R – Adding a legend to an rgl 3d plot

3dplotrrgl

I am trying to draw a 3d plot using rgl with colors legend indicating which color refer to which class (called 'cut.rank'):

plot3d(
data.focus$normalized.price_shipping,
data.focus$seller_feedback_score_rank,
data.focus$seller_positive_feedback_percent_rank, 
col=as.factor(data.focus$cut.rank), 
size=1, 
type='s',
xlab = 'Normalized Price',
ylab = 'Seller Feedbacl Score Rank',
zlab = 'Seller Positive Feedback Percent Rank',
main = 'Rank By Price, Feedback score and Positive Feedback Score',
sub = 'Search Rank has 3 colored levels',
colkey = list(length = 0.5, width = 0.5, cex.clab = 0.75))
) 

But I can't seem to get the legend showing up in the plot. (See attached plot)
Any idea ?enter image description here

Best Solution

I'm not sure the colkey option applies to the plot3d function. You can use legend3d instead to add a legend the way you would in normal 2d plots:

library(rgl)

#dummy data
set.seed(1)
x <- cumsum(rnorm(100))
y <- cumsum(rnorm(100))
z <- cumsum(rnorm(100))
cuts = cut(x = 1:length(x), breaks = 3)

# open 3d window
open3d()

# resize window
par3d(windowRect = c(100, 100, 612, 612))

# plot points
plot3d(x, y, z,
       col=rainbow(3)[cuts], 
       size = 2, type='s')

# add legend
legend3d("topright", legend = paste('Type', c('A', 'B', 'C')), pch = 16, col = rainbow(3), cex=1, inset=c(0.02))

# capture snapshot
snapshot3d(filename = '3dplot.png', fmt = 'png')

enter image description here

Update: colkey is an argument to scatter3D in the plot3D package (not the same as the plot3d function in the rgl package). You can use this as well:

library(plot3D)
scatter3D(x,y,z, col = rainbow(3)[cuts], colvar = NA, colkey = F, pch = 16)
legend("topright", paste('Type', c("A", "B", "C")), pch = 16, col = rainbow(3), cex=1, inset=c(0.02,0.2))

enter image description here