Subdivide a 3D Object

Subdivides a shape3d object or a list of shape3d objects into objects of the same shape along a given dimension according to the proportions or frequencies specified in vector(s).

Usage

split3d(obj, ...)

# S3 method for class 'shape3d'
split3d(obj, p, dim, space = 0.1, ...)

# S3 method for class 'list'
split3d(obj, p, dim, space = 0.1, ...)

range3d(obj)

center3d(obj)

Arguments

obj

A shape3d object, or a list composed of them

...

Other arguments for split3d methods

p

For a single shade3d object, a vector of proportions (or a vector of non-negative numbers which will be normed to proportions) indicating the number of subdivisions and their scaling along dimension dim. For a list of shade3d objects, a matrix whose columns indicate the subdivisions of each object.

dim

The dimension along which the object is to be subdivided. Either an integer: 1, 2, or 3, or a character: "x", "y", or "z".

space

The total space used to separate the copies of the object along dimension dim. The unit inter-object space is therefore space/(length(p)-1).

Value

split3d returns a list of shape3d objects.

range3d returns a 2 x 3 matrix, whose first row contains the minima on dimensions x, y, z, and whose second row contains the maxima.

center3d returns a numeric vector containing the means of the minima and maxima on dimensions x, y, z.

Details

split3d is the basic workhorse used in mosaic3d, but may be useful in other contexts.

range3d and center3d are utility functions, also useful in other contexts.

The resulting list of shape3d objects is actually composed of copies of the input object(s), scaled according to the proportions in p and then translated to make their range along the splitting dimension equal to that of the input object(s).

See also

mosaic3d

shapelist3d for the plotting of lists of shape3d objects.

Author

Duncan Murdoch, with refinements by Michael Friendly

Examples

if (require(rgl)) {
  open3d()
  cube <- cube3d(alpha=0.4)
  sl1 <- split3d(cube, c(.2, .3, .5), 1)
  col <- c("#FF000080", "#E5E5E580", "#0000FF80")
  shapelist3d(sl1, col=col)

  open3d()
  p <- matrix(c(.6, .4, .5, .5, .2, .8), nrow=2)
  sl2 <- split3d(sl1, p, 2)
  shapelist3d(sl2, col=col)
  }
#> Loading required package: rgl
#> Warning: package 'rgl' was built under R version 4.5.2