I have a joint on a motion path for some ooze drips, that the motion path deforms. I'd like the drips to always aim down regardless of where the drip is on the path, or how the path is rotated, etc. The drip is just on a single joint.
I tried something where a locator was placed just below the joint and the locator was point constrained to the group following the motion path, then the joint was aimed at the locator, but when the rig rotated and translated, the locators weren't lining up properly, and some weren't following properly, which I think was from an unforeseen dependency loop.
The only other things I can really think of are IK handles, add an extra joint, but then I still don't know how to get it to aim down, as the rig twists and rotates and moves, and I could use a hair curve, but that really seems like over kill for what I want to do.
The best thing would be would just have something that always has it point straight down in z, or -z for the other side of the rig, but I'm unfamiliar with any kind of constraint or expression like that.