Biasing an averave..

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Biasing an averave..

Biasing an averave..

2004-06-07 - By Raffaele "ThE_JacO" Fragapane

Back

Reply: 1 2 3 4 5 6

If the bones are curling too much you could be experiencing an axis screw up
due to some gimbal lockin, and it’s only normal that it’s more obvious in
the last bones of a chain, where the bones are rotating the most and getting
really close to locking.

Since you are working only on the Zaxis I seem to understand you could want
to change the order of rotation of your bones to a different order, maybe
one with Z on top of it, so that the axis will never overlap and Z will
drive the whole set.

Also bear in mind that constraints work on a global level, not local, this
means that rotations could have a different meaning to that bone then they
do on the reference chain.

In that case rotation orders properly set, and a set of expressions
including a bias variable (a slider in a CPset) could solve your problem.

Also remember that your 3rd chain is better off in FK mode, even if you
didn’t keyframe the effector.

Last but not least, since you are dealing with what is fundamentally a link
driven FK, you could also want to create your own hierarchy of objects and
setup of expressions, with centers set in the proper positions, rather then
using a chain.

More control and easier to troubleshoot.

I think that closely monitoring the orders of rotation and figuring out
what’s the axis orientation will cut you some beef.

Always work in add mode btw, at least you will see the correct axis
repositioning and can figure out locking issues with proper visual feedback.

~Raffaele Fragapane
~Freelance Technical Animator & TD
~Senior TA @ Peerless Camera

__ __

From: owner-xsi@(protected) [mailto:owner-xsi@(protected)] On Behalf Of
Jamie McDonnell
Sent: Monday, June 07, 2004 6:35 PM
To: XSI@(protected)
Subject: Re: Biasing an averave..

Cheers Raffaele...

I tried using constraints on a 6 bone chain, see I want each bone to be
blendable between an IK chain and a chain with the Spring Op on. It seems to
work fine for the firct 4 bones, then kinks at the 5th, non-comprehende!

I'll try using 2 x 3 bone chains and see if that works, any other
suggestions?

Cheers

Jamie

-- -- Original Message -- --

From: HYPERLINK "mailto:jaco@(protected)"Raffaele "ThE_JacO" Fragapane

To: HYPERLINK "mailto:XSI@(protected)"XSI@(protected)

Sent: Monday, June 07, 2004 2:05 PM

Subject: RE: Biasing an averave..

If you constrain the orientation of this 3rd bone to the other 2 the blend
of the second constrain is going to act exactly like a bias, with 0.5
averaging and anything below or over 0.5 moving toward one or the other
bone.

If constrains are not an option you are then looking forward to scripted
operators and slerping quaternions.

~Raffaele Fragapane
~Freelance Technical Animator & TD
~Senior TA @ Peerless Camera

__ __

From: owner-xsi@(protected) [mailto:owner-xsi@(protected)] On Behalf Of
Jamie McDonnell
Sent: Monday, June 07, 2004 2:59 PM
To: XSI@(protected)
Subject: Biasing an averave..

Afternoon all,

Great to see the new features in 4, soooo looking forward to owning a
copy... anyways...

I'm trying to create a Bias slider for an average of the z angle of 2 bones
onto a third.

This makes the Z angle of Bone C sit in the middle of bones A and B, I need
to find a way of biasing that average through a slider.

I hope I am having a dumb day and the answer is staring me in the face!

Cheers all

Jamie

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<div class=Section1>

If the bones are curling too much you
could be experiencing an axis screw up due to some gimbal lockin, and it&#8217
;s only
normal that it’s more obvious in the last bones of a chain, where the
bones are
rotating the most and getting really close to locking.<o:p></o:p>


<o:p> </o:p>

Since you are working only on the Zaxis I
seem to understand you could want to change the order of rotation of your bones
to a different order, maybe one with Z on top of it, so that the axis will
never overlap and Z will drive the whole set.<o:p></o:p>

<o:p> </o:p>

Also bear in mind that constraints work on
a global level, not local, this means that rotations could have a different
meaning to that bone then they do on the reference chain.<o:p></o:p>

In that case rotation orders properly set,
and a set of expressions including a bias variable (a slider in a CPset) could
solve your problem.<o:p></o:p>

Also remember that your 3rd
chain
is better off in FK mode, even if you didn’t keyframe the effector.<o:p><
/o:p>

