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mystikl

Using cloth attributes

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I'm new to Houdini, and I've been playing with cloth simulation for a few days now. I'm trying to paint stiffness on a grid but I can't figure out how to use the attributes like shellstretchstifness. The masterclasses are either for older version (I use H 14) or don't show the steps to setting up the attributes.

I've attached the file I've been working so you can tell me what I'm doing wrong and if you could fix it that would be even better.

Thank you.

TEST2.hip

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Hi and welcome :),

I am posting you a setup of painting stiffnes attribute. At first I paint desired pattern using Paint SOP. This node will create point vector attribute Cd. But Cloth solver requires shellstretchstiffness primitive float attribute. So I promoted Cd from points to primitives and copied value from red channel (doesn't matter which channel as I painted it in grayscale) to this attribute. Cloth solver then uses this value (I painted it from 0 to 1) as multiplier to parameters found in Cloth Object. I also changed bits here and there in your setup.

You can find more info in documentation.

 

Hope it helps,

Juraj

jt_paint_cloth_attribs.hipnc

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Hi and welcome :),

I am posting you a setup of painting stiffnes attribute. At first I paint desired pattern using Paint SOP. This node will create point vector attribute Cd. But Cloth solver requires shellstretchstiffness primitive float attribute. So I promoted Cd from points to primitives and copied value from red channel (doesn't matter which channel as I painted it in grayscale) to this attribute. Cloth solver then uses this value (I painted it from 0 to 1) as multiplier to parameters found in Cloth Object. I also changed bits here and there in your setup.

You can find more info in documentation.

 

Hope it helps,

Juraj

 

Thank you for your help, this whole node system Houdini has is a little too complicated for me. I managed to find a similar solution in an older topic, although I'm not sure if it is as good. Also I tried substituting paint with group, as I want to increase stiffness in the edges on the side, but I couldn't get it to work. Would your method be more suitable for this?

Shellstrongbendstiffness.hip

Edited by mystikl

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Hi,

both mine and your examples use similar way do define stiffness. It is so by painting areas that should be more stiff.

So if you want to have stiff edges you can either paint them using Paint node or select with Group node as in attached example.

In example I selected with Group node at first points on borders. Then I expanded previous group and converted it to primitive group. After that I specified stiffness multiplier on border primitives (from prepared primitive group) to be 1 and on the rest of geometry to small value (0.02).

 

Juraj

jt_group_cloth_attribs.hipnc

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Hi,

both mine and your examples use similar way do define stiffness. It is so by painting areas that should be more stiff.

So if you want to have stiff edges you can either paint them using Paint node or select with Group node as in attached example.

In example I selected with Group node at first points on borders. Then I expanded previous group and converted it to primitive group. After that I specified stiffness multiplier on border primitives (from prepared primitive group) to be 1 and on the rest of geometry to small value (0.02).

 

Juraj

 

This is great stuff, thank you once more. I noticed when I go in the DOP Network everything is greyed out, is there any way to access the settings?

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Houdini throws a few errors when opening  both files, the animation works though. I'm going to rebuild the nodes on a new file and see if it works.

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