[R] color scale in rgl plots

[David Farrelly]

Hello,

I'm trying to make a 3d plot using rgl in which the size and color of
each point corresponds to certain attributes of each data point. The color
attribute, let's call it X, is scaled to go from 0 to 1. The
rainbow(64,start=0.7,end=0.1) palette is perfect for what I want but I
don't know how to take that palette and pick a color from it based on
the value of X for a given data point. I'm fairly new to R and any
suggestions would be greatly appreciated.

Here's what I do - it's how to do the color mapping that has me stumped.

plot3d(th1,ph,th2,type='s',size=wd1,col=????(rp1,0,0,1),cex=2,ylab=NULL,xlab=NULL,zlab=NULL,xlim=c(0,1),ylim=c(0,2),zlim=c(0,1),box=TRUE,axes=FALSE)

I have also tried the more obvious col = rgb(a,b,c,d) where a,b,c,d are
functions of X but I can't manage to come up with a nice looking color
scale.

Thanks in advance,

David