The Vertex Weld modifier behaves like the Weld feature in editable poly and similar objects by combining all vertices within a specified distance from each other into a single vertex. Vertex Weld is useful for cleaning up meshes that contain clusters of vertices within small areas.
The results of using different Vertex Weld threshold settings
The new vertex is automatically placed at the average position of the combined vertices. Because the original vertices are removed, some associated faces and edges are usually removed as well. Also, welded vertices need not belong to the same element, so welding can result in combining elements within an object.
Example: To apply the Vertex Weld modifier to a mesh:
By deleting the polygon, you create an open mesh.
The reflection of the box shares a common seam but the vertices along the seam are not welded.
The distance, in scene units, within which vertices are automatically combined. Vertices farther apart than this value are not welded. Default=0.1
A threshold setting of 5.5 removes all detail, making the model unrecognizable.