cardboard Aided Drafting works great