View Full Version : FCurves, Keyframes, and Objects

07-10-2007, 01:40 PM
I'll start with my question, then give some background in case it isn't clear:
Suppose I have several objects selected, and I can see all of their curves in the FCurves window. Is there a way to tell which curve belongs to which object -- perhaps by selecting a keyframe and looking at some display?

Now for the background:

As a beginner with MotionBuilder, I don't always know how my entire rig will be affected when I keyframe a particular body part. Consequently, I end up with lots of keyframes on joints and body parts that can't be grabbed in the character control window.

For example, I might add two keyframes to the character's hand. Later, I go back and tweak the thumb a bit, but it doesn't act like I expect it to. If I select all of the nodes on the hands in the Character Controls window, I see only the keyframes that I set myself. If I drag a selection around the entire hand, I see a lot of keyframes in the FCurves window that I didn't set manually.

I'm sure I'll start to understand these heirarchies eventually, but in the meantime it would be very helpful to be able to locate the source of these stray keyframes.

07-10-2007, 11:00 PM
There's 3 different ways to set keyframes for body parts in MB. 1. Full body. 2. Body part and 3. selection.

Usually i set keyframes in bodypart mode. That way the keyframes are only set on the selected body part. If you set it in fullbody mode then keyframes are set for all the body parts even if you have, for example, the hand keyframed.

07-11-2007, 12:48 PM
There's 3 different ways to set keyframes for body parts in MB. 1. Full body. 2. Body part and 3. selection.

Yeah, I know about those. Some of my worst headaches finally disappeared when I learned about them :-)

The problem I'm having now is different, and I'm pretty sure it's related to IK vs. FK. I'm primarily animating the hands in IK -- not recommended, I know, but I'm actually building an animation layer on top of motion capture data from a set of Cybergloves. Complicated!

I'm finding that when I set keyframes on the IK handles for the fingers, MB sometimes generates "secret" keyframes on the FK finger joints. When I go back to change the IK keyframes, they don't behave like I expect because the FK frames are unaffected.

Could this have to do with the fact that I'm rotating the IK handles? It recently occurred to me that rotating from the fingertips might be interpreted as an FK action instead of IK.

Also, my original question still stands: can I find out which curve in the FCurves window goes with which selected object?

(Side note: I'm working on the same MoCap project as TuxedoPengu (http://forums.cgsociety.org/member.php?u=259682). Check out his past postings on the subject if you're into this sort of thing!)

08-01-2007, 10:57 PM
when you open a FC Editor there is a little drop down menu where you can choose group all, group by type and no grouping...when no groupin is selected it should display all the selected objects separatly and by clicking on the attributes you can view a specific curve for the specified object...
I hope this answers your question :) I'm not that sure I understood right but it seemed like this was your problem...

for the IK FK animation, I was banging my head against the wall one day to try to find how to manipulate FK keys in FCurve editor...there is a little trick that they just explain anywhere and it's such an important thing...in the Key controls panel under the animation menu you have to check "Display Keying Group" and then Keying group will appear in FCurve editor allowing you to manipulate FK keys also :)

hope this saves you from trouble :)

08-02-2007, 01:28 AM
That's awesome! I won't be able to try it out for a couple of days (I'm away from the software), but I'll be sure to look into those options as soon as I can. It sounds like you did understand my question just fine.


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08-02-2007, 01:28 AM
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