This is an extra flourish added to the tank to improve its visual impact! This does not have a specific mechanical function, but it makes the tank look awesome:
The large, spiked roller on the front of the tank adds to its menacing appearance. Earlier in the chapter, we discussed how the roller is set up with a pulley and a rubber band that are attached to one of the drive motors, which makes the roller spin when the tank drives.
The roller is a custom 3D-printed part. You can download the file for the roller where you downloaded the LDD for the tank earlier:
If you do not have the means necessary to 3D print this component, ...
