Been working on an implementation of a fast algorithm for finding the closest point on a triangular mesh using a spatial aceleration structure for the broad-phase, and wrote an interactive application showing it in action using my SlimEngine++ software 3D rendering framework:

https://youtu.be/B0rwUXFKca4
https://youtu.be/vaFkAab-nYg
https://youtu.be/8kabp2JLkuw

The CPU implementation is still fast enough for realtime on a 50K poly mesh, even without being multithreaded or vectorized. But it can also optionally run on the GPU using CUDA.