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Animation moves when changing between FK and IK

Elsiehar 1 year ago • updated 1 year ago • 2

After setting the IK to FK the animation still moves when changing the blend from 0 to 1.  See video below.  I used the bind pose to set up the IK and it all looks correct.  Is this a problem with they way the character is set up?  

https://360.articulate.com/review/content/52f26bf3-6fd7-4bd6-8e11-b70deb3a5c17/review

As a work around I can sometimes separate the keys over a time period so it isn't as noticeable but it doesn't work all the time with some strange things happening in between.

Here is the other leg which is much worse.

https://360.articulate.com/review/content/07ef19ed-51ff-4015-8d2b-d689ff4e9639/review

Thanks

UMotion Version:
1.29p02
Unity Version:
2021.3.16f1

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Answer
Answered
Peter - Soxware Developer 1 year ago

Hi Elsiehar,

thank you very much for your support request.

IK has less "degrees of freedom". Meaning not every FK pose can be converted into the 100% same IK Pose. This is simply due to the fact that you can rotate bones in FK in a way you can't do with IK (e.g. rotate a bone around it's own axis).

Furthermore the FK to IK algorithm has to do some guessing work in order to get a similar looking pose but it won't always be 100% perfect.

So best is to not transition between FK to IK in situation where this transition is very noticeable.

Best regards,
Peter

Answer
Answered
Peter - Soxware Developer 1 year ago

Hi Elsiehar,

thank you very much for your support request.

IK has less "degrees of freedom". Meaning not every FK pose can be converted into the 100% same IK Pose. This is simply due to the fact that you can rotate bones in FK in a way you can't do with IK (e.g. rotate a bone around it's own axis).

Furthermore the FK to IK algorithm has to do some guessing work in order to get a similar looking pose but it won't always be 100% perfect.

So best is to not transition between FK to IK in situation where this transition is very noticeable.

Best regards,
Peter

Elsiehar 1 year ago

Thanks for letting me know.  I was using it for IK Pining, I ended up using the work around mentioned in one of the other discussions where I copy IK to FK for all the keys where I want the foot pinned.  It did the job:)

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