Keeping rotation limits for Rigify rig?

[Mickey Ho]

Neither the FK or IK bones in the Rigify rig have rotation limits. Is it possible to carry them over from the original Daz rig?

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Another question, how to disable IK stretch in the Simple Rig?

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Using Blender 4.1, and Daz Importer 1.7.4.2082

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[Alessandro Padovani]

Looking at #2024, it seems rigify works better with its own limits, that we should not modify.

As for IK stretch in Simple IK, one way is to copy location and rotation of the IK targets in FK hand/foot, then keyframe the influence as desired. But this should be done by Thomas to update the control panel, eventually.

• ik stretch on/off: influence 1/0 for location
• ik on/off: influence 1/0 for location and rotation

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[Mickey Ho]

Thank you. Well, I think the foot roll bone in Rigify is a special case, but it is part of the IK bones. The rotation limits of FK and IK are independent, and the rotation limits of the Daz rig is for FK bones, so I don’t think it will mess with the IK bones. The bug with the foot roll bone comes from disabling all the rotation limits. From my experience, adding rotation limits to the FK bones in the Rigify rig doesn’t cause any problems. It’s just very tedious to do it by hand.

[Alessandro Padovani]

You forget there’s snapping, which requires IK and FK to have the same limits, so I wouldn’t mess with the default rigify setup, unless there’s some good reason.

[Mickey Ho]

Ok I understand. Thank you.

[Thomas Larsson]

The lHand bone already has a copy transforms constraints targeting lHandIK, so that automatically makes the forearms stretch. Although all of the stretching is done close to the wrist.

We need to remember that simple IK is just that; simple. The purpose is to add IK to the existing daz rig without adding lots of extra bones. Hence the deform bones and the FK bones are the same, which limits what can be done. If you need a more comprehensive rig, use MHX or Rigify.

[Alessandro Padovani]

@Thomas As explained above, to get ik stretch on/off it is enough to replace the copy transform with separate copy location/rotation. So this is a possible simple variation but of course it needs the control panel switch. Personally I believe ik stretch should always be on for animation, as in the current implementation. But ik stretch off can be good to better export daz poses, since daz studio doesn’t have ik stretch.

Let us know or I’ll close as “wontfix“ if you’re not interested.

[Thomas Larsson]

Sorry, I didn’t read properly. Sliders for IK stretchness are implemented in last commit.

[Alessandro Padovani]

Commit 941c414 works great here thank you for the nice update. If Mickey has nothing to add we can close as resolved.

[Thomas Larsson]

Actually it didn’t work fine, because the fk hands stretched to the ik hands even if ik was disabled. In the last commit the influence of the copy location constraint is the product of ik and stretchiness.

[Mickey Ho]

Well it works good enough for me, because I never use IK stretch. But yeah, this probably needs to be fixed because if the FK bones stretch to the IK bones, they get deformed permanently. Well not permanently, you can move the IK bones back to a distance where they won’t stretch, and snap the FK bones to them again.

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Going out of topic a little bit, may I ask why you think IK stretch should be always on for animation, Alessandro? I genuinely don’t know what IK stretch is used for.

[Alessandro Padovani]

@Mickey, the last commit works fine, you have to turn stretch on/off in the control panel. When you animate it is important that the ik goals stand still where you place them, and this can’t happen if you have stretch off. For example a hand may move when you move the rest of the body.