I would like to perform a cloth simulation by combining two or more different cloths

Question

Thank you for finding my question. I'm Japanese and I'm not good at English, so please allow me to post using Google Translate.

Production environment: macOS Sonoma Blender4.0

As the title suggests, I would like to create a cloth simulation by combining two or more different cloths (Command+J).

I made a blanket with frills. I finally solved this problem by sewing the ruffle onto the blanket, but I'm looking for other solutions. For example, you might want to give the texture of a different fabric to a ruffle or blanket, or add another fabric fabric embellishment, such as a ribbon. You may also want to add seam objects.

Combining them with Command + J to perform a cloth simulation will separate the objects. I would like to perform a cloth simulation where objects follow without separating. Is there any other way other than sutures?

Answer 1

If we use cloth on disconnected geometry, there won't be any forces created to hold the geo together:

We could connect the geometry (right) or use sewing lines (left):

But sewing lines won't create any bending forces and won't play nicely with some other modifiers. And connecting the geometry change your rendering geometry, in a way that is likely not going to be what you want for future subdivision:

There are some things we could probably do to help this, using GN to mask away some geometry between the physics and other modifiers. But the fool-proof method of dealing with needing one topology for physics and a different topology for rendering is to use two different meshes:

By surface or mesh deforming from a physics mesh to a rendering mesh, you can use a different topology for your cloth and your rendering mesh, tuning the topology to the needs of each. Your physics pillow can be a single mesh while your rendering object is two separate meshes.