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IK is "bendy" after Convert to Rigify (Diffeomorphic)

RobinsonRobinson Posts: 751
in Blender Discussion

My IK chains seem to be "bendy", which I definitely do not want on my rig, after clicking the Convert to Rigify option in Diffeo's Blender plugin (1.6).  Conversely, if I go for Simple IK the bones aren't bendy but the Auto IK/X-Axis Mirror fails to work.  For the latter with Simple IK presumably I need a bone renaming option but I cannot find one.  For the former there must be a setting somewhere to prevent bendy bones, but I cannot find it.

Can anyone assist?

Comments

  • PadonePadone Posts: 3,688
    edited July 2021

    Rigify needs prebended bones for ik to work fine, that's not always the case with daz figures. So you need to check the "ik fix" option that will add limits where needed to prevent "bendy" issues. Also the figure must be at the default rest pose when imported.

    https://bitbucket.org/Diffeomorphic/import_daz/issues/498/important-fix-for-rigify-how-to-avoid-pose

    ik-fix.jpg
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    Post edited by Padone on
  • RobinsonRobinson Posts: 751

    Thanks Padone.

  • RobinsonRobinson Posts: 751

    The IK Fix option is checked and the bones are still bendy.  Did you mean uncheck it?

  • RobinsonRobinson Posts: 751

    The "solution" was to set IK Stretch on each of hands, feet to zero.  Bit surprised this is all default however.

     

  • PadonePadone Posts: 3,688
    edited July 2021

    Setting ik stretch to zero will not work, below there's an example with G8M. The solution is to use "optimize pose for ik" instead of "ik fix". See below for more details.

    https://bitbucket.org/Diffeomorphic/import_daz/issues/498/important-fix-for-rigify-how-to-avoid-pose

    ik-stretch.jpg
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    Post edited by Padone on
  • RobinsonRobinson Posts: 751

    Padone said:

    Setting ik stretch to zero will not work, below there's an example with G8M. The solution is to use "optimize pose for ik" instead of "ik fix". See below for more details.

    https://bitbucket.org/Diffeomorphic/import_daz/issues/498/important-fix-for-rigify-how-to-avoid-pose

    The "optimise pose for IK" is something I do every time and it didn't work.  Setting IK Stretch to 0 did work, so I'm not sure what that's about.

  • PadonePadone Posts: 3,688
    edited July 2021

    I believe we're talking about different stretchings then. The "long leg" stretch is what "ik stretch" is intended for, so you fix it by turning it off. But this is an intended rigify feature. The "short leg" stretch as shown above is a limit in rigify because it needs prebended joints for ik to work fine, and it is fixed with "optimize pose for ik".

    Then you did not post any picture of the stretch you want to avoid so I'm guessing here.

    Post edited by Padone on
  • RobinsonRobinson Posts: 751

    Padone said:

    I believe we're talking about different stretchings then. The "long leg" stretch is what "ik stretch" is intended for, so you fix it by turning it off. But this is an intended rigify feature. The "short leg" stretch as shown above is a limit in rigify because it needs prebended joints for ik to work fine, and it is fixed with "optimize pose for ik".

    Then you did not post any picture of the stretch you want to avoid so I'm guessing here

    It's the long leg stretch.  No clue why you'd want that on by default.  It's for cartoons.  Baffling.

  • PadonePadone Posts: 3,688

    Because you want control on hands and feet both in general and especially when they grab something. If you keep "ik stretch" off then hands and feet may move depending on how you pose the rest of the body. It is easier to fix a unwanted stretch than to fix sliding feet and hands.

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