How do the new physics constraints work?

The documentation for them on the DevHub is less than helpful. I’m particularly interested in AlignPosition and AlignOrientation. They seem to be far more difficult and confusing to implement than the old BodyMovers, but because Roblox is no longer actively supporting them I think it would be good to migrate everything over to the new system. Any help on this would be greatly appreciated. Thanks!

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You may look into this archived paged of wiki.

AlignPosition moves 2 attachments so they have the same position.
AlignRotation rotates 2 attachments so they have the same rotation.

Thanks for the quick explanation on the two. I guess my question now is if there is any equivalent to BodyPosition/BodyGyro in the new physics system, or some way to emulate it without the need for 2 parts. Something where you just enter in the position you want the part at and it will try to stay there. I really don’t see the benefit to requiring 2 parts for all these movers.

I think that’s a VectorForce. You can set it relative to the world instead of attachments(?) to make it work without needing two parts.

VectorForce seems to be the equivalent of BodyForce, not BodyPosition.


Could we get an idea of what you are attempting to achieve? You may not even be looking for AlignPosition or AlignOrientation, depending on what it is that you are trying to do. Either way, having a use case would better help to solve the situation you’re facing.

On a side note, perhaps the official post regarding the change from legacy body movers to the constraints could help you out with explanations.

I’m merely trying to convert all the old BodyMovers in my game to the new ones without having to add a ton of new things or change how they currently work.

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I think the matter of converting them over is working with attachments and the new BodyMovers themselves. They still work relatively the same (don’t quote me on that). Which BodyMover objects are you presently using and what are they for?

I’m currently using BodyPosition, BodyGyro, and BodyVelocity for ship movement/rotation in my space game.

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Ok yeah. So AlignPosition, AlignOrientation and VectorForce. The most I know is that these will require attachments somewhere to help determine the axis that they work from. I’ve got no other adequate information as I myself personally have been experimenting with these constraints (previously with legacy BodyMovers) for quite a bit of time now. Haven’t had any real use for them.

Alright, I guess I’ll have to experiment a bit.

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