Wire Groups from sops?

[Macha]

I have a ball of n curves imported as wires into a dopnetwork.

All wires have one start point pinned to a constraint. I would like bunches of m (m<n) wires, each bunch affected by a different force, preferably radial. Kind of like an exploding spiderweb effect.

What is the best way to group the wires bunches? I thought about sop groups, but they are not accessible in dop wires (?)

Or even better, what is the most procedural way of doing this? (would the Apply Relationship dop be useful here?)

[Macha]

To be more specific, this is one idea:

For each bundle of wires I group the start points of those wires and hard constrain them to a center point. Then I take the end points of those wires and use a spring constraint to another, animated, constraint.

It is like wheel. The bundles of wires being spokes (one spoke = one of the bundles of wires). The hub being the hard center constraint, and the wheel itself being the spring constraints.

I think that should be doable?

Edited January 26, 2011 by Macha

[anim]

I'm not in front of houdini right now, but you can make your force in SOP solver

if you attach groups or make some bundle_id attribute for your wire bundles in SOPs

then in SOP Solver use that info for generating vector attribute of wanted direction and speed for each bundle (based on that bundle_id attribute)

name that vector attribute "fexternal" and it should be automatically used by wire solver as external force for each point of wire

as for constraints, it should be also possible if ou generate some info in SOPs of which points to which position should be constrained (per timestep so it can be animated) and use that info in Apply Relationship and SBD Spring constraint

[Macha]

Thanks, I didn't know about fexternal. I'll give that a go. It sounds very useful and I may be able to avoid the relationship dop

[Macha]

I made a little test but I am puzzled as to why it doesn't work.

When I create the attribute in sops it works, but when I do the same in a sopsolver the fexternal force shows up (see vector) but does not have an effect. Any idea why? Anything to do with naming perhaps?

wires.hipnc

Edited January 26, 2011 by Macha

[anim]

you can animate that attribute in SOPs if it's enough

but to get this working in DOPs you need to modify RestGeometry by SOP Solver

(kind of strange that modifying Geometry doesn't work, I thought that turning off Deforming Geometry checkbox should work)

wires_fix.hipnc

[Macha]

Thanks Thomas. I eventually found a pure sop method to set forces and groups procedurally, in a simple network. It's an amusing effect. If I do something interesting I'll post something.

Edited January 27, 2011 by Macha

[smaugthewyrm]

I eventually found a pure sop method to set forces and groups procedurally.

i'd love to see a hip file. this sounds interesting. i've just been playing with wires lately.

[sabotage]

Hello guys I was wondering if I can add forces with vopsop in the wiresolver is it possible thank you.