IK FK Blending 2004-07-06 - By Jamie McDonnell - Character Rigging / Animation TD
Back
Spot-on, thanks Bradley, I'll give that a try... How's life at ILM? Are they
keeping you busy over there?
Tar for now
Jamie
-- -- Original Message -- --
From: Bradley Gabe
To: 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
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<DIV><FONT face=Arial size=2>Spot-on, thanks Bradley, I'll give that a try...
How's life at ILM? Are they keeping you busy over there?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Tar for now</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Jamie</FONT></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
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<DIV style="FONT: 10pt arial">-- -- Original Message -- -- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=bgabe@(protected) href="mailto:bgabe@(protected)">Bradley Gabe</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=XSI@(protected)
href="mailto:XSI@(protected)">XSI@(protected)</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, July 06, 2004 10:11
PM</DIV>
<DIV style="FONT: 10pt arial"><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">
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<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
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