Hello, In Grasshopper I am trying to get the vertex normals of a mesh. The issue is that, as shown by the planes, the direction of these normals seem off. What is causing this? It is worth noting that it is a closed mesh with welded seams. James [tetrahedron_problem1] [tetrahedron_problem2]

The normals on a welded tetrahedron are not consistent. A similar problem can be seen on a simple mesh box. [image] [image] mesh-normals-issue.gh (21.4 KB)

Thanks for pointing this out this issue, Martin. If I wanted correct vertex normals all across my mesh, would you recommend getting an average of the normals of the surrounding faces of the vertex? If so, is this achievable with components? I do not know code. James

“By hook or by crook”. I feel like I mostly stumbled my way through this one. Not made to work on multiple meshes. Maybe @inno or @martinsiegrist has a better idea: [Screenshot 2026-03-13 035429] [high res test] Vertex Normals Not Properly Oriented to Welded Mesh VR 01.gh (15.1 KB)

Hello I think there is a bug in Weld Mesh, normals are not recomputed. @dale , @DavidRutten Using Unify Normal updated the normals [image] [image] Or welding with other tools, WeldMesh from Ngon works Weld Mesh from Nautilus works (old and new version) Combine&Clean from Kangaroo works Join&…

Nice Topology reconstruction. Mesh Topology from SandBox gave the same things [image] BUT Rhino/Grasshopper work IF Normals are recomputed, for some reason after weld mesh normals are not or strangely recomputed.

A mesh, in its simplest form, is just a set of vertices and faces that records which vertices belong to which faces, but nothing more about higher‑level topology. A normal is typically a unit vector orthogonal to a planar geometric element, such as a mesh face. Individual mesh vertices do not inhe…

I had never noticed this issue before, thank you for pointing it out. @Volker_Rakow Thank you for the idea. I tried to take it a step further to make it work with data trees as well. Let me know if it works. [image] mesh vertex normals.gh (18.5 KB) This was done without any plugins or coding. …

[image] Reorder planes of a irregular mesh Grasshopper To get the faces connected to a vertex, you can use this function https://developer.rhino3d.com/api/RhinoCommon/html/M_Rhino_Geometry_Collections_MeshVertexList_GetVertexFaces.htm like this: vertexfaces.…

Vertex Normals Not Properly Oriented to Welded Mesh

Grasshopper

Volker_Rakow (Volker Rakow) March 13, 2026, 2:55am 4

“By hook or by crook”. I feel like I mostly stumbled my way through this one. Not made to work on multiple meshes. Maybe @inno or @martinsiegrist has a better idea:

Vertex Normals Not Properly Oriented to Welded Mesh VR 01.gh (15.1 KB)

Select Mesh Faces from Curve

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Vertex Normals Not Properly Oriented to Welded Mesh

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