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Help with Constraints


DeeLan

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Hey guys,

I have two quick questions. I'm trying to learn how to make constraint networks by hand. I've noticed that for some reason, when I define the strength of my constraint in sops using a wrangle sop, I only need relatively low values. However, if I delete strength attribute from my wrangle sop and control the strength in dops using the 'Glue Constraint Relationship" dop, the values needed to achieve the same effect suddenly become massive. For example, when I define the strength in sops, I only need a value of 10 to get the effect I want. However, controlling the strength in dops (no strength attribute defined in sops) require a strength of 100,000 to achieve the same outcome. I'm wondering why there is this massive difference between sops and dops.

Also, say I wanted to add a second fracture object to the sim (unique the first one), with a constraint network of its own, whats the best way to go about bringing the second constraint network. From my understanding, adding a new object is as simple as adding a second RBD Packed Object dop, merging that with the original, and plugging the merge into the rbd solver. But with constraints it seems I would need a new constraint network dop and a new glue constraint relationship dop for every set of constraints. I'm just wondering if there a way to do it all through one constraint network dop and use multiple glue constraint relationship dops, similar to plugging multiple RBD objects into one RBD solver.

 

constraints.hipnc

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The strength you put in as a point attribute multiplies with the strength set in SOPS. So a point attribute strength of 10 will be a huge number if its set to 100,000 in DOPS. I always set my DOP strength to 1 so I dont have to think about this. Not sure why it works like this, but it sure is easy to trip up on!

You can combine constraints together into one constraint network. Just use a merge node to pull them together. They need their own Data name to tell each other apart. I've attached a really simple example. I do it with springs, but you could use glue constraints instead.

Hope this helps!

constraint_networks.hip

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