Normal vectors computation
This function calculates the normal vectors of all the triangles which belong to the boundary of the α-shape.
surfaceNormals(x, indexAlpha = 1, display = FALSE, col = 3, scale = 1, ...)
x |
An object of class |
indexAlpha |
A single value or vector with the indexes of
|
display |
Logical, if TRUE, |
col |
Color of the normal vectors. |
scale |
Scale parameter to control the length of the surface normals, only affect display. |
... |
Material properties. See |
The function surfaceNormals computes the normal vectors of all the
triangles which belong to the boundary of the α-shape for each
value of α in x$alpha[indexAlpha]. The magnitude of each
vector is equal to the area of its associated triangle.
If indexAlpha="all" or indexAlpha="ALL" then the function
computes the normal vectors for all values of α in
as3d$alpha.
If indexAlpha is a single value then the function returns an
object of class "normals" with the following components:
normals |
Three-column matrix with the euclidean coordinates of the normal vectors. |
centers |
Three-column matrix with the euclidean coordinates of the centers of the triangles that form the α-shape. |
Otherwise surfaceNormals returns a list of class
"normals-List" (each object in the list as described above).
x <- rtorus(1000, 0.5, 1) alpha <- 0.25 ashape3d.obj <- ashape3d(x, alpha = alpha) surfaceNormals(ashape3d.obj, display = TRUE)
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