New Physics Class: RigidConstraint

[rotbotrotbot (Burgerio)]

How is this different than a weld constraint?

[LeanderDevForum]

That’s really cool i will use it

It’s cool that Roblox have so many features

[Lorourkethebest]

I’m still unsure how to attach stuff to avatars without scripting. But I did record myself attaching free models to each other because I have nothing else to do lol. I can’t link the video but it was an amazing video I just recorded. On a serious note, thank you Roblox, I need this update for building!

[BlueyHeeler96 (Bluey Heeler)]

I’m hyped up for the ability to use these for destruction in the future. I’ve been trying to roll my own destruction physics script, but I must be getting the math wrong or something because cars will just instantly fall apart the moment I try to drive them. Hopefully this will fix that.

[WingItMan]

It would be pretty great if Roblox’s devs came out with a “soft body constraint”

[LeanderDevForum]

yeah ok you are a scripter lol ok cool XD

[ValiantWind (Val)]

I mean, you can see my display name right?

[AgedGraves]

The future plan of this sounds super useful! It will make time in the studio much more efficient and clean!

[Fm_Trick (Trick)]

Using a RigidConstraint, when I attach a BasePart via Attachment to a skinned mesh via Bone, both of which the client is the network owner of, replication breaks on the skinned mesh side of things… is this intended or should it be considered a bug?

[Experties (exp)]

I love this update! I used to be stuck using AlignPosition to kind of simulate a “weld” between two attachments.

[GMaxZet]

Thank you. Really nice addition.

It would be great to have some “soft” weld constrain, where the other connected part will not join the assembly. To have two assemblies welded together is currently only possible by using, e.g. Hinge constrain. Or by copying CFrame, but that causes visual glitches.

[qwertyexpert]

@subcritical

We plan to add opt-in automatic destruction. This means the RigidConstraint dynamically breaks based on force limits that you configure if you so choose. The timeline for constraint destruction is not set in stone yet, but consider this a peek into what’s next.

YES! Finally! Not only do we have a new rigid constraint that makes sense (goodbye Weld.C0/C1), but they will be force-breakable too!

@GMaxZet

It would be great to have some “soft” weld constrain, where the other connected part will not join the assembly. To have two assemblies welded together is currently only possible by using, e.g. Hinge constrain. Or by copying CFrame, but that causes visual glitches.

You can do this using AlignPosition/AlignOrientation with RigidityEnabled set to true

[Lucas_YT111 (Hakr)]

This will be really useful for cars crashing when the force damage comes out

[Fm_Trick (Trick)]

Using this new constraint breaks down skinned mesh rendering - see my bug report here:

Skinned Animations Rendering Issue

EDIT: I’ve narrowed this down to the use of the new RigidConstraint. Removing all RigidConstraints from the humanoid model solves the problem for me. Reproduction Steps Have multiple skinned rigs within your camera’s view Play any animation on them Move the entire rig back and forth edit: rig must have RigidConstraint being used in it. Repro file has been added privately. Expected Behavior I expect the animation to play without degraded performance, and especially stay rigidly aligned t…

[SpanishFriedEggs (Eggs)]

Is there a way when making the constraint break on force to show how much force is being applied to the constraint?

[BuilderBob25620 (BuilderBob)]

Hey! That’s a really good idea! I assume that there will be an event or something. Perhaps this information will be passed to any connected events?

[BuilderBob25620 (BuilderBob)]

@qwertyexpert

goodbye Weld.C0 / C1

I don’t quite agree with this. For me the JointInstance | Roblox Creator Documentation and JointInstance | Roblox Creator Documentation properties of the weld are really useful, as I can move entire welded assemblies just be editing the joint offset on a single weld.

I understand that the WeldConstraint | Roblox Creator Documentation was meant to replace the Weld | Roblox Creator Documentation, and I do use it. However, whenever there’s an instance when I need to move a connected instance and all the parts connected to it, it’s easier to use the C1 property of a weld. This isn’t to say that the weld constraint is useless or inferior by comparison. Quite the opposite in fact! However, the C1 provides information about the joint offset automatically so I don’t have to calculate it manually.

While this is quite the long tirade, my point is that I wish that the WeldConstraint had these properties or some implementation of them. It’s already using some offset internally, so why don’t we have access to it? It would be a lot easier if we did.

[qwertyexpert]

@BuilderBob25620

I understand that the WeldConstraint was meant to replace the Weld, and I do use it.

I hate WeldConstraint with a passion. It has some weird inscrutible internal state that gets corrupted randomly and misaligns parts for no reason. There are horror stories of entire builds being lost because I connected things with WeldConstraint in Studio. I tried to move the build and everything got misaligned by the WeldConstraints, even though the game wasn’t running. Then, because they kept their weird internal state, even after I pressed undo, they continued to corrupt the build every single time I tried to do ANYTHING to it.

I don’t remember if I was ever able to recover it.

[BuilderBob25620 (BuilderBob)]

Wow, this has never happened to be, but I can confirm that I would be very irked to have something like this happen.

How long ago was this? Has anything like this happened recently? If so, then I hope that the RigidConstraint won’t use a similar internal state. Otherwise this very same thing could happen as well.

[GolgiToad]

Instant fan! Threw a non-skinned accessory on my skinned mesh and added a RigidConstraint, and boom!