View Full Version : Animating a chain with two nulls?

Thomas M.
08-25-2004, 05:48 AM
Hi everybody,

don't know if I'm getting senile or if I just miss something.

I want to animate a poly-chain with MD dynamics. Well, you can set up 1 fix-point (surface) to let the chain swing like a rope in a Tarzan movie. But what do I do when I want to animate both endpoints? Can I parent the endpoints to a null? That should be possible, somehow, pleeeaaase!!!

Can anyone help me out? There must be at least one trick.

Thanks to everyone who's willing to share.

08-25-2004, 05:59 AM
There's a reference object field in the MD controller (under the surface/part attributes) Just make that surface fixed, and select the null you wish to control that fixed part in the Reference field.

08-26-2004, 11:43 AM
Exactly! You create fixed surfaces at each end and then assign reference objects to them. Its sort of like IK for MD. :)

08-26-2004, 12:28 PM
Is this the same in LW8? I can't seem to find a "reference object" field in the dynamics panel when using ClothFX.

08-26-2004, 12:36 PM
No, that seems to have been removed from the cloth dynamics as well as multithreading...dont know why. You can still use MD in LW8 though. :)

08-26-2004, 12:40 PM
Do you mean install the plugin from 7.5 into 8? Because, I cannot find Motion Designer in the deform or motion plugins anymore.

Thomas M.
08-26-2004, 12:41 PM
So how is it done in 8 and with ClothFX? Would be nice to know it for the future.

Thanks so far for the replies.

08-26-2004, 12:48 PM
I would surmise they want you to do it with bones now. :shrug:

One at each area of the 'fixed' zone would do it, right? Kind of like doing lighting/electricity with 2 point polys is what I envision.

Thomas M.
08-26-2004, 01:00 PM
Bones? Sounds like Lightwave 5.6.

I did want to animate an umbrella opening and closing and already wrote the expression for it. Having all the pieces on different layers would make it impossible to work with ClothFX as there seems no chance to parent the cloth to the different structure elements.

Why did the get rid of MDs functionality in ClothFx? Drawbacks in an upgrade? Kind of strange.

08-26-2004, 06:40 PM
Do it with bones and weight maps. Put a bone in for every different fixed area, and give that bone a weight map for that fixed area. Then animate the bones.
Make a fixed weight map for all the fixed areas combined and apply that in the fixed area of cloth fx. That should give you what you want.

Alternatively use sock monkey and weightmaps or selection sets. It's all good.

08-26-2004, 07:40 PM
I dont know why MD is multithreaded and Cloth isnt.
Its strange that the simple process of using reference objects was removed.
Having to resort to bones or sockmonkey is a kludgy way of dealing with this.

10-25-2004, 07:02 AM
I'm joining this a couple of months after the fact, but...

There's a couple of demo's in LW 8's content/dynamics directory.
3cables-calculation & 3cables-playback.

I've been wondering about how these things are supposed to work, which is why I did a search and found this thread. If LW8 can't calculate this sort of thing in dynamics (attaching two ends of an object to two different parents), why on earth are these two examples available in the dynamics directory?

To compound the problem, the example given in 3cables-calculation, which I would have thought would have given the basic objects setup, leaving it to the user to run the calculation, is nothing of the sort. It actually uses precalculated motions without giving any clues as to how the motions were calculated in the first place???

Other than going back to MD, or using other plugins (aka worleys polk or taft), has anyone found a way of calculating this sort of thing with LW8's dynamics?

10-25-2004, 09:54 AM
Use bones and weightmaps as I suggested for the fixed parts, then run cloth FX on the soft bits.

Did you come to the LW N user group meeting? If not, WHY NOT??? :)

You'll get to meet some of the other users on this forum and yak your head off :)

10-25-2004, 10:55 AM
Here's a little demo...

10-25-2004, 11:28 AM
Well bless your cotton socks Sir.

Just got back in and was thinking about using your bones suggestion on the drive home. Was trying to avoid it if possible, but what the heck, great demonstration.

As soon as I get the time I'll see if I can get down to one of the meetings. If it's in Leeds (60 mile trip), I'll have to plan ahead. Don't think I've ever been to Leeds and not popped in to a local, so driving's out. :)



03-12-2006, 11:14 PM
Hey dodgy
Thanks for your example with the boxes and floppy tube..Looks real cool..Had a fair amount of trouble breaking it down but finally got there, and made my own version using a chain and two balls looks cool..
Thanks bloke.

03-13-2006, 03:06 AM
No worries :)