isocubes (version 1.0.0)

gen_isosurface: Generate voxel coordinates defined by an implicit function

Description

Generate voxel coordinates defined by an implicit function

Usage

gen_isosurface(
  f,
  upper = 0,
  lower = -Inf,
  scale = 1,
  nx = 51,
  ny = nx,
  nz = nx
)

Value

data.frame of coordinates

Arguments

f

function of the form f(x, y, z) which returns a numeric value

lower, upper

When the supplied function is evaluated, the lower and upper limits define the range of values which will be considered to be inside the object. The efault [-Inf, 0] means that any value less than or equal to zero is inside, and all positive values are outside.

scale

extra scaling factor applied to coordinates before calling function

nx, ny, nz

the dimensions of the volume within which the function will be evaluated

Examples

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Create a sphere of radius 10
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
coords <- gen_isosurface(
  f = function(x, y, z) {x^2 + y^2 + z^2},
  upper = 10^2
) 

coords |>
  isocubesGrob() |> 
  grid::grid.draw()
  
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Create a complex shape
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
grid::grid.newpage()
f <- function(x, y, z) {
  (x-2)^2 * (x+2)^2 + 
  (y-2)^2 * (y+2)^2 + 
  (z-2)^2 * (z+2)^2 +
  3 * (x^2 * y^2 + x^2 * z^2 + y^2 * z^2) +
  6 * x * y * z -
  10 * (x^2 + y^2 + z^2) + 22
}

gen_isosurface(
  f = f,
  scale = 0.1,
  nx = 70
) |> 
  isocubesGrob(size = 2) |> 
  grid::grid.draw()