How to improve ops limited dissolve?

Support Modeling
1

How to improve ops limited dissolve?

I have some holes in mesh,I try to clean some vertexes.

but some models got some extra vertex can’t be clean.

here is screenshot

7.PNG
7.PNG1326×1504 293 KB

how to improve that ?

testblend.blend (1.9 MB)

2

Merge by distance

3

thank you ,I’ll try.

4

If this is just an example then this is somekind of nightmare… if this is you model you me more happy to just rebuild this… Anyway: If selecting all walls by normals and dissolve individually you may get some better results… but they always are “not nice”… (may i ask where do you get that from?) :

nigtmare
nigtmare800×500 19.1 KB

5

hello, this is created by my own script using the three.js engine export gltf model.

6

Ups… then you may overthink you generating algorithm… or the export of three.js is just … bad… ???
Hmm just had an idea and used a boolean modifier: union with self aware (and node9) … this seems to solve some problems because dissolve is better now …and did a triangulate at last:

NOnigtmare
NOnigtmare800×600 45.1 KB

7

hi,your vertexes still not clean

8

Limited dissolve will only get you so far. My process is, merge by distance, then limited dissolve, (usually with an angle of 1 degree or less to keep things planar only). Then I’ll apply a direct cut through the mesh and manually tidy up edges.
Also, your geometry isn’t tidy, so you’re ending up with all sorts of issues even if you apply limited dissolve & merge by distance.

9

Maybe, But my global idea all these steps was auto-execute by python script, I can’t use manually tidy up edges.

10

In which case, you are definitely going to have issues. I have done a video of what I had to do to tidy up this mesh. Basically, most of it boils down to a couple of things. One, you have the window edges both in the main model and as separate items. Two, your “cuts” do NOT go all the way through the mesh, so 90% of the errors are due to points being not bisecting edges, as a result, there’s all sort of nastiness in the polygons. Once the video has encoded, I’ll put a link up here for you to see the issues.

EDIT: Video:
https://youtu.be/bk5r2SLSiro

11

I think you also have to take into consideration that polygons can’t have a hole in them in Blender. So you’re bound to have extra edges somewhere. It is either chosen at random or you can ensure its position by adding an extra loopcut along the Z axis where it intersects with all the holes. Like the youtube link in previous comment.

Also some softs like Sketchup don’t really make the user aware of the concept of N-Gons but they are definitely there under the hood, ingraining a false confidence that a mesh is “clean” but in reality it’s anything but. However I think it doesn’t matter that much unless you’re planning on animating it or displaying a wireframe view ?

12

Yes, the extra cuts are useful, but as I say, in the initial geo, pretty much all of them are not making it to a connecting edge, thus the mess. NGon wise, for building, I always use them, just makes sense. Providing you have those intersecting cuts, you’re good to go.

13

Yup I completely agree. Extra edges can be a pain in the butt sometimes, for example the Acad renderer has trouble sometimes with occluding edges even though the two connected faces are coplanar… So there a N-gon helps tremendously.

14

I know… The vertices came from your script… how to you produce them ? Why does the wall have multiple middle lines? Why are there multple non equal cuts in the windows?
Later you wrote:

?? You search a pyhton script to repair the mess from:

? :question: !