How do I prevent the cloth from going through the mesh as seen in the capture ?

it depends on whats causing the interpenetration, more info may be needed

but it feels pretty forced, so if it's caused by a collider or strong pin, then there is not much Vellum can do to prevent it, you just should be aware of not forcing it into such situations and maybe use different approach that gives Vellum a chance to converge

Posting a hip file would help, but you can tell from the jittering all along the bottom of your mesh that vellum is fighting against itself. That type of jittering is usually caused by settings that are "un-convergeable". For instance, if you set your bend and compression stiffness too high and then try to get a piece of cloth to fall to the floor in a heap, you may get that kind of jittering because the cloth wants to compress into a smaller space, but you've given it a high bend and compression stiffness that is preventing that from happening. The result is jitter.

If I had to guess, I'd say there is something wrong with your invisible collider that is causing both the jitter and the inter-penetration of the top of the cloth. But hard to tell from just a screen capture.

A higher stiffness along with a smaller multiplier around 0.1 doesn't cause the penetration. I may post a hip file after I adjust parameters more.

If the mesh isn't dense, what is the best parameter to get more wrinkles in cloth, I don't want too many but I want more in specific areas ?

Mesh resolution, bend stiffness, and compression stiffness are the main parameters that affect how cloth behaves. Stretch stiffness also makes a difference, but less so that the others for typical fabrics like cotton, denim, leather, etc. If you are trying to simulate stretchy fabric, of course, it's a different story.

More recent versions of vellum do a better job working independently of mesh resolution. A medium resolution mesh should behave "similarly" to high resolution meshes, but will lack finer detail and wrinkling. But mesh resolution will definitely create an upper limit on how detailed your wrinkles can get.

This is a good starting point for understanding how different settings affect the look of different types of fabric:

https://www.sidefx.com/tutorials/h17-vellum-cloth-lookdev-tips/ [www.sidefx.com]

made-by-geoff
Mesh resolution, bend stiffness, and compression stiffness are the main parameters that affect how cloth behaves. Stretch stiffness also makes a difference, but less so that the others for typical fabrics like cotton, denim, leather, etc. If you are trying to simulate stretchy fabric, of course, it's a different story.

More recent versions of vellum do a better job working independently of mesh resolution. A medium resolution mesh should behave "similarly" to high resolution meshes, but will lack finer detail and wrinkling. But mesh resolution will definitely create an upper limit on how detailed your wrinkles can get.

This is a good starting point for understanding how different settings affect the look of different types of fabric:

https://www.sidefx.com/tutorials/h17-vellum-cloth-lookdev-tips/ [www.sidefx.com]

Thanks, the link explains some of the parameters in short.