DOPs Two State Constraints

[Peter Quint]

This one has me beat. I'm looking for a way to simulate an object attached to say a rope - so that it initially falls freely and then becomes constrained when the rope becomes taught. So a perfect case for a two state constraint with a distance based switch between states, I thought (the spring constraint set with a rest length appears to push the object as well as pull it, which a rope would not do). But the constraint seems to stick rigidly to its first (unconstrained) state. There's probably some obvious mistake, but I'd appreciate any help.

Thanks

Petertwostate.hipnc

[anim]

in order to measure the length I think it needs to be spring constraint (even with zero strength). Then the Two State Constraint would work

look at the file

but you can encounter unstable behavior at high strength settings of the second spring

you may consider using only one spring constraint and blend in strength(maybe damping too) with expression based on distance with a little falloff to avoid unstability a bit. The distance can be obtained with dopfield() expression

twostate_fix.hipnc

[Peter Quint]

Thanks. Perfect.

in order to measure the length I think it needs to be spring constraint (even with zero strength). Then the Two State Constraint would work

look at the file

but you can encounter unstable behavior at high strength settings of the second spring

you may consider using only one spring constraint and blend in strength(maybe damping too) with expression based on distance with a little falloff to avoid unstability a bit. The distance can be obtained with dopfield() expression