Fragment Patch Control Point Problem

Hello World,

I have the following problem: I have a mesh that I want to close. I thought the best idea was using the Fragment Patch, convert the patch surfaces into meshes, and eventually combine them with the original mesh.

However, not all of the naked edges could be closed (remaining naked edges in green). After a little investigation of the problem I found out that the patches don’t have the same amount of control points (pink) as the naked edges (red) have. This is however obviously required for welding them.

Does anyone have an idea to solve this? Any help or advice is appreciated.
Thanks, Henry

Note: The Boundary Surfaces wouldn’t do here, since the naked edges are not planar.

Hello, that’s actually not your problem. You simply have worked so unclean, that you create conditions impossible to work with further. Without a file there is no chance of help, although I see little chance even with a file.
Actually its a bad idea to use patch, even worse trying to patch a polyline boundary with it and as you said, even with usable patch results you wont match neighbouring vertices. You have to decide, working with meshes or with surfaces, but you shouldn’t mix up both. A possible solution to your problem: do a triangulation of your boundary vertices. I have no idea how to do this in your case, it depends, but its definitely not an easy task.

What do you mean by that?

Maybe I misdescribed my problem. The naked edges I want to close are not the green ones in the image in my first posting. The following image should make clear which holes I really want to close. This is how the mesh looks in the first place (and it is definitely clean):

no, you did not.
the mesh internally might be clean (at least as far as it can be), but your outlines are definitely not, which indicates that your design is not working well (…which doesn’t mean its bad).

How will you close a hole, when its boundary doesn’t let you do this properly.This is what I mean by bad conditions. In theory you can create faces connecting the edge vertices (triangulation), but the closed facets will look bad.

I mean you are using weaverbird doing quick modelling, but being quick in first place means more work later on.
Wouldn’t it be better modelling the shape as a whole and cutting in holes in later on. This will ensure clean boundaries.
Another option, you could modify existing border vertices to form a planar boundary.

Is Weaverbird so badly engineered? o.O

no, its not the plugin, its the algorithm. Sub-d mesh modelling is primarily used for quick sketching/ form-finding or for very organic modelling (not free-form per se).

It creates new vertices in between exiting ones and averages its position with a certain ratio, so that it visually appears to be smooth. However its still a mesh, meaning it has no real curvature, its a connection of linear facets, which only appear to be smooth through shading. If you turn on “Flachschattierung”(flat shading) you will see how it really looks like.
This is fundamentally different to surfaces, where you have curvature mathematically described for every point on that shape. Now if you use surface tools, like patch, but you feed in meshes data, this obviously leads to problems, because surface algorithms usually cannot properly fit to a non-curved shape which is not planar.
I personally think sub-d is fun to use and you can do amazing things with it in very short time, but everywhere where precision is needed for instance in engineering, product design etc. you will need to overwork your sub-d models to surface models at some point of your process chain or at least you have to fight much harder problems later on.

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