In certain cases tennis players want to customize the grip of their raquet. Some want a size between the standard ones, some want to adjust proportions between the wide and narrow sides, some want to replace pallets with a molded grip. This all can be done by molding urethane foam into the desired shape, which is pretty much the same as the stock grips are manufactured.
This is a mold model which can be customized and 3D printed. The model is made with OpenSCAD, which means that the shape customization is as easy as adjusting the dimensions in the source text file. FDM printing from PLA is fine for the mold, and any printer which has large enough buildspace should work.
The current model is 4 3/8 (#3) grip for Wilson Ultra 100 v1 model. The raquet model is important because different raquets have different shape of the throat (which enters the grip), and the mold needs to be adjusted to ensure good contact with the throat (which, again, comes down to adjusting the throat dimensions and rounding radiuses).
The repository also includes the spacer which is used to center the hairpin in the mold.
And here are few pictures illustrating the the molding process:
