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jkarian

Vellum sim collision offset problem

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Hi there,

I have a vellum simmed torus thats producing balls that stick to its surface.

I have a second vellum solver thats making the balls interact with the torus' surface and create dents.

It all seems to work fine except that there is a significant offset between the balls surface and the torus surface. 

Any ideas why?  Thanks in advance for your help.

image.thumb.png.9abaa229335fa2452ed880a02d20a71d.png

 

 

 

dentedBooleanVellum3.hipnc

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Looks like the thickness value isn't accurate? You can view the collision object's thickness in the dopnet. If you don't set your own thickness, I believe it defaults to 0.1 or something like this.

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I never like testing some theory using a complicated setup. So here's my very basic collision test. It looks pretty accurate to me. even at sim substep of 1

So obviously, your setup introduced other variables into the equation, trying to control a dozen different levers and setttings at the same time is a nightmare.

is all that vdb neccessary ? or pressure or pin to target ? or multi vellum solvers ? my guess is it's a combo effect of the pressure and 'soft' pin to target...and not inaccuracy of collision as my simple test shows.

VellumCollision.jpg

vu_VellumTestThickness.hiplc

Edited by Noobini

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Posted (edited)

i butchered your scene to a more simple version....looks like the growing balls are the problems, if I totally ignore your pointvop (pscale) and use static balls, they collide quite accurately.

 

VellumCollision2.jpg

Edited by Noobini

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Posted (edited)

this version is with growing balls

it's something to do with the copy Point Attributes, if i disable it, it works pretty good here. As said, I don't like debugging complicated file so here's my butchered version if you want to compare.

EDIT: def something dodgy with your pointvop pscale. You can have copy point attributes but add ^pscale in to exclude copying pscale, it will work.

 

VellumCollision3.jpg

dentedBooleanVellum_simple.hipnc

Edited by Noobini
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