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Pelayo

Dealing with FEM + Static Body

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Good night, people:

I'm a newbie with Houdini. I've tried lots of tutorials but, I'm still having problems with collisions. I made a simple setup, a growing fem ball inside a static collider, but, it interpenetrates the walls of the static object.

I tried to get more substeps, to have more detail in collision guides, but I'm not sure what I'm doing wrong. I attach the file that I'm working on.

 

Thanks!

testme.hipnc

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Set "Local scaling" to "Use Local Feature Size" to have more accurate solidembed.
In "box_object1" set "Division size" to 0.05 or less. Change substeps to default 4 and 2 for collision.

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12 hours ago, fencer said:

Set "Local scaling" to "Use Local Feature Size" to have more accurate solidembed.
In "box_object1" set "Division size" to 0.05 or less. Change substeps to default 4 and 2 for collision.

Thanks fencer, it worked in this setup but... when I tried to work with thin walls in the collider object, again... it overlap again. Tried to raise sphere divisions and lower "Division size" in box_object1 but didn't make too much difference.

 

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18 minutes ago, Pelayo said:

Thanks fencer, it worked in this setup but... when I tried to work with thin walls in the collider object, again... it overlap again. Tried to raise sphere divisions and lower "Division size" in box_object1 but didn't make too much difference.

 

Make a screenshot of the problem area, maybe I do not understand what do you mean.

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12 hours ago, fencer said:

Make a screenshot of the problem area, maybe I do not understand what do you mean.

I tried your settings and that minimized the problem. But there's still some interpenetration of the sphere with the box. My idea was to finally do a thinner outer box, but when I try to do that, the inner sphere escapes from the box.

 

59e090d5aff14_Capturadepantalla2017-10-13alas12_06_47.png.9fd82b89bbcb2a949f378611874846db.pngUsing the thick wall sphere starts to overlap box.

59e090febe118_Capturadepantalla2017-10-13alas12_07_26.thumb.png.84203554a27eb7b19ac5be8dcc29c91b.png

 

If I try thinner walls:

 

59e09b54e3f21_Capturadepantalla2017-10-13alas12_53_31.thumb.png.53cd8fc4a5eb8fdf34d366c3e4b0dc58.png

Edited by Pelayo

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Hello, 

by raising your sphere division, your sim is more accurate but i takes more time to compute... and sometimes, the result is still not perfect ... and it seems you are in this case.

if i were you, i would keep your sim as it is , and after that, i would make some adjustements with sop point nodes to reduce overlapping. bellow 2 variations of the same method.

have fun with your muffin !
++

 

muffin-overlapping issue.jpg

testme-sop adjustements-ok++.hipnc

Edited by yglemarec
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21 hours ago, yglemarec said:

Hello, 

by raising your sphere division, your sim is more accurate but i takes more time to compute... and sometimes, the result is still not perfect ... and it seems you are in this case.

if i were you, i would keep your sim as it is , and after that, i would make some adjustements with sop point nodes to reduce overlapping. bellow 2 variations of the same method.

have fun with your muffin !
++

 

muffin-overlapping issue.jpg

testme-sop adjustements-ok++.hipnc

Thanks for this solution. I always though that solvers where more accurate and I was doing some bad setup.

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