Unwanted rotation or movement after ncloth inflation

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

THREAD CLOSED
 
Thread Tools Search this Thread Display Modes
Old 07 July 2009   #1
Unwanted rotation or movement after ncloth inflation

Hello fellow cgtalkers

The title says it all:

With gravity removed from the nucleus; I pump pressure into a ncloth object, yet without any constraints or fields, the object drifts away, has some rotation to it. I'd like the shape to stay put.



It is a perfectly symmetrical mesh. I've tried nconstraints to no luck

Any help ?


Than you, and have a good day.
__________________
maya@reddit r/maya
 
Old 07 July 2009   #2
turn down/off your Lift setting.... could also turn up Damp, Drag, etc...
__________________

.

Reel - 3DInk.com
Filmography -IMDB
R&D - VIMEO

*please read- cyanbsl.blogspot.com/*
 
Old 07 July 2009   #3
thank you... that and nconstraints worked


edit: hefty work shown on your website, impressive!
__________________
maya@reddit r/maya

Last edited by berniebernie : 07 July 2009 at 01:18 PM.
 
Old 07 July 2009   #4
The solver normally does stretch evaluation sequentially which creates stronger stretch resistance for a given number of iterations, but results in a bias(that causes this drift because the stretch fights against the pressure). You can avoid this by making the nCloth evaluation order "Parallel". It will then be more stretchy and you will need less pressure to inflate( or need to pump in less air ) and also should no longer drift. You can imagine that a cloth balloon made out of something like nylon or silk would require tremendous air pressure to make it stretch and expand( the stretch resistance of rubber would be much lower ). In generally it is easier for the simulation( if you want to blow up a balloon ) to keep the cloth stretchy (low stretch resistance value). However note also that technically the default values for stretch resistance and pressure incompressibility are quite low... more like balloon rubber and a very thin gas. But as long as the relative difference is the same then keeping them low will allow you to simulate with fewer iterations and substeps( faster ).

Duncan
 
Old 07 July 2009   #5
Try to use instead of poly sphere, subds sphere, convert to polygons.
This will have more even spread of points, so more even forces too...
Compare and you will see what I mean...

Als
__________________
"No Bucks, NO Buck Rogers!"

VFX rule no. 387
# Just redo it!

 
Old 07 July 2009   #6
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
__________________
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
 
Thread Closed share thread



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
CGSociety
Society of Digital Artists
www.cgsociety.org

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump
Miscellaneous

All times are GMT. The time now is 02:14 AM.


Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.