My niece has Special Needs and sucks/bits her thumb. This guard tries to prevent some wear and tear on her thumb. I used 95A NinjaTec Cheetah TPU to print. I used support and a raft only for the first few layers(to support the bottom curve along the wrist-end). There are commercial products but they are expensive and don't fit well.
I scanned her hand and forearm in with my iPhone using an app called EM3D. Proper light is key to a good scan. 4000K, 95CLI, worked for me. Positioning her on a table laying flat, with her arm hanging down over the side was the easiest way to keep things steady. I rotated around her arm.
Once I got a good scan, I tried many different CAD/Software packages. Blender proved to be the most capable for the amount of verts. After working with the hand model, and learning Blender, I was able to come up with what you see here.
The Voronoi pattern used allows for structure, breathability, and a little bit of stretch so the fit around the widest part of her hand can be accommodated without it being too loose.
The author marked this model as their own original creation.