triangles: Triangle Mesh Functions

Description

Functions to create and modify triangle mesh objects representing 3D surfaces..

Usage

makeTriangles(v1, v2, v3, color = "red", color2 = NA, alpha = 1,
              fill = TRUE, col.mesh = if (fill) NA else color,
              smooth = 0, material = "default")
updateTriangles(triangles, color, color2, alpha, fill, col.mesh,
                material, smooth)
translateTriangles(triangles, x = 0, y = 0, z = 0)
scaleTriangles(triangles, x = 1, y = x, z = x)
transformTriangles(triangles, R)

Arguments

v1,v2,v3

specification of triangle coordinates. If all three are provided then they should be matrices with three columns representing coordinates of the first, second, and third vertices of the triangles. If only v1 and v2 are provided then v1 should be a numeric matrix with three rows specifying coordinates of vertices, and v2 should be an integer matrix with three rows specifying the indexes of the vertices in the triangles. If only v1 is provided then it should be a matrix with three columns and number of rows divisible by three specifying the vertices of the triangles in groups of three.

triangles

triangle mesh object.

x,y,z

numeric of length one. Amounts by which to translate or scale corresponding coordinates.

color

color to use for the surface. Can also be a function of three arguments. This is called with three arguments, the coordinates of the midpoints of the triangles making up the surface. The function should return a vector of colors to use for the triangles.

color2

opposite face color.

alpha

alpha channel level, a number between 0 and 1.

fill

logical; if TRUE, drawing should use filled surfaces; otherwise a wire frame should be drawn.

col.mesh

color to use for the wire frame.

smooth

integer or logical specifying Phong shading level for "standard" and "grid" engines or whether or not to use shading for the "rgl" engine.

material

material specification; currently only used by "standard" and "grid" engines. Currently possible values are the character strings "dull", "shiny", "metal", and "default".

4 by 4 homogeneous coordinate transformation matrix to apply.

Value

A triangle mesh object of class Triangles3D.

Details

makeTriangles creates a triangle mesh object. updateTriangles modifies fields of such an object. Both may perform some consistency checks.

translateTriangles and scaleTriangles translate or scale the vertex locations of triangle mesh objects by specified amounts.

transformTriangles applies a transformation specified by a 4 by 4 homogeneous transformation matrix.