Prevent skewing with bone rotation

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isby
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Joined: Thu Feb 02, 2017 1:25 pm

Prevent skewing with bone rotation

Post by isby »

Hi guys,

I've been at this for a while. I have a character rig that I've hooked onto mocap and all is well: I have a hip, a chest, two elbows and two fists tracked and I'm getting an interesting result as I track target bones to the mocap tracking.
However, there is one point that' busting my b****... Whenever a shape gets rotated, it also gets skewered. It's very time consuming to fix it manually, almost completely removing the benefits of the mocap.
So let me illustrate the problem.
Image
This is the 0 position.

Once I rotate it, the face get elongated.
Image

Is there a way to keep the original ratios?
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synthsin75
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Re: Prevent skewing with bone rotation

Post by synthsin75 »

It looks like you have a flattened targeted pin bone in the first image: https://drive.google.com/open?id=0B_Wv8 ... 0s0X1VLOGs

That would seem to indicate that you have the bone layer or one of it's parent layers rotated on the x-axis. That would cause the skewing when rotated.
isby
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Re: Prevent skewing with bone rotation

Post by isby »

Hm, thank you. How would I check that? u
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synthsin75
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Re: Prevent skewing with bone rotation

Post by synthsin75 »

With the Rotate Layer XY tool selected, select through the layers and make sure the X rotation is zero.
isby
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Re: Prevent skewing with bone rotation

Post by isby »

Unfortunately, no. I've tried all the layers and they're all set at 0. I thought for a moment this was happening because I was using points but I insertedan image andgot the same result. It's the 2d rotation created by bones that messes it up
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synthsin75
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Re: Prevent skewing with bone rotation

Post by synthsin75 »

isby wrote:Unfortunately, no. I've tried all the layers and they're all set at 0. I thought for a moment this was happening because I was using points but I insertedan image andgot the same result. It's the 2d rotation created by bones that messes it up
That doesn't explain why your pin bone is squashed. Maybe your camera is tilted.

Might be easier to diagnose if I could see the file.
isby
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Joined: Thu Feb 02, 2017 1:25 pm

Re: Prevent skewing with bone rotation

Post by isby »

Squashed as in just a circle? It's because when creating the tracking bones, I don't drag the bone out, I just click on the canvas, and get an orb. I was just checking it in Orbit view and it seems to be a 3d orb
isby
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Joined: Thu Feb 02, 2017 1:25 pm

Re: Prevent skewing with bone rotation

Post by isby »

isby
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Joined: Thu Feb 02, 2017 1:25 pm

Re: Prevent skewing with bone rotation

Post by isby »

Aaaah, I get what you're asking me now. I've gotten so used to it that I forgot it was squashed in that direction. It's sqashed because I've squashed the entire layer vertically when doing video tracking. Let me see if fixing that has any effect.
isby
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Joined: Thu Feb 02, 2017 1:25 pm

Re: Prevent skewing with bone rotation

Post by isby »

No, it doesn't fix my original problem, the character just get elongated.
isby
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Joined: Thu Feb 02, 2017 1:25 pm

Re: Prevent skewing with bone rotation

Post by isby »

OK; your comment made me start watching the bones rather than the points.
So I think my proper question here is why does the head bone on image 2 get stretched compared to the original position, i.e. can I prevent it from doing that when in rotation?
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synthsin75
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Re: Prevent skewing with bone rotation

Post by synthsin75 »

That squashed layer is your problem.

As a general rule, I never do layer transforms while designing characters. Only while animating them. You can end up with problems like you're having, trouble matching stroke widths, etc..

Your first problem sounds like your mocap reference doesn't fit your character's desired proportions.
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