Calculate RBD from animated object?

[Scanner]

How do you animate an object and then have 'attached' objects calculate rigid body dynamics from the updated position?

In the attached GIF, the three lower links have calculated RBD (forceY = -1) from the REST position (shown by the dotted line) instead of the new position of the top link (... on the other side of the circle path).

I've tried animating the top link before applying RBD; choosing 'geometry changes with time' etc.

Please advise

[anakin78z]

The top piece has to be a rigid body as well, but set Active Rigid Body (under the Physical tab on object level) to 0 for that object, so that you can still animate it.

Hope that works.

-Jens

[Scanner]

thanks Jens. problem solved.

Is there any way to generate a few dozen of these chains, locking each 'top link' to a point on a chandelier? In sops, I'd start with a copy sop and a grid... but these chains have to bounce off each other and I'm being warned to animate at object level.

If there's a tutorial ANYWHERE for making something like this chandelier or wind-chime in version 5.5 (... where you keyframe a 'roof' and get the stalactites to do the dynamics), please let me know.

thanks again, Jens.

[anakin78z]

hmn..... well, depends.... in your picture, all the pieces were the same. if that's so, you can build your rbd net in pops, and use instancing. Basicly you'll pull in a point for every link, and then instance the link geometry onto it, at which point you can use them as rbds... something like that anyway... maybe that'll work for you. you'd have to animate the points on sop level, I think, then pull the animation into pops via expression, or maybe the 'points animate over time' thingamajig will do the job. No time to try it now, sorry

-Jens