View Full Version : effector rotation

08-18-2003, 09:08 PM
I can't make the effector of a chain rotate.
I pose constrained it to a null (with a position offset), when I rotate the null the effector moves to follow the null's rotation but I need it to rotate on its own axis so that the entire chain rotates.
It works in Maya when I parent the ikhandle to a locator, but in XSI I can't parent the effector since it is part of the chain hierarchy (whereas the ikhandle in Maya is independant), that's why I used constraints.

I hope it is clear enough, if not tell me I will post pictures.
Thanks in advance for your help !

08-18-2003, 09:16 PM
please post a pic of what you are trying to do. XSI works (as you might have noticed) totaly different from maya when dealing with Effectors and IK.

So please explain what it is you are after and I'll try my best to guide you.

best regards

.stefan andersson

08-18-2003, 10:11 PM
Here is what I do in Maya :
The 2 ikhandles are parented to the box. When the box rotates the ikhandles move and rotate accordingly and so do the bones too.

Here is what I managed to get in XSI :
The 2 effectors are pose-constrained to the box. When the box rotates the effectors move but don't rotate since it is not a parent/child relation. So the bones don't rotate neither.

I am looking for a behavior similar to my Maya scene.

08-18-2003, 11:07 PM
ok, try the oposite. Parent the root's to the Cube and make two implicit cubes which the end effectors are position constrainted too.

I made a small MPEG file that shows the behavior.

Tell me if this could work for you.

best regards

.stefan andersson

08-18-2003, 11:33 PM
It was so simple !!!
Thanks very much StefanA, it works perfectly !:thumbsup:

It's not the first time you help me and I really appreciate this !


08-19-2003, 12:23 AM
I'm glad I could help you. Happy animating! :D


08-20-2003, 07:15 PM
wouldn't it have been easier to just contrain the orientation, with compensation on, on the effectors to the box?

08-20-2003, 09:24 PM
Sure LowJack, but it seems effectors just have position controls, not rotation, so it does not make the bone rotate.

I may be wrong but I didn't find how to achieve it. If you have a solution I am interested.

08-20-2003, 11:28 PM
just leave your setup as you first had it with effectors pose constrained to cube, then under the "chain" PPG for the bone/chain (not the effector), under Effector Rotation, uncheck, set to False, the parameter "Affected by last Bone"

08-21-2003, 08:50 AM
:applause: :applause: :applause:
ggg Thank you very much !!
You're my savior !

cheers ! :beer:

08-21-2003, 09:18 AM
Oops there's a problem...
The effector does rotate but not the bone. :banghead:

So I still need to use StefanA's solution which works perfectly.

08-21-2003, 08:40 PM
after turning off "effector rotation>effected by last bone"
-get a null
-transform>match all transforms, to effector
-translate null in local mode in one axis perpendicular to bone, likely Y
-parent the null as child to the effector
-select bone, skeleton>chain up vector and pick the null

(and if you have more than one bone in the chain its likely you don't want them to all rotate the same but rather blend between effector rot and and root rot, so look at MIsners Spline now available in XSI 3.5)

08-21-2003, 08:44 PM
Thanks you so much ggg !

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