R help - Mar 2013 - different colors for two wireframe spheres

Dear List,

I have the code below adapted from the lattice-package examples to draw two
spheres. I would now like to give
both different surface colors, e.g. one red and one blue. 

 ## 3-D surface parametrized on a 2-D grid
					 
			 n <- 10
			
			 tx <- matrix(seq(-pi, pi, length.out = 2*n), 2*n, n)
			 ty <- matrix(seq(-pi, pi, length.out = n) / 2, 2*n, n, byrow = T)
			 xx <- cos(tx) * cos(ty)
			 yy <- sin(tx) * cos(ty)
			 zz <- sin(ty)
			 zzz <- zz
			 
			 bxx <- xx+5 
			 byy <- yy+5
			 bzzz <- zzz+5
			 
			 xx=rbind(xx,rep(NA,n),bxx)
			 yy=rbind(yy,rep(NA,n),byy)
			 zzz=rbind(zzz,rep(NA,n),bzzz)
			 gr<-rbind(matrix(1,n,2*n),rep(NA,n),matrix(2,n,2*n))
			
			 wireframe(zzz ~ xx + yy,
groups=gr,col.groups=c("red","blue"))

I tried various parameters as col.groups, col.regions but I have the impression
that the "groups" argument in the wireframe command can only be used
when supplying a data argument, which does not allow to plot the spheres as far
as I tried. Is there a solution for this?

Cheers

David Schellenberger

On Mar 5, 2013, at 3:28 AM, David Schellenberger Costa wrote:
> Dear List,
> 
> I have the code below adapted from the lattice-package examples to draw two
spheres. I would now like to give
> both different surface colors, e.g. one red and one blue. 
> 
> ## 3-D surface parametrized on a 2-D grid
> 					 
> 			 n <- 10
> 			
> 			 tx <- matrix(seq(-pi, pi, length.out = 2*n), 2*n, n)
> 			 ty <- matrix(seq(-pi, pi, length.out = n) / 2, 2*n, n, byrow = T)
> 			 xx <- cos(tx) * cos(ty)
> 			 yy <- sin(tx) * cos(ty)
> 			 zz <- sin(ty)
> 			 zzz <- zz
> 			 
> 			 bxx <- xx+5 
> 			 byy <- yy+5
> 			 bzzz <- zzz+5
> 			 
> 			 xx=rbind(xx,rep(NA,n),bxx)
> 			 yy=rbind(yy,rep(NA,n),byy)
> 			 zzz=rbind(zzz,rep(NA,n),bzzz)
> 			 gr<-rbind(matrix(1,n,2*n),rep(NA,n),matrix(2,n,2*n))
> 			
> 			 wireframe(zzz ~ xx + yy,
groups=gr,col.groups=c("red","blue"))
You might try:

    wireframe(zzz ~ xx + yy, groups=gr, drape=TRUE )

Notice that in help(wireframe): Details you find a sentence:

"Note that this feature does not work with groups, subscripts, subset, etc.
Conditioning variables are also not supported in this case."

 This sentence refers back to the paragraph beginning "For single panel
plots, wireframe can also plot parametrized 3-D surfaces..."  that
describes the method you are using to draw those spheres.
> 
> I tried various parameters as col.groups, col.regions but I have the
impression that the "groups" argument in the wireframe command can
only be used when supplying a data argument, which does not allow to plot the
spheres as far as I tried. Is there a solution for this?
> 
> Cheers
> 
> David Schellenberger
> ______________________________________________
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David Winsemius
Alameda, CA, USA