Btw, C4D support confirmed it as bug.

Your example used rectangular shapes. The example I sent don't have rectangular edges. If you like to disprove, please use the same data. I know that the connect function only works in a certain range. Even considering C4D's frame delay difficulties, the mesh I sent is always connected. Add a smooth modifier and it will be always smooth. Any brakes in the mesh would lead to glitches in the smoothing (or just phong). So this is an welding bug that appears when using cloth (or maybe other features). Even Scene Nodes Like "Extrude" do not work correctly. The last reliable function was using "Py-ParametricTools". I guess that was back in 2016.

Thanks for the examples. I've informed the tech support as you suggested. Let's see if they have a solution.
When looking at the point IDs, there are sometimes two IDs overlapping each or IDs appear where there are no points. When baking the mesh with this wrong IDs, it seems all welded fine. It looks like a bug that screws up the underlying topology and although it's not visible at the first glance, it confuses the cloth sim.

Thank you for your suggestion. I am looking for a none destructive, procedural solution as the face and the loft will change in future. In the original scene, the actual Moves by Maxon face mesh is used and will be replaced with further face captures. I just baked it to simply the scene. Also, the design of the loft extrusion needs to remain procedural during the creative process to test the behavior of different loft shapes along with the cloth simulating. Thus, the procedural welding is crucial.

I have tested the welding intensively by adding a Smooth Deformer and Subdivision Surface to the procedurally welded mesh. If points would not be welded or wrongly welded, it would cause already visible glitches, holes or or hard edges. So it seems the problem is somewhere else...

Thank you for the prompt reply.
Had a look at your scenes and both bypasses the essential part: procedurally connecting two (deformed/animated) meshes at their edge points who fit seamless together and add additional effects to it like cloth simulations. This approach preserve a valuable flexibility during the creation process and I am wondering if C4D is capable of that. While the points/UVs remain consistent, it seems the "Mesh-Chaos" is caused by hidden inconsistent mesh interpretations. Would be incredible useful to find a solution for that.

sample scene download link: https://www.dropbox.com/scl/fi/n4ek69jut3s95gozt1ro2/Cloth-glitch-on-procedural-mesh-01.zip?rlkey=dadewn8jts9zydrteb4364j3o&dl=0

Hi, I am trying to apply cloth to a procedural mesh. The mesh merges a face mesh from "Moves by Maxon" with a Loft. In order to let the loft's edge points have the same position as the face's edge points for a exact weld, I used a edge cloner or the "edge to spline" plugin. The points are welding correctly (a subdivision object or smoothing creates a smooth even mesh).

When applying a cloth tag, the mesh shows constant glitches. It seems like the mesh topology would constantly change. Maybe the procedural edge points causing a problem, although if it's point ID's would change, the loft and and welding would change too (not only the cloth simulation). I tried many approaches (using morph, scene nodes, etc.) Nothing works. Thanks for any suggestions!

I am also trying to attach a sample scene but the website states an error.
[Cloth glitch on procedural mesh 01.zip]error

Thank you for your prompt reply!
The pattern selection tool as well as the cv parametric selection tag would be extremely useful but they are restricted to polygon selections. I am aiming for edge selections, similar to a wireframe that only shows the horizontal rows of a cylindrical mesh. The mesh itself has to stay parametrically as it will deform/alter in several ways but keeps it's topology. Enhances scene example: https://www.dropbox.com/scl/fi/m8dcl0a7wy10t54urc15g/ring-loop-selections.c4d?rlkey=5gpk4puim2o7rbnp7f1ouy254&dl=0
Thinking of creating a straight cylinder with the same poly count as the loft nurbs. Then create a cloner with spline circles one for each polygon row. Make it edible and glue it to the cylinder with the surface modifier and attach the cylinder on the loft nurbs with a morph tag. A huge workaround and probably one part might not work or something has to become edible and the procedural creation workflow got lost...

Is there a way to select all vertical or horizontal edges of a mesh automatically? Similar to this plugin: https://www.youtube.com/watch?v=TnlXdttN8sE to to which newer C4D version are not compatible anymore.

Here is an example scene which is using ring/loop selection tools on a low poly mesh. But for higher resolution meshes, those tools seems insufficient, unless I missed a feature: https://www.dropbox.com/scl/fi/m8dcl0a7wy10t54urc15g/ring-loop-selections.c4d?rlkey=5gpk4puim2o7rbnp7f1ouy254&dl=0

Thank you!