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Inequality Constraint in PBD
Posted: Sat Sep 20, 2014 11:46 pm
by apapaxionga
In position based dynamic, equality constraint such as distant constraint can be solved using constraint projection method. However, in paper related to PBD, how to solve inequality constraint are not mentioned a lot. How to solve the inequality constraint in the PBD framework ?
Re: Inequality Constraint in PBD
Posted: Mon Sep 22, 2014 5:21 pm
by Dirk Gregorius
You simply skip over the constraint if the inequality is satisfied.
Re: Inequality Constraint in PBD
Posted: Mon Sep 22, 2014 10:04 pm
by apapaxionga
Dirk Gregorius wrote:You simply skip over the constraint if the inequality is satisfied.
Then, if the inequality constraint is not satisfied, how to solve the constraint?
Re: Inequality Constraint in PBD
Posted: Mon Sep 22, 2014 10:57 pm
by Dirk Gregorius
Conceptually very much like equality constraints. It depends on the type
Re: Inequality Constraint in PBD
Posted: Thu Sep 25, 2014 8:35 am
by raigan2
If your state is within the valid region: the constraint isn't violated, you don't have to do anything.
If your state is outside the valid region: find the point on the surface of the valid region closest to the current state, this is your target state.
So, for a min/max distance constraint:
if(current_distance < min_distance): project to min
if(current_distance > max_distance): project to max
else: do nothing
("project to X" means "solve distance constraint using X as the desired/target/rest distance")