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Throw and catch a ball with constraints in story.

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Message 1 of 10
dre4mer12345
1053 Views, 9 Replies

Throw and catch a ball with constraints in story.

So this seems like it should be fairly simple and work fairly well in MB but i'm having trouble getting it to work.

 

I have two characters, one throws the ball the other catches it. I have them both animated in story mode. Then I dropped a constraint track under each character with a parent/child contraint on each to constraint the ball to the hand control ball of each character at the appropriate time.

 

First character goes fine, when the constaint track starts the ball is locked to his hand when it ends the ball stops being locked to his hand. But when I start a second constraint track for the other character, a crazy offset is introduced into the first constaint. Even though the constrant tracks don't over lap. I thought this was the correct way to go about douing this so i'm not quite sure what's going on?

Any pointers?

9 REPLIES 9
Message 2 of 10
dre4mer12345
in reply to: dre4mer12345

It is very surprising that there isn't a tutorial about this somewhere online... if you aren't in story mode it's easy to see how to constrain an object to a hand, but as soon as you are in story mode I don't see any tutorials anywhere on this subject.

 

How hard could it be to have an object constraint to one character and then to another character in story mode. This is really frustrating and seems like a basic finctionality of a program intended to work with animated characters.

Message 3 of 10
Karen.Snow
in reply to: dre4mer12345

Hello,

 

For the constraints, there is a ‘Snap’ option to maintain the offset when you activate the constraint. However, I do not believe this is available in Story Constraint track or may work differently.

You can also apply normal constraint outwith Story mode for the prop object which might be an option.
Other things to look at would be using the Multi-Referential constraint.

If you would like to provice a scene example we could take a look at your setup.

 

Thank-you,

 

Karen



Karen Snow
Message 4 of 10
dre4mer12345
in reply to: Karen.Snow

Thanks for trying to help,

I've tried each of these constaint types and using snap, in story mode it seems like they don't turn off even though the constraint track with them in ends. So The first constraint works fine as does it's offset using snap, but if I add a second constraint to the same object (in a different constraint track) it messes up the first one even though they are in different constraint tracks that do not overlap.

Message 5 of 10
dre4mer12345
in reply to: dre4mer12345

After some more expirimentation, I can get the constraints to "work" in story mode. If I don't use snap, or keyframe any offset on the ball the constraint tracks work without messing anything up. HOWEVER since I can't make an offset the ball won't sit IN the hand. it's embedded in the wrist which is obviously unusuable. Since I thought the perpose of snap is to give an offset it seems like this should be working? 

 

Basically I can't use constraints in story with an offset on the constrainted prop.

Message 6 of 10
3dMastermind
in reply to: dre4mer12345

Hi Ethan,

I tested with Pepe and Mia in the story, plus a sphere that acts like the ball.
I then created an 'auxiliary pivot' on the correct hand inside the character controls for each character, (right click on the hand effector).
Then you can add several constraints on the same element (ball) in relation to the different aux. pivots and key the weight % inside the constraint.
Let me know if this helps.
When the weight goes towards zero, the balls local animation 'keys' takes over.


Perhaps you can set the ball offset that you need by modifying the auxiliary locator.

 

Also, please look at link below as I had another similar issue recently:
http://forums.autodesk.com/t5/motionbuilder-general/make-characters-lock-hands-together-in-story-mod...

Let me know if this helps.




Manny Papamanos
StingRay | MotionBuilder | Maya | Mudbox
Games QA Specialist



Message 7 of 10
dre4mer12345
in reply to: 3dMastermind

Would you be willing to record a little screen video of this working? Becuase I have been trying to for days and every single time the ball just get's an offset by the other constraint as if it's never getting turned off. I cannot get it to work and it's incredibly frustrating!

Message 8 of 10
dre4mer12345
in reply to: dre4mer12345

Alright nevermind I seem to have it working with a axilliary pivot which will let me place the ball more in the hand. So that is definately better than the ball sitting embedded in the wrist. I can't rotate the ball which since it's a football, is a bit problematic, but it should be passable for my use. (previs) 

It's about a 22 step process to have one character throw a ball to another seems like it could be easier 🙂 Who'd have thought it'd be so difficult to pass a ball...

Message 9 of 10

You have to keep in mind that the constraint tracks and constraints for that matter apply in the order they are in the story and in the navigator. If you are getting some strange offsets, it might be the order of calculation.
The other issue is you said you are using diffrent constraint tracks instead of keeping the constraints on one track at diffrent times?
You can animate the weight down on the conflicting tracks so that you don't have one track still active, while trying to work with a second track of constraints.

Last, the offsets work, you just have to make sure the constraint is locked so that the constraint doesn't keep calculating the offset while you are using it in story.

also you can stick an animation track in there and animate the ball even though it is constrained and locked and you can then blend this in to the constraint throw/catch movement.

example
constraint on -----blend off---animation ball throw/spin football)--blend on--catch constraint

throw in a third constraint for hand switching you can then blend to on the same track or on a diffrent constraint track.

Message 10 of 10

Here is a quick example tutorail on how to do this, hope it helps.

 

Rigging Dojo MotionBuilder #animtip Rigging Dojo- Brad Clark shows how to animate a ball throw and release with constraints in the Story window in MotionBuilder. http://autode.sk/12BDVO4

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