Hi @GitHubDragonFly …
Yo have done s[1].add(s[2]); … then threre will only be a flow… no more s[2]!
My need is to log the position of flow, to use this position to make other things.
For example synchronization of other meshes, appearence of tags, touching the flow with another mesh… etc.
The post was started to call for help for correct the movement of the chain with respect to the gears here…
Anyway, Thank You very much for Your attention. 