The feature, motivation and pitch

I am working on a problem where I need to differentiably calculate the distance between two convex objects, including when they are not colliding. For many of the collision algorithms, the distance is hard-set to 1 when there is no contact, breaking the gradient chain, and the function mj_geomDistance does not appear to exist in MJX (unless I am missing something).

Either porting mj_geomDistance, or setting a flag that lets the collision algorithm leave the positive distance in place rather than hard-setting it to 1, would be appreciated.

Alternatives

Currently, since one of the objects is a sphere, I manually edit

I have no idea how this might break the simulation (other collision algorithms currently set distance to 1 whenever there is no contact). It has not caused me trouble so far.

Note I also need the "contact" normal, but the frame is set appropriately even when there is positive signed distance.

Additional context

No response