I needed a design for a tracked vehicle for an educational robotics project. I looked around and couldn't find anything that suited. So I made one.
To make the parts, you'll need a 3D Printer, some slicer software, openscad and the specifications of the motors (dimensions, mount offset, etc.) you want to use. If you're not using the same motors I did, you'll need to modify the motor mounts.
To put the parts together you'll need various screws and nuts. I used stainless steel M25 screws and stainless lock nuts. Fixing the track segements together with rivets may also work well.
To use the parts, you'll need a power source (I used a drill battery), some motors (and something to drive them with). I used the EMG30 motors and MD25 motor driver from robot-electronics.co.uk.
You'll also need some kind of controller. I've used both Raspberry Pis and Arduinos with good success.