In vellum simulation, how can I break glued points, over time?

[Masoud]

Hello;

In a simple vellum sim, I would like to break glue constraint between two animated objects, so in DOP, I add a "SOP Solver" to modify "breakthresholdscale" attribute over time, but it doesn't work.

How can I break glued points, over time?

 

 

Thanks for helping.

Glue_01.hip

[anim]

It's not updating since that vellumconstraints1 node is executing only on creation frame so it will scale your breakthreshold by attribute only once

you can for example change your sopsolver1 to operate on ConstraintGeometry and modify f@breakthreshold of glue constraints directly

Glue_01_fix.hip

[Masoud]

Hi "Tomas"

Thank you for helping. It works fine, but:

1) Is there any other way to fix it ( Actually I can't understand how it works )?

2) How did you find out what you should put in the "Data Name" tab is " ConstraintGeometry " ?..!   I mean how a user like me can come up with such a solution?! 

[anim]

1. obviously there is infinite number of ways

here is for example way using Vellum Constraint Properties DOP, using the attribute from your sopsolver1 to update breakthresholdattribute on constraints, 2 ways:

Glue_01_fix_alt.hip

more proper one by considering values of both anchors and consider smaller one for breaking (or avg or whatever):

int pts[] = primpoints(0, @primnum);
float bts0 = point(1, "breakthresholdscale", pts[0]);
float bts1 = point(1, "breakthresholdscale", pts[1]);
float bts = min(bts0, bts1);
breakthreshold *= bts;

or simple where you get just the first, whoch in your case will still be ok:

float bts = point(1, "breakthresholdscale", @ptnum);
breakthreshold *= bts;

 

2. well, constraint primitives are stored as "ConstraintGeometry" data and for example Vellum Constraint Properties node works on that data too, so it's a good thing to know when you want to modify constraints compared to "Geometry" which contains the actual geo 

Edited April 10, 2020 by anim

[Masoud]

Thank you "Tomas"