CGTalk - Constraing without getting green channels

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Fletcheroso

01-14-2009, 01:51 AM

I'm having a little trouble setting up a proper constraint for an animation where a character picks up an object and then sets it down. I am well aware of the key visibility and parent to joint method, but I want to learn to use the constraint method.

So what I've done is created and keyed animation on an IK arm.
Then, at the frame where he grabs the object, I snap a Locator to the object,
then I parent constrain thr IK handle to the locator
(this is where th IK channels turn green, indicating both a constraint and keyed animation)
Then I parent the locator under the object.
Then I change the Blend Parent channel to turn on and off the constraint.
Then I use the object to move the characters hand.

So, with regard to the green channels, the only thing I can think to do is delete all the animation and repose the arm in FK.
Anyone have any suggestions?

DruG

01-14-2009, 06:46 AM

I don`t get it, what`s your question? :)

Fletcheroso

01-14-2009, 08:07 AM

Well, my question is how do I create a constraint between object and hand without turning the IK handles' channels green?
If that's not clear, I'll just ask you this:
How would you constrain a prop to a character's hand?
(Without using the dual-prop key visibility method)

DruG

01-14-2009, 10:23 AM

When I`m constraining I ALWAYS constrain the parent of my object. I mean I just group my controller which makes another tranform node for it and then I constrain that node. That way I have independent transform node, without green channels:)

JoshBowman

01-14-2009, 10:50 AM

I realise you posted this topic to learn the constraint method of grabbing an object but I thought i'd direct you to a couple of little scripts that will just do it automatically without all the constraint bizzo.

They are:

grabAnim (http://www.highend3d.com/maya/downloads/mel_scripts/animation/grabAnim-1206.html) and Snaps (http://www.highend3d.com/maya/downloads/mel_scripts/animation/snaps-1208.html).

basically you stick both of them in your scripts directory, assign grabAnim(); to a shelf button, select the driver object, shift select the driven object, highlight the amount of time you want them to stick together in the timeline and click the button and wham, the object will stick exactly where it is in relation to the driver object on the first frame of your selection, for however many frames you specify (the script keys every frame in the range).

If you aren't interested in this, my apologies for hijacking the thread, I just wanted to make sure you were aware there was an easier way.

DruG

01-14-2009, 11:17 AM

JoshBowman, thanks, those are awesome:)

I think it`s important to understand what`s under the hood, but when it comes to production scripts like these are real time savers.

Fletcheroso

01-15-2009, 08:13 AM

Thanks DruG, I'll try to experiment with the hierarchy to constrain the parent rather than the object. Also, thanks JoshBowman for the scripts, I will try them out. I think that prop constraints must be a common question among young animators and it would be good to hear about many different methods.
Also, I should apologize for not mentioning the software I'm using which is Maya, and I should also apologize for mispelling constraining in the title!

DruG

01-15-2009, 05:00 PM

I think it was quite clear for maya users when you mentioned "green channels", so no worries;)

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