Spring Constraint questions

[lemond]

When trying to connect two objects, can I attach a spring to the Rigid Object's verts, not center of mass ?

Can I create a spring without a pivot?

[johner]

When trying to connect two objects, can I attach a spring to the Rigid Object's verts, not center of mass ?

Can I create a spring without a pivot?

Howdy,

You can, although you'll want to use the SBD Spring Constraint rather than the RBD Spring Constraint. The SBD Spring constraint is designed to set up constraints at point locations (a bunch of guide hairs attached to a character, for example). But you can use it for RBD Objects as well, just enter the point numbers in the "Constrained Points" and "Goal Points" parameters. See the attached file, and the examples for the node, as well as for the SBD Pin Constraint node, which has the same workflow but creates a hard constraint rather than spring.

It's probably worth looking at how those constraints are set up under the hood by looking inside the various Constraint digital assets - it's a really flexible system. If you don't need point groups for example, there's a node called "Anchor: Object Point Number Position" under the "Constraint Tools" tab that would let you roll your own point id constraint.

Good luck

spring_at_points.hip

Edited April 14, 2010 by johner

[lemond]

Thanks!

[johner]

Thanks!

You might be interested in the examples I put here on the SideFX forum. It creates a large number of spring constraints procedurally.

Edited April 19, 2010 by johner