Weld

Removes texture mapping coordinate information from each shared mesh vertex.

Steps:

  • Type the maximum angle between mesh polygon normals where welding of points should occur.

  • If two naked mesh edge points of a selected mesh are coincident, and their neighboring faces are within the angle tolerance of each other, they will be replaced by a single mesh point. If the two points are from different “sub-meshes” of a joined mesh, the meshes become one mesh that cannot explode.

To perform a similar operation with control points
, see the SetPt
command.

Welding polygon meshes affect rendering, texture mapping on mesh objects, and file export for stereolithography.

Smoother Rendering

In wireframe these two meshes look the same.

Rhinoceros weld 002 Weld

When shaded, the red mesh looks smooth and the blue mesh looks chunky.

Rhinoceros weld 001 Weld

Each triangle vertex in the red mesh is welded to its neighbors. This causes the vertices in the red mesh to look smooth. No points in the blue mesh are welded. This causes the vertices in the blue mesh to look sharp.

Suppose you want the blue mesh to look smoother.

First you have to determine the angle tolerance. The shaded creases of this angle should look sharp.

Texture Mapping

Texture mapping coordinates control how a texture wraps around the object. These are two-dimensional coordinates that are attached to a polygon vertex, and they determine which point on the texture bitmap maps to this vertex. The points between the vertices interpolate from the vertex values.

The bottom left corner of the bitmap is the origin, the bottom right is (1,0), top left is (0,1) and top right is (1,1). The texture mapping coordinates are always between these values.

Only one pair of texture mapping coordinates can attach to a single vertex. That is why if you weld vertices — and thus remove the overlapping duplicates — you throw away all but one pair of texture mapping coordinates.

The loss of texture mapping coordinates is irreversible. You cannot recover the mapping coordinates from the remaining mesh information.

To remove welding (and to also lose the texture mapping coordinates), use the UnWeld
or the UnWeldEdge
command.

STL Mesh Export Diagnostics

In some rapid prototyping machines, STL files must contain completely closed (watertight) polygon mesh objects.

You might want to use the Join
command, then Weld (angle=180), then UnifyMeshNormals
to turn a group of meshes into a single watertight mesh object, and use SelNakedMeshEdgePt
to find the open (naked) edges. Following this procedure will ensure that the meshes really do fit together before exporting them for use in an expensive STL job.

See Importing and exporting STL files
.

Notes

  • The Weld command will not merge vertices of two different meshes. They must be joined before welding is effective.

  • The Weld command does not report the results on the command line.

Rhinoceros weld Weld

Mesh Tools > Weld mesh

STL Tools > Weld Mesh Vertices

Welding > Weld mesh

Rhinoceros Menu2 Weld

Mesh > Mesh Edit Tools > Weld

Rhinoceros Gray Book Open Weld Related topics…

WeldEdge

Removes texture mapping coordinate information from each shared mesh vertex on a selected edge.

Steps:

  • Select a mesh edge.

Rhinoceros WeldEdge Weld

Welding > Weld Mesh Edge

Rhinoceros Menu2 Weld

None

Rhinoceros Gray Book Open Weld Related topics…

WeldVertices

Removes texture mapping coordinate information from each selected mesh vertex.

The WeldVertices command lets you select mesh vertices to weld, rather than the entire mesh. It does not, however, give you a tolerance angle between faces to weld, like the Weld
command does. You can window select by turning mesh points on and selecting the points prior to the command or you can run the command and then select multiple individual points.

Rhinoceros weldvertices 001 Weld

Rhinoceros weldvertices 002 Weld Rhinoceros weldvertices 003 Weld

Rhinoceros WeldVertices Weld

Welding > Weld Mesh Vertices

Rhinoceros Menu2 Weld

Mesh > Mesh Edit Tools > Weld Selected Vertices

Rhinoceros Gray Book Open Weld Related topics…

Unweld

Adds texture mapping coordinate information to each shared mesh vertex, which removes the smoothing effect in shaded views and renderings.

Rhinoceros UnWeld Weld

Mesh Tools > Unweld Mesh (Right click)

Welding > Unweld Mesh (Right click)

Rhinoceros Menu2 Weld

Mesh > Mesh Edit Tools > Unweld

Rhinoceros Gray Book Open Weld Related topics…

UnweldEdge

Adds texture mapping coordinate information to each shared mesh vertex on a selected edge.

Rhinoceros UnWeldEdge Weld

Welding > Unweld Mesh Edge (Right click)

Rhinoceros Menu2 Weld

Mesh > Mesh Edit Tools > Unweld Selected Edges

Rhinoceros Gray Book Open Weld Related topics…

 

Weld