[R] adding points to a wireframe

[Jarrett Byrnes]

A quick question.  I'm trying to plot a surface from a fitted model  
along with the original points, as in the following example:


df<-data.frame(expand.grid(100*runif(1:100), 100*runif(1:100)))
df$Var3<-rnorm(length(df$Var1), mean=df$Var1*df$Var2, sd=10)

my.lm<-lm(Var3 ~ Var1*Var2, data=df)

my.fun<-function(x,y) predict(my.lm, data.frame(Var1=x, Var2=y),  
type="response")

df2<-data.frame(expand.grid(x=seq(1,100,10), y=seq(1,100,10)))
df2$z<-my.fun(df2$x, df2$y)

wireframe(z ~ x*y, data=df2, col="grey",
panel.3d.wireframe=function(x,y,z,...){
	panel.3dwire(x = x, y = y, z = z, ...)
	panel.3dscatter(x=df$Var1,
					y=df$Var2,
					z=df$Var2,
					...)
})

Which I coded according to what I saw here:
http://www.nabble.com/add-points-to-wireframe-td12901155.html
http://www.nabble.com/wireframe---add-data-points-td16984174.html

However, this plots the wireframe, then puts the error message:
Error using packet 1
'x' and 'units' must have length > 0

Any thoughts on what is incorrect here?

Thanks.