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Is there a way to increase a 3D surface plot thickness like the plots here using the persp3D() function in the plot3D package in R? Can't seem to find anything in the documentation.

Werner Hertzog
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user2566907
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2 Answers2

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I was able to get this to work by creating multiple surfaces and connecting them using the curtain argument of the plot3D function. The thickness was controlled by the z argument of each surface. In case anyone needs the sample code, here it is;

For simplicity, I used meters to specify thicknesses/height of the surfaces

library(plot3D)
library(plot3Drgl)

# volcano data range
clim <- range(volcano)

# Surface 1
persp3D(z = volcano, zlim = c(0, 600), clim = clim, 
        box = FALSE, plot = FALSE, curtain = TRUE, border = "black")

# Surface 2 - 20m below surface 1
persp3D(z = volcano - 20, clim = clim, colvar = volcano, 
        add = TRUE, colkey = FALSE, plot = FALSE, curtain = TRUE, border = "black")

# Surface 3 - 40m below surface 1
persp3D(z = volcano - 40, clim = clim, colvar = volcano, 
        add = TRUE, colkey = FALSE, plot = FALSE, curtain = TRUE, border = "black")

# Surface 4 - 60m below surface 1
persp3D(z = volcano - 60, clim = clim, colvar = volcano, 
        add = TRUE, colkey = FALSE, plot = TRUE, curtain = TRUE, border = "black")

# Surface 5 - 80m below surface 1
persp3D(z = volcano - 80, clim = clim, colvar = volcano, 
        add = TRUE, colkey = FALSE, plot = TRUE, curtain = FALSE, border = "black")

# Open rgl for interactive viewing
plotrgl()

enter image description here

user2554330
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user2566907
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I don't know about plot3D, but rgl doesn't have a specific function for that. The way to do it is to calculate the polygons corresponding to the edges of the slab, and use polygon3d to plot those. For example:

data(volcano)
persp3d(volcano, col = "green")

# The bottom of the slab
persp3d(volcano-10, col = "blue", add = TRUE)

minx <- 0
maxx <- 1
miny <- 0
maxy <- 1

m <- nrow(volcano)
n <- ncol(volcano)

# The front edge
edgex <- c(seq(minx, maxx, length.out = m),
           seq(maxx, minx, length.out = m))
edgey <- miny
edgez <- c(volcano[,1],rev(volcano[,1] - 10))
polygon3d(cbind(edgex, edgey, edgez), coords = c(1,3), 
          col = "yellow")

# The back edge
edgey <- maxy
edgez <- c(volcano[,n],rev(volcano[,n] - 10))
polygon3d(cbind(edgex, edgey, edgez), coords = c(1,3), col = "white")

edgex <- minx
edgey <- c(seq(miny, maxy, length.out = n),
           seq(maxy, miny, length.out = n))
edgez <- c(volcano[1,],rev(volcano[1,] - 10))
polygon3d(cbind(edgex, edgey, edgez), coords = c(2,3), col = "black")

edgex <- maxx
edgez <- c(volcano[m,],rev(volcano[m,] - 10))
polygon3d(cbind(edgex, edgey, edgez), coords = c(2,3), col = "green")
user2554330
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  • Thanks for the response, @user2554330. I encountered the following error `Error in processOutside(i) : Cannot triangulate polygon` when I ran `polygon3d(cbind(edgex, edgey, edgez), coords = c(2,3), col = "black")` and `polygon3d(cbind(edgex, edgey, edgez), coords = c(1,3), col = "yellow")`. I have tried to fix the code but to no avail. – user2566907 Mar 29 '18 at 00:44
  • Yes, the algorithm for triangulation can fail. Generally if you try again it will work, as it normally has a random component. However, if the polygon is set up incorrectly it might never succeed, so it's worth checking your edge vectors, e.g. by calling `plot(edgex, edgez, type="l")` if you're having trouble. – user2554330 Mar 29 '18 at 10:23
  • Thank you very much @user2554330. I'll play around with the vectors. – user2566907 Mar 29 '18 at 22:35