Ok, so I’ve got a model which contains as a component a mechanical arm onboard a vehicle. And I need to animate this arm picking things up from one spot on the vehicle and transferring them to elsewhere on the vehicle, while the vehicle is moving through its surroundings. The arm has to move to grab an object, grab with a gripper, then move the object with the arm, then place the object down, open the gripper and let the object go, before moving the arm again while the object stays in it’s new location.
This would look like a job for parenting done via the “child of” constraint, with the constraint being applied to the objects being moved and the arm set as parent, then the strength slider at the bottom of the constraintrising over the course of one frame from 0 to 1 during pickup then dropping back to 0 once the object is put down.
BUT this doesn’t work well when the vehicle body, a parent of the arm’s baseplate object, is moving around, translation and rotation. Rather the object with the constraint start drifting around strangely, something related to the which frame the origins are being constrained in. And often an object doesn’t properly maintain it’s transform (the way you can ctrl+p Parent (keep transform) and also keep transform when unparenting, with permanent parents rather than constraints) when going from a 0 influence to the full 1 influence of the constraint, this would seem to only be workable if the origin was at global 0,0,0 before and after the influence changes.
Has anyone got suggestions of how to handle this, or how to achieve the same sort of effect without this constraint, maybe with another constraint which doesn’t have problems with being done in the moving reference frame onboard the vehicle.