nCloth "rigidity" attribute breaking "append cache" functionality

#1

Hi all,
i’ve noticed that simply increasing the rigidity attribute (from 0 to 0.04) on nCloth simulation will cause “append cache” to messed up the resulting simulation.

here’s a simple test:
http://www.youtube.com/watch?v=k9KM2mD9Ms0&feature=youtu.be

on the upper part, i dialed the rigidity to 0.04 and sim-ed two times. the first time was continuous sim from start to end, and the second time was to append the sim at the middle of animation.
Notice that the sleeve movement changed dramatically when appending the sim, and caused unpleasant result.

on the other hand, when i set the rigidity value to 0, the resulting simulation from appending the cache at the middle of animation will be similar to continuous cache from start to finish.

I wonder if this is basically the limitation of rigidity attribute (non-appendable), or it is an unintended bug?

Jefri

#2

I avoid rigidity as much as possible. It’s a cool feature but i use it sparingly.

Have you tried setting the cache attributed to “Dynamic state”.
It’s a setting on the nClothShape
http://download.autodesk.com/global/docs/maya2014/en_us/files/nCloth_nodes_nClothShape.htm

#3

Yes, in that case I used “dynamic state”, and “World Space Output” on nCloth creation setting. Maybe it’s just that the rigidity attribute has plenty unintended side effects. I noticed that it might also cause the nCloth object to ignore collision on some passive colliders (in my case, a floor mesh) when using append cache.

#4

Cant completely remember, but isnt it buggy where if you try to append without first rewinding to the Sim Start Frame, it craps out?

#5

I found that trick a long time ago. Since then append has gotten better. “Ish”. This trick was to insure constraints were initialized. However that never worked for rigid appending.

And yes i find issues with Collision with rigidity as well. I will do anything i can to not use that feature unless it’s for a very simple specific reason. Deform resistance or a low res driver mesh are better options. If you plan to append.

#6

Yeah most of the time I also rewind to the first frame before doing append cache, to avoid the problem you guys mentioned above.
I think I’ll just avoid rigidity attribute for now. Using component constraints could achieve most of the effect similar to rigidity, though with heavier calculation time. Thanks for your feedback guys!

#7

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