# Triremesh holes and outer mesh that they share same boundary

Dear friends,
I want to triremesh a split mesh that has two parts, and how can I make them use the same boundary vertices?
In the following picture, the boundary is not aligned and that means the two mesh can not be joined.

If the inner and outer shape come from splitting a surface with a curve, you can join them into a polysurface before input and preserve the feature curve while also matching vertices, as shown here

Hi Daniel, Thanks for your reply. But besides passing through, I want the triremeshed hole mesh boundary vertices the number as the curve(maybe could be turned into polyline) vertices. What should I do? Thanks again!!! For example, the curve or polyline has 6vertices and the triremeshed vertices should only have 6 vertices on the boundary and pass all and only these 6 vertices.

If that can be realized, the doundary vertices can be easily manipulated, then we can join different meshes easily and at will.

I think it might be easier to explain if you can post a file of what you are starting from.

If you have a planar surface or curves to start with, then you can use the polysurface approach described above to generate a starting mesh with vertices along the shared boundary, then preserve this as a feature curve.

If instead you have some existing meshes from a different source with adjacent boundaries but non-matching vertices then a different approach will be needed (like the one here).

generate and join mesh.gh (54.7 KB)
I generate two meshes by polylines and one mesh by adopting rhino surface. After triremeshing my wish is that their vertices are connected on the boundary but the output is not.

The simplest way is to join your surfaces into a polysurface. Then when it is meshed the vertices match up along the edges, and this is preserved in the remeshing:
remesh_curves.gh (43.4 KB)

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[facepalm] But how can I extract one of them for different use in later process?

remesh_curves_separate.gh (45.4 KB)

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That method is extremely neat and simple. I really appreciate your kind help!!!

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Hi, Daniel. I used this method quite well. But recently I find it is not always working that some small angled edges could be welded, so what to do with this, and is there an option for always keeping the hard edge?
Just like the picture showed, some edges were welded, could not be exploded for later operation.

Many thanks!

Can you share or send me the file (or just the problematic bit of it)?