Bones rotating, euler and quaternions i suppose. 2004-03-24 - By kim aldis
Back
Local rotations are misleading in that although you're producing what looks
like a local rotation, what's actually happening is that your local rotation
is being converted into a rotation relative to the parent - or scene if
there's no parent - behind your back. This results in misleading results
because the interpolation is running through angles you didn�t think you�d
keyed. Check out the values in the transform panel as you rotate in local
mode; rotate x, looks fine, rotate y, still looks fine, now add in some z
rotate. Ooops ....
My personal rules regarding rotations; 1. try and avoid working with local
rotations, for the above reasons; 2. never work with more than 2 axes - you
can rotate to any angle you wish using only 2 axes so why confuse the issue
by using the 3rd one which only messes everything up anyway; and 3. like all
rules, break 1 and 2 if you wish but be sure you have a good reason for
doing so, there are actually very few reasons.
If you must use local rotations you can do yourself some good by building a
3 null hierarchy above the object you wish to rotate, key one axis and one
axis only on each null. You'll not only see more clearly why Euler rotations
break so often, you'll also be able to change the rotation order easily.
> -- --Original Message-- --
> From: owner-xsi@(protected)
> [mailto:owner-xsi@(protected)] On Behalf Of Roberto Sarlenga
> Sent: 24 March 2004 13:02
> To: XSI@(protected)
> Subject: Bones rotating, euler and quaternions i suppose.
>
> Excuse this stupid question, but hwo can I avoid this problem:
>
> Create a bone.
> Make it FK.
> Key Rotation
> Rotate it in local Y
> Key Rotation
> Rotate it in local Z
> Key Rotation.
>
> Hit play and what it does is not what I did, and the axis
> doing what they want.
>
> Just in case my explanation wasn�t clear I attached the
> script for constructing the scene as txt
>
> I need the movements to be really precise.
>
> Thanks,
> Rob
>
> -- ---- ---- ---- ---- --
> Create3DSkeleton 2.21565731166908E-02, 0,
> -2.21673592161488E-02, 4.67503692762186, 0,
> -2.21673592161488E-02, 0, 1, 6.12303176911189E-17 DeselectAll
> SetAndToggleSelection "bone", , True InspectChainProperties
> SetValue "bone.chain.blendik", 0 SaveKey
> "bone.kine.local.rotx,bone.kine.local.roty,bone.kine.local.rot
> z", 1 SetValue "PlayControl.Key", 20 SetValue
> "PlayControl.Current", 20 Rotate , 0, -90, 0, siRelative,
> siLocal, siObj, siXYZ SaveKey
> "bone.kine.local.rotx,bone.kine.local.roty,bone.kine.local.rot
> z", 20 SetValue "PlayControl.Key", 30 SetValue
> "PlayControl.Current", 30 Rotate , 0, 0, 90, siRelative,
> siLocal, siObj, siXYZ SaveKey
> "bone.kine.local.rotx,bone.kine.local.roty,bone.kine.local.rotz", 30
> -- ---- ---- ---- ---- ---- ---
>
---
Unsubscribe? Mail Majordomo@(protected) with the following text in body:
unsubscribe xsi
|
|
