This Toy is designed to have a print in place chassis and a separate body, which are held together with hook. Once the hook snaps in, there is no way to disassemble the toy. It also withstands harsh treatment as shown in the video. This makes it suitable for baby's and kids. The chassis is the same for every car. You can find other bodies on my Thangs page.
I recommend to print the body and chassis with support material. There are two different chassis. One is to print up side down, the other to print up side up. I recommend the up side down. The axles move smoother that way. I recommend to print the body up side up. That way the surface finish is nicer. Depending of your printer and the settings you may need a hook with different length. I would recommend to first print all 3 lenghts and first try out the shortest. In that way you can use the shortest hook possible. Remember once the hook snaps in, there is no way to disassemble it.
After printing, remove the support material and break the axles free by hand or with a 4mm hex key. After this I would recommend to drive the chassis up and down on a carpet. This smooths the axes. To finish you can assemble the hook and slide in the body from the front until it snaps in.
My models are printed with PLA on a Prusa i3 MKS+ with default settings and support material. However I took away the support material where the hook is mounted in the chassis and body.
Assembling Video: https://www.youtube.com/watch?v=zAROG4V9dmM
If you have any questions, feel free to contact me.