I'm new to blender and having a lot of trouble simulating because of bad subdivisions (importing my objects from rhino as OBJs) TLDR: I want the subdivides on this to look like this so that it simulates properly
I'm planning to do a thick cloth simulation using mesh deform in a couple of days, and I've been practicing with simple geometries-- the problem is even these simple geometries seem to import horribly with their subdivisions, and when I go to simulate, the messy subdivisions create a mess.
I've inserted a couple images of the messy subdivides, and a gif showing an error of one simulation I did.
here are the messy subsurface divides from today
here are the messy sub divides from yesterday which are even worse
here is the thick mesh i'm simulating, which works perfectly
gif of the simulation error
But THIS type of subdivisioning is what I need! It's from a tutorial I was watching and I'm assuming he built the object in blender which explains the insanely beautiful clean subdivides.
I've tried cleaning up the subsurface through limited dissolve but that doesnt work because the simulation doesn't work on one face and if I try to add a subsurface modifier it becomes very messy again.  I basically just need an even square/ rectangular divide which currently is only possible for me to do if I make the original object on blender, which I won't be able to do soon once I need to use some more complex rhino models.
The subsurface divide modifier is just very confusing to me in general because it closes holes in my models, and generally doesn't seem to do what I want if it's not just a rectangle. I might just be confused on how it works though.
The subdivision surface modifier is optimized for meshes that are entirely (for the most part) constructed of quads. Your CAD imports have a lot of uneven topology and tris. This is inevitable when you are working in CAD programs with NURBS and then are forced to convert them to polygons so you can open in Blender (or other mesh based modeling tools). It's why you are getting ugly results with the subsurf modifier.
Here is how cloth simulation works &quot;under the hood&quot; (Straight from the blender docs):

As you can see from the above, accurate simulations depend on even topology so it can compute springs properly.
Unfortunately there is no magic button or export option that will fix your problem. Blender can't natively import NURBS - at some point in the pipeline you are converting from parametric data to polygons and horrible topology is inevitable.
The closest thing to an &quot;easy fix&quot; would be to import your model into ZBrush, and use ZRemesher.
Beyond that, your only other option is to remodel/retopologize the cloth you want to simulate using traditional subd modeling techniques.
Hope this helps.