Skinning: Tangency between existing and new faces
Technical Area: Surfacing
The Skin functionality allows users to generate a surface by interpolating a set of parameter curves making up a mesh. Another use for Skin is for healing: it can repair by bridging possible gaps between non-adjacent surface parts. Users can also make a smooth, tangential connection to existing geometry, providing this does not contradict the curve definitions.
Making these smooth connections really tangential requires knowledge of applying the Skin functionality. This article describes how users can make perfect tangential connections by using data from existing objects.
The following example shows a specialty that needs to be known when tangent connections between new skinned faces and existing faces are required.
The mesh below is created manually and the right edge is gathered from the neighbor face.
A new face is skinned over the mesh.
When we now analyze the connection between the newly skinned and the existing face by using the surface analysis with zebra stripes, we can see that tangency is not given between those two faces.
In this example, the new face is skinned over the reduced mesh. The edge of the neighboring face is used to close the mesh.
It is the same edge as in the first example but now it is part of the boundary of the neighboring face.
When we analyze the connection between the faces again by using the surface analysis with zebra stripes, we can see that tangency is now given.
The reason being that in the second example the tangential field of the neighboring face could be considered by the skin algorithm. This tangential field was not available in the first example.
It is important to consider this fact when skinning a new face.