Ok, I’ve found a slightly better… but still hacky approach. I think it’s better than ‘CalcVelocity’ because smoothing the friction isn’t needed.
There is still a little slippage but it is about 20 times better. I’m using ‘AddImpulse’ instead of ‘AddForce’ because ticking the red box allows me to change the velocity directly (so mass is irrelevant).
