View Full Version : keyframing IK
08 August 2007, 06:16 PM
This is my first attempt at rigging so please excuse if this is basic stuff. I tried to do a search on this forum, but i didn't really know what to search for...
I have a mechanical arm that has 4 segments. There are also 4 joints in the chain. I want to be able to animate an "unfolding" of the segments, then once they are all unfolded, I want to be able to control the arm with IK. I thought I could just keyframe the individual joint rotations to get the unfolding, and I found out I can, but once I try to keyframe the IK, the rotations stop responding to the keyframes i set. Is there any way around this? thanks!
08 August 2007, 07:01 PM
i think i may have figured it out using FK IK switch or something. If there's a better way than this, let me know. thanks again!
08 August 2007, 10:41 PM
yeah, one of the reasons for setting up rigs with nurbs curves and stuff is to get keys off of the joints themselves. you probably want some sort of fk/ik switch on an attribute so that you just key that attribute from 'ik off' to 'ik on' when you want to switch from fk to ik. there are tons of tutorials around for fk/ik switches. alternatively you could try using maya's built in fk/ik switch (it's the ikblend attribute on the ik handle) but some people don't trust it. either way you should set up some sort of rig so you're not keying directly on the joints, that's just asking for conflicts and buggy animation.
08 August 2007, 02:19 PM
thanks! how do you avoid keying the joints? i know you mentioned something about nurbs curves, but i'm not sure what you meant by that. All the tutorials i've read have had me keying the joint.
oh, and the fkik switch thing worked great!
08 August 2007, 03:42 PM
using nurbs curves is how you get a user interface for your rig. basically it allows you to control some complex things (like switching ik to fk) but do it all through the same controls. makes it faster and easier to animate, and if you do it right it's less susceptible to errors. the basic process is that you build a skeleton, create nurbs curves, and constrain the curves to the joints so that the joints are driven by the movement of the nurbs curves. then you can have complex actions tied to the nurbs curves using expressions or utility nodes (like i was saying about having an attribute switch between fk and ik).
some free rigs to peruse:
learning maya has a lot of links, i'm not sure how many of them work
rigging 101 has some tutorials:
and if you can spare some cash, definitely get 'the art of rigging' (start with volume 1)
08 August 2007, 05:37 PM
ahhh, i see. i think i saw a video of a facial rig using that method. Thanks for that, i'll definiitely look into those links and hopefully try out that method.
08 August 2007, 05:37 PM
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