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3 Joint leg flipping problem

Is this caused by the spring solver or something else? I had the leg built a while ago and have a bunch of things added to the rig. is there a way to fix this after the rig is built?


Please any help would be appreciated.


I notice that the twist joints flip in sequence. Anyway to prevent this from happening?

It is because the reference transform for the roll is passing 90 degrees.
it is a limitation of the current design.

Probably can be greatly improved, this component is asking for a revision for a long time :sweat:

however usually the animals rear leg doesn’t fold that much.

@Miquel this rig is for a client of mine, is there anyway to disable the roll for the lower leg in the meantime so it won’t flip for them?

this is true, a horses leg does not do that but the client insists on me fixing it.

yes, I am pretty sure you can workaround it, changing some connections.
But I don’t have a recipe ready solution

@Miquel No problem, I’m trying to figure out which connections to disable to not break the way the leg behaves. I’m still pretty new to mGear’s architecture which connections would I have to work around to disable the lower legs rolling or flipping?

@dew here is a workaround. but please check carefully. Maybe breaks other stuff

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@Miquel hey I gave it a shot, it def fixes the flipping issue when the offset is made but the lower joint moves as well. I’m not sure why that is since I don’t know how the module is built.

Any suggestions would be greatly appreciated, else I’ll have to tell them that it’s a limitation with the rig component.

I would treat it the same way a human leg is, just stretch out the feet and position it to replace the 3rd joint

cus there’s a few similarity’s between horse and human skeletons

hope this helps

The rig is already built with a lot of custom components. I’m beyond the point of having the mGear guides still around. I cannot rebuild the legs again I unfortunately need a work around for my client to stop the flipping problem. Anatomically it doesn’t make sense but this is the way my client wanted me to rig it using the quadruped leg component. I didn’t catch the flipping problem until they brought it to my attention.

I’ll have to check again tomorrow why the toe joint is rotating with the flipping offset. It could be then way I parented things but I have no idea. Kicking myself for not checking things out way sooner before I built the rest of the rig components.

can you send the file? I’ll try to help out if I can

It’s difficult to since it’s an NDA client project. I could possibly remove one of the legs and just send that, though I won’t know until I’m back at my desk. However if you want to try yourself you can just build it in shifter. It’s the 3 Bone leg component. You can attach a foot to it and see it flipping when the ankle is rotated too far in places.

ah fair enough but yeah I’ll have a look.

yeah I can replicate the issue

though out of curitosity how was it setup originally when it was generated?

The body itself is all mGear but all of the extra stuff. Face rig harness ect are all built by hand. I can’t detach anything without breaking more things.

@dew can you rebuild your rig? data-centric style?

Unfortunately I’m a bit past the point of rebuilding anything. Deadline ect, all of the extra pieces i built by hand are already very integrated onto the final rig sadly.

appologies if this does not help, would it not be possible then to make a new rig for the legs and then combine it with the old one to replace it?

No worries, I unfortunately have too many things connected to them to take them apart like that.

@Miquel I tried your method again and I think it worked this time. I may have had the order incorrect.

I do have a question about this module specifically. How is it set up differently then the 2Bone Leg. I did notice the 3Bone leg does not use the mGear_IK2FK bone solver node, this is just using the mGear rollSplineKine and matrix nodes to function. Is this using traditional maya IK solvers? Just confused as to why the rollSpline is flipping at 90. I’d like to know more about how these modules are set up so I can better come up with solutions to fix them or avoid flipping like this in a custom module.

Thank you again for all of your help.

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