Model touch, friction, and soft contact in simulation

What the people stuck here are trying to get done

When simulation is the core place I train artificial intelligence (AI) and test control, I want it to model touch, friction, stepping and soft interaction, so what I train in simulation transfers to the real robot.

Who needs it solved

Robotics founders and researchers who train control and AI in simulation and then can't transfer it to hardware.

What makes it hard

Sim results don't survive contact with reality, forcing expensive hardware-in-the-loop workarounds ("the robot pokes a chunk of skin or a cadaver").