Hello,

I am trying to create a paper deformation by using cloth. I fold the cloth and make it interact with a torus, but it always goes back to its original shape. If you imagine paper deformation: when you fold it and run through the fold with your hand, it doesn't stay as it was before. The fold will be strong and visible. But what my cloth simulation does is, that it goes back to its original shape after the torus runs through it. Am I choosing a wrong approach? Is the cloth not suitable to approach paper like simulation? I am also trying to achieve dynamically subdividing faces which are affected by the deformation, meaning: when the cloth is deforming too much, the faces which are being affected by the deformation will subdivide. How could I get the data that say how much the face is being affected by the deformation?
I am attaching a hip file, I hope it will be easier to understand what I am trying to do.

Thank you for your time :}

Hi,

For paper, I would recommend using the “Strong Bend” model.
In the Model tab of the Cloth Object, in the Relative Stiffness row, you'd set “Weak Bend” to 0 and “Strong Bend” to some non-zero value, for example 0.1.

The cloth recovers it's shape, because each piece of the cloth is trying to get back to its rest shape. The best way to create a fold is to change the rest positions over time, as in the attached example IntroduceFold.hip. The rest state starts out flat, and then the rest shape is gradually modified until there is a rest angle of 90 degrees at the fold.

To show how dynamic subdivision would work, I've added a simple example DynamicSubdivide.hip that applies a SOP solver to subdivide the cloth dynamically at frame 16.

Michiel

Hello,
thank you so much for the reply, help and hip files, they were really usefull!
I've tried the multisolver with sop containing subdividing, but when I add them all together, my paper doesn't react with other static objects. Basically, in my scene I have a ball which is scaling down and a paper inside it, which is getting compressed by this ball. I was thinking, that in the beginning of the animation, I would like to pass low poly paper to cloth solver (because it creates bigger more realistic folds). But then when paper is getting way too deformed, it topology would get subdivided, so there is more detail, more creases and intersection of faces would be eliminated. I tried applying your approach, but I think I am missing something. I've never used multisolver, so it is a bit confusing. I am attaching a file with my solvers, maybe it's just a small detail i missed.
Thank you again, I really appreciate your time :wink:

Thank you for posting your file.

The important thing to know here is that collisions with the cloth only happen in the exterior direction of your static object, which depends on your winding order. I applied a reflection transform that reverses the triangles on the sphere, so that the piece of paper would collide with the inside of the sphere.

Also, the uniform scale was animated on the object level, which should be avoided for DOPS. I moved this scale animation down into a transform inside the geometry network.

I added a somewhat simplified version of your file that shows the collisions working.

Michiel

Oh, that's perfect, works perfectly fine now. Thank you very much!!!