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View Full Version : Maya Character Rigging - IK doesn't follow the arm

JDower
12-11-2010, 02:44 PM
Hi all.

I'm new to this community but have been lurking for a while. I'm a second year university student with roughly 2 years experience with Maya. For an assignment I have to model/rig a singer. I've been following a book called 'An Essential Guide to Maya Character Rigging' and up to now it's been going well.

I have my character pretty much fully rigged with an IK/FK arm setup. However I have run into a problem; when I rotate the body or move it using anything other than the master controller, the IK joints do not follow, which is going to cause me problems when animating. When I switch to IK mode from FK, the arm moves to where the IK joints have stayed.

I have a feeling this has something to do with when I set preferred angle on my IK arm. The book is designed for Maya 2008 but I am running Maya 2011. Are the default settings for Maya 2011 different from the Maya 2008 Set Preferred Angle? The default settings are set to Hierarchy and not Selected Joint. Does the Maya 2008 version differ from this? I'm asking because I know the default settings for the IK Handle Tool are different in Maya 2011 where it's ikSCsolver as the default instead of ikRPsolver in 2008.

The FK joint follows the arm as it should, but for some reason the IK doesn't. I have followed the book to the letter and can't quite understand what's gone wrong. Here are some screen shots to show my problem.

http://img528.imageshack.us/img528/5271/ikproblem1.png

The joints at the back is the IK arm which does not follow the original arm like the FK does.

http://img571.imageshack.us/img571/228/ikproblem2.png

When I switch to IK mode, the arm snaps to where the IK arm is.

Any help or advice would be great!
pearblossom
12-13-2010, 04:23 PM
The IK joints are controlled by the ik handles, which are probably parented/connected under the master control, hence they are following the master control. The whole point of ik is that it is an inverse hierarchy, as opposed to FK where the position/rotation of the parent affects the position/rotation of the child. If you would like your ik handles to be following a different control, then you can create an empty group above the ik handle control and point-constrain it to various different spaces--ie., the world, hip and chest controllers--then you can switch between them. There are a number of books and tutorials that will probably explain that a lot more clearly than I am here.. googling 'space-switching' might turn up some useful stuff.
JKrause
12-13-2010, 05:24 PM
IK arms and legs move independently of the body so that the character can plant his hands or feet on an object, such as a door knob or the floor, without having to constantly counter-animate against any moves in the body. It sounds like your character is working just as he should.
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12-13-2010, 05:24 PM
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