GCP toolkit is a set of reusable functions to integrate Geometric Contact Potential (GCP) into a simulation, built on top of the IPC toolkit. GCP has been merged into IPC toolkit and this repository is no longer being actively maintained.

Geometric Contact Potential introduces a new type of barrier-based collision model, with the following features different from IPC:

• Large $\hat{d}$ allowed: In IPC, if $\hat{d}$ is larger than any edge length, spurious contact forces would push neighboring vertices apart, which does not happen to GCP.
• Convergence under refinement: The GCP potential is derived from a continuous formulation, and the discretized potential converges to the continuous version under mesh refinement.
• No spurious forces: GCP elliminates the spurious forces of IPC in various cases (check the paper for details) by considering the local normal and tangent directions.

This is not a full simulation library. As such it does not include any physics or solvers. A full simulation implementation in PolyFEM is available here.

Geometric Contact Potential differs from IPC only in the potential formulation. It reuses existing utilities in IPC toolkit to collect collision candidates, perform narrow phase CCD, etc. Below shows a table of GCP classes with their IPC counterparts.