# [R] 3D or 4D plot

Duncan Murdoch murdoch at stats.uwo.ca
Fri Feb 20 20:28:43 CET 2009

```On 2/20/2009 1:55 PM, Duncan Murdoch wrote:
> On 2/20/2009 1:46 PM, kapo coulibaly wrote:
>> Ideally I would want it to look like a rubik cube with each little cube
>> color coded based on the fourth column (data column). Your suggestion might
>> work if I could color code based on data in the fourth column.
>> Thanks
>
> There's no primitive "cube" symbol in rgl, but you can get an array of
> colour-coded spheres:
>
> x <- rep(1:3, each=9)
> y <- rep(rep(1:3, each=3), 3)
> z <- rep(1:3, 9)
> colours <- terrain.colors(27)
> plot3d(x,y,z,col=colours, type="s", size=10)
>
> If you really want cubes, you can put them together (start with cube3d()
> to get one, and build on that), but it's a lot of work.

But it's Friday, so fun things like that are worth doing.  Here's some
code to draw a bunch of cubes with a variety of colours.  Elaborate on
it if you like.

Duncan Murdoch

cubes3d <- function(x,y,z,col="red",size=0.9,plot=TRUE) {

xyz <- xyz.coords(x, y, z, recycle = TRUE)
x <- xyz\$x
y <- xyz\$y
z <- xyz\$z

col <- rep(col, len=length(x))
size <- rep(size/2, len=length(x))

result <- list(vb=matrix(0, 4, 0), ib=matrix(1L, 4, 0),
material=list(color=NULL, normals=NULL))
class(result) <- "qmesh3d"

for (i in seq_along(x)) {
cube <- translate3d(scale3d(cube3d(), size[i], size[i],
size[i]), x[i], y[i], z[i])
offset <- ncol(result\$vb)
result\$vb <- cbind(result\$vb, cube\$vb)
result\$ib <- cbind(result\$ib, cube\$ib + offset)
result\$material\$color <- c(result\$material\$color, rep(col[i],
4*ncol(cube\$ib)))
}
if (plot)