The hit function in PhysCutsCallback has a user parameter. However it is always NULL. What controls the user parameter? For example, I want to know which actor made the cuts() call that triggered the hit, so I want to set the user to the calling actor object before calling the cuts functions.

I've tried setting user() and obj() on the calling actor, but user in hit() is still NULL.

user in the callback is the Actor.user() of the actor that the hit was encountered with

You can store custom params in the extended class of PhysCutsCallback object

Ok, makes sense. I thought to store custom parameters in the extended class, but just wanted to check first.