nCloth collision object one frame behind sim

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Old 01 January 2012   #1
nCloth collision object one frame behind sim

Hi

Can anyone tell me why when I create an ncloth simulation colliding with a geometry cached character that the passive body lags one frame behind the simulation.

I remember reading somewhere that "when" the collision was calculated could be changed.
Has this happened to anyone else and does anyone know how I can fix it?

I have worked around it by slipping the geom-cache ahead one frame but its a sloppy fix and I will be doing a ton if these sims.

thanks for any help or suggestions
Michael
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Old 01 January 2012   #2
I can't be more specific but does this perhaps have something to do with motion blur? There's a time sampling offset that can occur because of render passes/layers and how they can treat motion blur seperately ... although I may be completely wrong in pointing this out and it may only effect renders.
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Old 01 January 2012   #3
yah this isnt in a render environment the collision geo cached character is literally one frame behind the simulation. Ill spend some more time trying to resolve this. Thanks for your suggestion.
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Old 01 January 2012   #4
I seem to recall, but my alzheimers may be kicking in , that its just an openGL thing and in the sim itself its fine?

Duncan can answer, he has before
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Old 01 January 2012   #5
ok ill try and cache without the bump in timeline and see what happens thanks!
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Old 01 January 2012   #6
well I can confirm that it is not a display issue the collision object is in fact one frame behind the simulation. Any ncloth wizards I could sure use your help on this.

Thank you
Michael

edit..i searched for duncans posts and only found a reference to if the time scale was not set to exactly 1 a moving passive object would not calculate properly..my time scale is set to exactly 1
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Last edited by mandark1011 : 01 January 2012 at 06:25 PM.
 
Old 01 January 2012   #7
As you know ncloth can be finicky..would have to see the problem.... it could just be the scene, have you tried recreating it from scratch?

What kind of geo cache, maya, or inhouse? Are you sure ITS not off 1 frame?

Can you post something? Need more details..

Maybe if we say DUNCAN enough he will come, lol ....
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Old 01 January 2012   #8
haha thanks for answering HowardM.
no its standard maya stuff the whole way. Unfortunately i cannot post anything as im using the character from our show. I have found a less than elegant solution to fix it so im going with that as I have a ton of these to get through before i get to do the funner stuff, so head down and pump them out.
I did create a shot from scratch using primitives and didnt get the same result..worked as expected. thats why I thought it had something to do with the calculation order on deforming mesh. Its weird that it is exactly a frame behind.
cheers
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Last edited by mandark1011 : 01 January 2012 at 06:26 PM.
 
Old 02 February 2012   #9
Just an update to say that right now I'm having the exact some issue. Skinned mesh is a collision object and I've got cloth that's attached. The collision object is 1 frame behind when I view the collision mesh, although obviously the animation mesh seems fine.

No ideas :(
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Old 02 February 2012   #10
Had this problem a couple months ago. I take it the cached character is referenced? On the collision body, when solver display is set to collision thickness it lags behind as well?

What I did was to duplicate the collision geo so it is fresh and native in your scene(no connecions and no longer referenced), delete history, blend shape it from the original, create a fresh geo cache and convert the new cached geo to a passive collider. Not sure why it worked, but it did. LMK if it works for you, as I don't quite know why it was bugged for me like this.

- JP
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Old 10 October 2012   #11
I've had the same issue, using a referenced animated mesh which is driven by an in-house geo cache system. However it seems to only happen in the viewport. When I cache the nCloth objects and playblast with the cache the rigid collider the nCloth cache lines up correctly.
Makes it really annoying to cache and then playblast, as opposed to just doing playblasts to test different settings.
 
Old 10 October 2012   #12
Rule , geocache than simulation , no skinned , referenced geometry...
 
Old 10 October 2012   #13
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