<o:p> </o:p>

Last but not least, since you are dealing
with what is fundamentally a link driven FK, you could also want to create your
own hierarchy of objects and setup of expressions, with centers set in the
proper positions, rather then using a chain.<o:p></o:p>

More control and easier to troubleshoot.<o
:p></o:p>

<o:p> </o:p>

I think that closely monitoring the orders
of rotation and figuring out what’s the axis orientation will cut you some
beef.<o:p></o:p>

Always work in add mode btw, at least you
will see the correct axis repositioning and can figure out locking issues with
proper visual feedback. <o:p></o:p>

<o:p> </o:p>

<div>

~Raffaele Fragapane 
~Freelance Technical Animator & TD 
~Senior TA @ Peerless Camera<o:p></o:p>

</div>

<div>

<div class=MsoNormal align=center style='margin-left:36.0pt;text-align:center'>


<hr size=2 width="100%" align=center tabindex=-1>

</div>

From:
owner-xsi@(protected) [mailto:owner-xsi@(protected)] On Behalf Of Jamie McDonnell 
Sent: Monday, June 07, 2004 6:35
PM 
To: <st1:PersonName w:st="on">XSI
@(protected)</st1:PersonName> 
Subject: Re: Biasing an averave..<o:p></o:p>

</div>

<o:p> </o:p>

<div>

Cheers Raffaele...<o:p
></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

I tried using constraints on a 6
bone chain, see I want each bone to be blendable between an IK chain and a
chain with the Spring Op on. It seems to work fine for the firct 4 bones, then
kinks at the 5th, non-comprehende!<o:p></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

I'll try using 2 x 3 bone chains and
see if that works, any other suggestions?<o:p></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

Cheers<o:p></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

Jamie<o:p></o:p>

</div>

<blockquote style='border:none;border-left:solid black 1.5pt;padding:0cm 0cm
0cm 4.0pt;
margin-left:3.75pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt'>

<div>

-- -- Original Message -- -- <o:p><
/o:p>

</div>

<div style='font-color:black'>

From: <a href="mailto:jaco@(protected)"
title="jaco@(protected)">Raffaele "ThE_JacO" Fragapane</a> <o:p></o:p
>

</div>

<div>

To: <a
href="mailto:XSI@(protected)" title="XSI@(protected)">XSI@(protected)</a>
<o:p></o:p>

</div>

<div>

Sent:
 Monday,
June 07, 2004 2:05 PM<o:p></o:p>

</div>

<div>

Subject: RE: Biasing
an averave..<o:p></o:p>

</div>

<div>

<o:p> </o:p>

</div>

If you
constrain the orientation of this 3rd bone to the other 2 the blend
of the second constrain is going to act exactly like a bias, with 0.5 averaging
and anything below or over 0.5 moving toward one or the other bone.<o:p></o:p>

<o:p>
 </o:p>

If
constrains are not an option you are then looking forward to scripted operators
and slerping quaternions.<o:p></o:p>

<o:p>
 </o:p>

<div>


~Raffaele Fragapane 
~Freelance Technical Animator & TD 
~Senior TA @ Peerless Camera<o:p></o:p>

</div>

<div>

<div style='margin-left:36.0pt'>

<div class=MsoNormal align=center style='margin-left:36.0pt;text-align:center'>


<hr size=2 width="100%" align=center tabIndex=-1>

</div>

</div>

From:
owner-xsi@(protected) [mailto:owner-xsi@(protected)] On Behalf Of Jamie McDonnell 
Sent: Monday, June 07, 2004 2:59
PM 
To: <st1:PersonName w:st="on">XSI
@(protected)</st1:PersonName> 
Subject: Biasing an averave..<o:p></o:p>

</div>

<o:p> </o:p>

<div>

Afternoon all,<o:p></o
:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

Great to see the new features in 4,
soooo looking forward to owning a copy... anyways...<o:p></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

I'm trying to create a Bias slider
for an average of the z angle of 2 bones onto a third.<o:p></o:p>


</div>

<div>

 <o:p></o:p>

</div>

<div>

This makes the Z angle of
Bone C sit in the middle of bones A and B, I need to find a way of
biasing that average through a slider.<o:p></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

I hope I am having a dumb day and
the answer is staring me in the face!<o:p></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

Cheers all<o:p></o:p>

</div>

<div>

 <o:p></o:p>

</div>

<div>

Jamie<o:p></o:p>

</div>

<o:p> </o:p>

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<o:p></o:p>

<o:p> </o:p>

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<o:p></o:p>

</blockquote>

</div>

</body>

</html>
 

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