Made this from scratch in TinkerCad to be added to our table top RC Crawler course for the 1:24 scale crawlers we have. It's pretty simple as far as mechanics, I made the ramps two piece so you could place them on a bed easier if you have a smaller print bed. The other reason was since you'd be using M8 screws it adds extra counter balance weight to bring it back down to one side, I added multiple nuts to it to add extra weight and works perfectly.
I added diamond plate pattern to give extra texture for traction. You don't need the caps for the base to hold the ramps down, but doesn't hurt.
I super glued the approach ramps to it, but I guess you don't need them but makes it longer, but with added weight of bolt and nuts it will still come back down to one side even without the approach and departure ramps if you didn't want them.
UPDATE: VERSION 2
Base: The original dimensions were found on the manufactures website but unfortunately there weren't very clear on inner dimensions of inside tire to inside tire so the ramp was a little too wide and the diamond print on the top did not have enough grip for some of the tires on the 24th scale crawlers we had. Due to this I made the position of the base towers that the ramps sit in a little more close together, made them skinnier and shaved some uneeded material off of the base as well.
Base Caps: shaved the top to prevent any possible rubbing from inner tire and didn't need to be rounded on the top anyways.
Departure/Approach Ramps: no longer separate, instead integrated into the main ramps. Made them solid to make printing easier.
Main Ramps: Redesigned the ramps to be mirrored diagonal slots that come to a point that should have better grip VS the diamond plate pattern on original that was just too small at this scale to do anything for grip, especially the stock tires that come on the SCX24, if you have the proline tires they have way better grip and compound and would do fine regardless.
The original ramp seemed to fit a 1:18 scale car for the most part, otherwise I'd go with version 2 for 1:24 scale crawlers.