Unable to dissolve faces of a subdivided mesh (e.g. cloth) after deforming it I let a cloth drape on an object using some physics simulation. Then I need to take the cloth, merge all the faces and make it into a single block and then subdivide it. However, it seems that dissolve does not execute fully for some reason and many of the faces on the cloth do not get merged. However, if I do the same thing for an undeformed cloth, I can merge all of the blocks on the cloth and get a non-divided cloth. I can show the issue via the images below:

This is the original, deformed cloth:



And this is after I select all vertices and then click on Limited Dissolve:



I wonder, how can I resolve this issue so that when I click on Limited Dissolve I'll get a non-divided cloth?
The limited dissolve will "reduce detail on planar faces and linear edges" - that is if you have a flat plane made up of 100 faces, limited dissolve will merge them into one face but if the plane is bent in the middle it will reduce it to two faces. For a mesh that has been deformed by the cloth simulation you will find almost every face is at an angle to the face next to it so limited dissolve is not likely to simplify the geometry very much.

If you want to reduce the geometry of your deformed mesh then you will want to try something like the decimate modifier or the remesh modifier that allows you to generate a similarly shaped mesh with less geometry.

From your comment it sounds like you want to use a simple mesh to quickly get a rough shape and then add more detail to be used in the simulation to get the final cloth shape that you want. To do this, start with a low res mesh, add the cloth sim and let it play through for a while, then apply the cloth modifier, subdivide and repeat. You could also model or sculpt a mesh close to the final shape that you want and then add a cloth sim to that.