 | | | IK FK Blending | IK FK Blending 2004-07-06 - By Bradley Gabe
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I'm glad it's working for you. :-)
I have talked to the folks at Softimage about this specific issue, and
it looks as though it's still present in XSI 4.0. As long as the
preferred rotation angles are being used to store FK rotation data, the
built in IK/FK blending is not going to function in a satisfactory
manner as a reliable animation control system. However, it does serve a
useful purpose as a quick, temporary solution in case of emergency.
Just to be a squeaky wheel and verify that it's been logged, I'm cc'ing
this thread to support. ;-)
-Brad
> Worked like a charm, cheers Brad!
>
> Jamie
>
> -- -- Original Message -- --
> *From:* Bradley Gabe <mailto:bgabe@(protected)>
> *To:* XSI@(protected) <mailto:XSI@(protected)>
> *Sent:* Tuesday, July 06, 2004 10:11 PM
> *Subject:* Re: IK FK Blending
>
> The main problem with XSI's built in IK-FK blending is that it
> stores the FK rotations in the preferred angle parameters, which
> means your keyframed FK animation will affect which quadrant the
> IK calculations solve for. Therefore, as long as you stay within
> the same 90 degrees of your IK solve, you shouldn't get any
> flipping or jitter issues.
>
> If you're going to use the 3-chain technique, make sure the chain
> that is being blended between the IK and FK chains is split into
> separate, single-bone chains (I only use multi-bone chains to do
> IK solving). I tend to use a pose constraint on them (which is
> faster than an orientation constraint) and use the built in
> constraint blending to do the mixing. It works like a charm.
>
> -Brad
>
>
>> Hi guys
>>
>> I have asked this once this morning, so please excuse my
>> repeating the question but I promise it has evolved from earlier...
>>
>> I gather from reading xsibase posts etc that the IK / FK blending
>> on standard bones is not great, but does anyone know a workaround
>> that will allow me to blend between FK of an elbow joint bending
>> back on itself, and an IK punching motion? All I seem to get is
>> pops and snaps when trying to blend between the 2 motions. I know
>> I could put them on the mixer, but I need a true IK - FK blender
>> to animate with...
>>
>> Which led me to set up the 3 chain IK - FK rig, IK chain,
>> Result, FK chain, expressions as clips on the mixer driving the
>> rotation / roll / upvector angle, but the 2nd bone in the chain
>> doesnt update until I change the frame...
>>
>> Any thoughts sure would be appreciated...
>>
>> Cheers all
>>
>> Jamie
>
>
>--
>Bradley R. Gabe
>Industrial Light & Magic
>
>
--
Bradley R. Gabe
Industrial Light & Magic
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I'm glad it's working for you. :-)<br>
<br>
I have talked to the folks at Softimage about this specific issue, and
it looks as though it's still present in XSI 4.0. As long as the
preferred rotation angles are being used to store FK rotation data, the
built in IK/FK blending is not going to function in a satisfactory
manner as a reliable animation control system. However, it does serve a
useful purpose as a quick, temporary solution in case of emergency.<br>
<br>
Just to be a squeaky wheel and verify that it's been logged, I'm cc'ing
this thread to support. ;-)<br>
<br>
-Brad<br>
<blockquote type="cite"
cite="midBAY17-DAV160WRKFLfP00077b72@(protected)">
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<div><font face="Arial" size="2">Worked like a charm, cheers Brad!</font><
/div>
<div> </div>
<div><font face="Arial" size="2">Jamie</font></div>
<blockquote dir="ltr"
style="border-left: 2px solid rgb(0, 0, 0); padding-right: 0px; padding-left:
5px; margin-left: 5px; margin-right: 0px;">
<div
style="font-family: arial; font-style: normal; font-variant: normal; font
-weight: normal; font-size: 10pt; line-height: normal; font-stretch: normal;
font-size-adjust: none;">-- --
Original Message -- -- </div>
<div
style="background: rgb(228, 228, 228) none repeat scroll 0%; -moz-background
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initial; font-family: arial; font-style: normal; font-variant: normal; font
-weight: normal; font-size: 10pt; line-height: normal; font-stretch: normal;
font-size-adjust: none;"><b>From:</b> <a
title="bgabe@(protected)" href="mailto:bgabe@(protected)">Bradley Gabe</a> </div>
<div
style="font-family: arial; font-style: normal; font-variant: normal; font
-weight: normal; font-size: 10pt; line-height: normal; font-stretch: normal;
font-size-adjust: none;"><b>To:</b> <a
title="XSI@(protected)" href="mailto:XSI@(protected)">XSI@(protected)</a
> </div>
<div
style="font-family: arial; font-style: normal; font-variant: normal; font
-weight: normal; font-size: 10pt; line-height: normal; font-stretch: normal;
font-size-adjust: none;"><b>Sent:</b>
Tuesday, July 06, 2004 10:11 PM</div>
<div
style="font-family: arial; font-style: normal; font-variant: normal; font
-weight: normal; font-size: 10pt; line-height: normal; font-stretch: normal;
font-size-adjust: none;"><b>Subject:</b>
Re: IK FK Blending</div>
<div><br>
</div>
The main problem with XSI's built in IK-FK blending is that it
stores the FK rotations in the preferred angle parameters, which means
your keyframed FK animation will affect which quadrant the IK
calculations solve for. Therefore, as long as you stay within the
same 90 degrees of your IK solve, you shouldn't get any flipping or
jitter issues.<br>
<br>
If you're going to use the 3-chain technique, make sure the chain
that is being blended between the IK and FK chains is split into
separate, single-bone chains (I only use multi-bone chains to do IK
solving). I tend to use a pose constraint on them (which is faster
than an orientation constraint) and use the built in constraint
blending to do the mixing. It works like a charm.<br>
<br>
-Brad<br>
<br>
<br>
<blockquote cite="midBAY17-DAV13gQkdzgXO00062ac5@(protected)"
type="cite">
<meta content="MSHTML 6.00.2800.1400" name="GENERATOR">
<style></style>
<div><font face="Arial" size="2">Hi guys</font></div>
<div> </div>
<div><font face="Arial" size="2">I have asked this once this
morning, so please excuse my repeating the question but I promise
it has evolved from earlier...</font></div>
<div> </div>
<div><font face="Arial" size="2">I gather from reading xsibase
posts etc that the IK / FK blending on standard bones is not
great, but does anyone know a workaround that will allow me to
blend between FK of an elbow joint bending back on itself, and an
IK punching motion? All I seem to get is pops and snaps when
trying to blend between the 2 motions. I know I could put them on
the mixer, but I need a true IK - FK blender to animate with...</font></div>
<div> </div>
<div><font face="Arial" size="2">Which led me to set up the 3
chain IK - FK rig, IK chain, Result, FK chain, expressions as
clips on the mixer driving the rotation / roll / upvector angle,
but the 2nd bone in the chain doesnt update until I change the
frame...</font></div>
<div> </div>
<div><font face="Arial" size="2">Any thoughts sure would be
appreciated...</font></div>
<div> </div>
<div><font face="Arial" size="2">Cheers all</font></div>
<div> </div>
<div><font face="Arial" size="2">Jamie</font></div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Bradley R. Gabe
Industrial Light & Magic
</pre>
</blockquote>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Bradley R. Gabe
Industrial Light & Magic
</pre>
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