Help with Breaking Constraints Based on RBD Y Position

[Masoud]

Hi everyone,

In a rigid-body simulation, I'd like to break constraints if the RBDs go above 1.5 in the Y position (i.e., @P.y > 1.5).

I've added a SOP Solver to the last input of the Constraint Network DOP, but I'm not sure how to access the Y position of the RBDs inside the solver.

Any ideas on how to reference the RBD positions correctly?

 

Thanks in advance for your help!

[fencer]

Try to search first, there are many examples how to work with VEX and constraint on odforce or google. 

https://www.sidefx.com/forum/topic/78398/

https://www.tokeru.com/cgwiki/HoudiniVex1.html

https://www.tokeru.com/cgwiki/HoudiniDops.html#constraint_networks

[Masoud]

Thank you

[hannes603]

if(distance>chf('slider')  ) 
{
setprimattrib(0, "constraint_name", prim[0], "", "set");
}
 

that usually does it for me 

[Masoud]

Thank you Hannes

[paranoidx]

inside SOP Solver you can apply 1 in 2 options:

1. Merge the dop_geometry data into second input for Y position per step of the RBDs (select by name or DOP id to select the animated geo)

2. If the animated RBD geometry ahead at SOP. Use a merge node, merge the animated geo into the SOP Solver

Both give you animated Y position of the animated geometry. Input that to 2nd input of the VEX wrangle to apply operation on primitive. 

Edited June 7, 2025 by paranoidx
clarify answer