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Digit
07-24-2005, 11:58 AM
Hi,

My character needs to wear a very simple necklace, just a piece of string really, that needs to swing about her neck dynamically.

Im having real trouble making this work. I thought that making a curve dynamic would do the trick but the problem with that is that the curve isnt a real loop, so it just falls apart when it collides with her neck as though it had been untied.

Now Im trying soft bodies but im not having much luck there either, it always wants to spring off or do some crazy thing.

I guess Im no longer a Maya newbie but I certainly am new to dynamics. Ive searched and found a few similar threads but frankly, I ended up more confused by them.

Can anyone give me any help or advice on this? Maybe theres a totally different way of going about it.

Thanks in advance,

A

Sphere♥
07-24-2005, 05:09 PM
Hi Anais, yes a simple curve soft body with springs would make a simple "string" necklace. You could then extrude another little circle around that curve to give it body. Here's a simple curve soft body (paste into script editor & press ctrl+enter):
circle -c 0 0 0 -nr 0 1 0 -sw 360 -r 10 -d 3 -ut 0 -s 64 -ch 1;
soft -c;
spring -minMax true -mnd 0 -mxd 4 -useRestLengthPS true -s 20 -d 0.2 -sfw 1 -efw 1;

Attach it to a gravity field, then select the collision objects and select "Make Collide" under Particles. Make sure to adjust the geoConnectors' Resilience and Friction, try 0.5 for both initially.

Here's a quick playblast I just tried with the above:
http://www.putfile.com/media.php?n=necklace

There may be a better way... also could make a chain link with rigid bodies and hinges?

Digit
07-24-2005, 06:09 PM
Cheers Spheres! Awfully good of you to do all that for me and it looks like it could work just fine for me.

But I need to understand whats going on a little better.

So what you have done here is:
Create a nurbs circle
Make it a soft body.
Select the particles that just appeared and create a spring.
Select the particles and add gravity
Select the particles and some other geometry and Make Collide

Ok, when I do all that some unexpected things happen. Firstly on collision the particles go very bouncy and dont settle on the object. You refer to a geoConnector but I dont know what that is? Also Im not sure what the spring is doing here?

If you could help me on that I would be very grateful!

Thanks again

Digit
07-24-2005, 06:23 PM
Ok, I found the geo connector and that has stopped the bouncing... but, well, now everything else has gone crazy!

Any suggestions on how to make it look better than this:
http://www.putfile.com/media.php?n=playblast


Grrr, I hate working with dynamics!

Sphere♥
07-24-2005, 06:56 PM
Yes, what I did is basically what you wrote, except to be more precise it's not just one spring it's a bunch of springs, 256 in this case. The springs hold the necklace (particles) together. In that playblast you posted, was that necklace created from the script I provided? It does look like there is something wrong with the springs (not properly set up)? Or perhaps the collisions are sticking(not enough particles or tessellation for collision)? I tried putting the script necklace through more torture and it doesn't break/stick like that on my PC? Sorry for the frustration.

Digit
07-24-2005, 07:22 PM
I used your script first and then I recreated it step by step - obviously Ive done something wrong somewhere!

Im thinking it might be something to so with scale? Your nurbs circle has a radius of 10 but i need it much smaller - does that affect things?

Also, its all moving so slowly as though its underwater.

Ive struggling all day with this - starting to wonder if my heroine is going to have to lose her necklace!

Any ideas? Please dont go out of your way though...

Sphere♥
07-24-2005, 07:48 PM
Well I understand your frustration, Maya dynamics seem to be a lot of trial and error.

Yes, scale would come into play. When use Maya dynamics I try to keep all my objects sized in cm, since the dynamics defaults are geared to that (for cloth especially). I guess if you are working at a smaller scale you would need to change the gravity field's magnitude and probably increase tessellation for colisions to the max (also found in the geoConnectors). It's a good thing to have more particles than not enough too, so when you create your nurbs circle give it a high enough subdivision since "Make soft" will put a particle at each subdivision. Since the scale is different you might need to adjust the springs' stiffness and damping. As well the MinMax springs I used are not necessarily ideal... trial and error. :sad:

What about a solid silver ring necklace (rigid body torus), that might be easier?:D

Digit
07-24-2005, 08:16 PM
What about a solid silver ring necklace (rigid body torus), that might be easier

I have been considering it!

What is confusing is the sheer amount of options! You never can tell what combination of options would make the crucial difference.

Well, everything you said has made sense to me so I will give it all a try. But now Im tired and am gonna give it a break for today. At least I feel Im on the right track now anyway...

Thanks so much for your help, I really appreciate it!

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07-24-2005, 08:16 PM
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