CFrame and Constraint Issues

General rundown of the operation:

Model has two parts, the lower crane harness and the upper spool. Each is an individual unanchored model that is welded with a part that is anchored. These models are moved using PrimaryPart CFrame.

The hook system is an unanchored part that is connected to the spool using 3 rope constraints so that it hangs freely.

When moving either the harness or the spool, I get this issue: https://gyazo.com/3ecd6f18558bb42a2bfa11d513eae500

Any idea how to resolve this?

Perhaps try moving the bottom thingy with body position

It needs to hang freely for this operation.

This seems like it might be part of the issue. https://gyazo.com/ed0af609275f3219677c93e60cd9cbbd

Why do parts do this?

That’s really weird, honestly, I’ve no clue why that happens, are you sure the part(hook) isn’t welded to anything else

Yes. Seems to be an issue of sleeping parts.

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https://www.roblox.com/games/82472241/Construction-Site
The crane I built here just uses Constraints for movement and rotation. I have the hoist on a vertical PrismaticConstraint and the trolley moves out/in with another PrismaticConstraint.
I just used SpringConstraints as the cables, with the Radius set to 0 and the Thickness set to .1 which allows the springs to look like cables no matter what the length is.
The whole thing keeps the hoist from swinging all over the place and gets rid of the sleeping issue you are seeing. It also allows the bucket to catch on items like the ground and building so it does not move with the whole crane when that happens.

Not necessarily how I would’ve liked to go about it, but this is definitely the only effective method I’ve tested so far. Thanks so much!

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