Help New User Need Help

[Notreturn]

Hello.
I want to do ironing sytem with using Obi Cloth.
First i need to create wrinkled fabric and then when i put iron on the fabric i want the fabric to be flat.
How can i start with? Or Can i do it with the Obi cloth.
Any help will be appreciated.

[josemendez]

Hi there,

You can use ObiCloth for that, but it sounds like overkill to me unless you want extremely detailed and precise behavior.

A piece of cloth that's flat on a surface (ironing table) has not much cloth dynamics going on. It's basically static.

So much simpler approaches would be good: for instance, move vertex positions towards the ironing table surface and recalculate the fabric normals. This can be easily done in Unity without any third-party physics engine, simply raycast to check which vertices are under the iron, then flatten them out and call mesh.RecalculateNormals().

[Notreturn]

Thank you so much for precious and fast answer.
So as i understand you mentioned about mesh deformation?

another thing. What if i put obi colliders under the facric and give the fabric wrinkled effect and push these collider when moving the iron?

[josemendez]

Thank you so much for precious and fast answer.
So as i understand you mentioned about mesh deformation?

Yes. Simply flattening vertices under the iron, and recalculating normals would be enough.

another thing. What if i put obi colliders under the facric and give the fabric wrinkled effect and push these collider when moving the iron?

Would accomplish the same effect, but would be orders of magnitude slower. Cloth simulation is very expensive, I don't think it would be needed in your case. There's cheaper, simpler ways to achieve the same like the one I explained.

[Notreturn]

Thank you so much i am really appreciated.

[Notreturn]

Hello Again. Sorry to Disturb you many times.

*reference to first obi cloth tutorial(Flag)*
I have created blueprints.
Add cloth_sheet mesh to the blueprint etc. and create a flag as yours and works great.
But what if i want to add a car or shoes or pants meshes etc. I tried many meshes instead of cloth_sheet mesh and result was like meshes are split and not look like anything. Thanks Again.

[josemendez]

But what if i want to add a car or shoes or pants meshes etc. I tried many meshes instead of cloth_sheet mesh and result was like meshes are split and not look like anything. Thanks Again.

If your mesh is composed of multiple, disjoint pieces, these will of course just simulate independently. Take for instance a car mesh: usually the chasis is one piece, the wheels are independent pieces, the windows, the doors, etc. They will simulate as independent pieces.

For pants, the same might apply depending on how the mesh is modeled. Front and back faces might be modeled as separate pieces, then if you simulate them they will just separate and crumble into a triangle puddle. It usually only makes sense to simulate meshes that are composed of a single piece, meaning you can follow a path from any vertex in the mesh to all other vertices. That's why if you take any random mesh you find online (that hasn't been modeled with cloth simulation in mind) and simulate it, results often won't be what you expect.

Note this applies to literally all existing cloth simulators, both realtime and offline. It's just how 3D meshes work. You can test these by simulating them in Blender, Maya, or any other modeling program that also lets you simulate cloth. Unity's built-in cloth simulator too.

Edit: if you need to simulate an arbitrary, potentially non-manifold mesh, you can use proxies to transfer simulation from a proper cloth sim-ready mesh to it. This is an advanced topic though. See: https://www.youtube.com/watch?list=PLnCR...e=emb_logo

[Notreturn]

Wow! ^^ Great and fast explanation.
Lastly; Lets think i want to download objects from scatchfab or anywhere else. Can i know it is a one piece of mesh or multiply on their sites? Or will i try them in blender type of softwares everytime?
Thanks again.

[josemendez]

Can i know it is a one piece of mesh or multiply on their sites?

There's no way to know that without inspecting the mesh (or getting the author to explicitly tell you it's one piece). Meshes must be made with their specific purpose in mind: if a mesh needs to get simulated, you need to take that into account when modeling it.

Oftentimes, meshes that look like they're one piece actually are not. If you import them in Blender or other software, go to face select mode, and move some faces around, they'll detach from the rest of the mesh right away even though they looked legit. This is because they don't share vertices with their neighboring faces.

On addition to this, many meshes are non-manifold (thus not supported by Obi Cloth, and many other physics simulators). This is a topological property that in short, means the mesh surface can't exist as a real object. This is a huge no-no for a lot of practical purposes: physics, certain rendering algorithms, 3d printing, etc. Here's a link that explains it better than I can:
https://sinestesia.co/blog/tutorials/non...-fix-them/

[Notreturn]

Hello Again.
I hope this is gonna be the last one ^^
I have progressed so much with your help.
But when i try to use 2 objects with one solver unity crashes.
I mean. When one solver and 2 objects children of this solver and if these 2 objects are active at the same time and once press Play button unity crashes.
I havent changed anything in the solver values. Just the Substeps is 5.