"instead of using a spring to represent the rubber could you vary the radius of the collision entity using spring math?"
As you said, if you alter the collision radius of an object in Blitz, it's very likely that the collision code will mess up and the object will pass through the ground without registering a collision.
"this way, even if it does try and go shooting off, it will radically slow down."
Another thing one could do is cap the velocity of any verlet at some max value that's beyond what any object would be expected to travel at. Would have to be a constant you could change though cause everyone uses different units of speed.
As you said, if you alter the collision radius of an object in Blitz, it's very likely that the collision code will mess up and the object will pass through the ground without registering a collision.
"this way, even if it does try and go shooting off, it will radically slow down."
Another thing one could do is cap the velocity of any verlet at some max value that's beyond what any object would be expected to travel at. Would have to be a constant you could change though cause everyone uses different units of speed.