Mesh+ workaround for m+Rings

I need the functionality of the m+Rings component of the Mesh+ plugin.

The goal is to extract the following lines (green) out of the attached mesh:

mesh.3dm (167.6 KB)

This can be achieved using the m+Rings component of Mesh+. However this plugin currently only works in Windows. Any other ideas how this can be achieved? Or to formulate the sub-question: How can one retrieve the topological distance of one vertex to another?

@DavidMans any ideas?


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It looks like WarpWeft could work there. You could then join them and sort the warp curves by where they meet one of the weft curves if you need them ordered.

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good point , that’s what I tried at first. But it does not seem to work here:

ah yes, I see those triangle fans make it impossible. It works for the rest

Also - Isn’t all of Mesh+ user objects? I’m curious why it doesn’t run on Mac.
(edit - I think I figured out why - it looks like many of the M+ objects contain VB scripts, which have a few issues on Mac as mentioned here. Converting them to C# would probably avoid these problems. There are some automated converters like this which will do the bulk of the conversion, though they usually need a bit of manual fixing too for stuff like case-sensitivity)

Awesome, that’s a great workaround! Thank you

The debug message usually shows the following:

Error (BC30451): 'ubound' is not declared. It may be inaccessible due to its protection level. (line 107)

Tried the converter, but it gives me a ton of errors, when pasting the Mesh+ code there… error messages I don’t understand currently tbh. But thank you for the suggestion!

Hey Rudi,
Really late replying to this…
Here is a c# implementation.
M+3 (whenever it gets finished) will be a single gha library and should be mac compatible. (8.4 KB)

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Hey @DavidMans, thank you very much for your C# implementation, and sorry for my late reply! Any news on M+3? There are some amazing functionalities in M+3, that I would love to be able to use on Rhino macOS!

Cheers, Rudi

Its getting close. Im down to 10 components then bug testing. Hope to release a buggy alpha very soon.


Awesome! Much success for the remaining components then, looking forward!


Is Mesh + 3 Available already? I couldnt find it in the usual places.
For some reason the C# script did not work for me.
The process would take forever or crash Grasshopper completely.
I used ChatGPT to rewrite it slightly and now it works.
This is the code that works for me on an M1Pro Mac:

using System;
using System.Collections.Generic;
using Rhino;
using Rhino.Geometry;
using Grasshopper;
using Grasshopper.Kernel;

public class Script_Instance : GH_ScriptInstance
    private void RunScript(
	Mesh mesh,
	IList<int> indexList,
	bool useNakedVertices,
	ref object A)
        // Check if the mesh is not null
        if (mesh == null)

        // Weld the mesh
        mesh.Weld(Math.PI); // Adjust the welding threshold as needed

        // Initialize the array for vertex distances
        int[] vertexDistances = new int[mesh.Vertices.Count];
        for (int i = 0; i < vertexDistances.Length; i++)
            vertexDistances[i] = -1;

        // Check if there are specified indices or if naked vertices should be used
        if (indexList.Count > 0 || (mesh.GetNakedEdges() != null && useNakedVertices))
            var topologyVertices = mesh.TopologyVertices;
            var processedVertices = new bool[mesh.Vertices.Count];

            // Get naked edge point status if needed
            if (useNakedVertices)
                processedVertices = mesh.GetNakedEdgePointStatus();

            // Precompute topology vertex indices
            var topologyVertexIndices = new int[mesh.Vertices.Count];
            for (int i = 0; i < mesh.Vertices.Count; i++)
                topologyVertexIndices[i] = topologyVertices.TopologyVertexIndex(i);

            // Process specified indices in indexList
            if (indexList.Count > 0)
                foreach (int i in indexList)
                    foreach (int vertexIndex in topologyVertices.MeshVertexIndices(topologyVertexIndices[i]))
                        processedVertices[vertexIndex] = true;

            // Set of initial vertices to process
            var initialVertices = new HashSet<int>();
            for (int i = 0; i < processedVertices.Length; i++)
                if (processedVertices[i])
                    vertexDistances[i] = 0;

            // Variables for loop
            var nextVertices = new HashSet<int>();
            int currentDistance = 0;
            int processedCount = initialVertices.Count;

            // Loop to calculate distances
            while (processedCount < mesh.Vertices.Count)
                var currentVertices = currentDistance == 0 ? initialVertices : nextVertices;
                nextVertices = new HashSet<int>();

                foreach (int vertex in currentVertices)
                    foreach (int connectedVertex in topologyVertices.ConnectedTopologyVertices(topologyVertexIndices[vertex]))
                        foreach (int meshVertexIndex in topologyVertices.MeshVertexIndices(connectedVertex))
                            if (!processedVertices[meshVertexIndex])
                                processedVertices[meshVertexIndex] = true;
                                vertexDistances[meshVertexIndex] = currentDistance + 1;

                if (processedCount >= mesh.Vertices.Count)


        A = vertexDistances;

    // <Custom additional code> 

    // </Custom additional code> 

Mesh+ 3 is nearly finished after a year-long complete refactor, but it is still at least a month out.
I just updated version 2 to fix the .net core issues with vb and a new download is available on food4rhino.


Omg! Thank you very much! Big news!

This is so awesome to hear. Thank you so much. I have used your tools for a while now and absolutely love them.
Looking forward to trying mesh+3