# Using 'polygon' in a 3d plot

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## Using 'polygon' in a 3d plot

 I'm new to R, after many years of using Matlab. I've found the R function 'polygon' to be nearly equivalent to the Matlab function 'patch'. For example, the R commands: plot(c(0, 5), c(0, 4), type = 'n', asp = 1, ann = FALSE) x <- c(1, 2, 2, 1.5, 1) z <- c(1, 1, 2, 1.7, 2) polygon(x, z, col = 'green') produce a plot with a small green shape exactly as I expect. A nearly identical plot can be made in Matlab with these commands: x = [1, 2, 2, 1.5, 1]; z = [1, 1, 2, 1.7, 2]; patch(x, z, 'g') axis([0, 5, 0, 4]) box on In Matlab I am able to extend this quite easily to a three-dimensional plot by simply adding one more vector argument to 'patch'. I don't see how to do this in R using 'polygon'. (I've primarily looked at scatterplot3d.) Is there another function I can use? Since I expect that many of you do not use Matlab, I've put two graphics showing the example above (Plot 1) and a similar three-dimensional plot (Plot 2) on this page: http://staff.washington.edu/freeman/patch.html. It's Plot 2 that I'd like to be able to reproduce in R. Thanks for any advice!   -- Ted ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
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## Re: Using 'polygon' in a 3d plot

 Ted Freeman wrote: > I'm new to R, after many years of using Matlab. I've found the R > function 'polygon' to be nearly equivalent to the Matlab function > 'patch'. For example, the R commands: > > plot(c(0, 5), c(0, 4), type = 'n', asp = 1, ann = FALSE) > x <- c(1, 2, 2, 1.5, 1) > z <- c(1, 1, 2, 1.7, 2) > polygon(x, z, col = 'green') > > produce a plot with a small green shape exactly as I expect. A nearly > identical plot can be made in Matlab with these commands: > > x = [1, 2, 2, 1.5, 1]; > z = [1, 1, 2, 1.7, 2]; > patch(x, z, 'g') > axis([0, 5, 0, 4]) > box on > > In Matlab I am able to extend this quite easily to a three-dimensional > plot by simply adding one more vector argument to 'patch'. I don't see > how to do this in R using 'polygon'. (I've primarily looked at > scatterplot3d.) Is there another function I can use? > > Since I expect that many of you do not use Matlab, I've put two > graphics showing the example above (Plot 1) and a similar > three-dimensional plot (Plot 2) on this page: > http://staff.washington.edu/freeman/patch.html. Hi, I've got a plot3d() and polygon3d() function in the R.basic package (http://www.braju.com/R/).  Example: library(R.basic)  # plot3d() and polygon3d() xb <- c(0, 4, 4, 0, 0) yb <- c(0, 3, 3, 0, 0) zb <- c(0, 0, 4, 4, 0) plot3d(xb,yb,zb, type="l", theta=35, phi=30) x <- c(0.8, 1.6, 1.6, 1.2, 0.8) y <- c(0.6, 1.2, 1.2, 0.9, 0.6) z <- c(1, 1, 2, 1.7, 2) polygon3d(x,y,z, col="green") This gives a similar plot to what Matlab creates. /Henrik > It's Plot 2 that I'd like to be able to reproduce in R. > > Thanks for any advice! > >   -- Ted > > ______________________________________________ > [hidden email] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html> > ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
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## Re: Using 'polygon' in a 3d plot

 In reply to this post by Ted Freeman On 1/4/2006 4:20 PM, Ted Freeman wrote: > I'm new to R, after many years of using Matlab. I've found the R > function 'polygon' to be nearly equivalent to the Matlab function > 'patch'. For example, the R commands: > > plot(c(0, 5), c(0, 4), type = 'n', asp = 1, ann = FALSE) > x <- c(1, 2, 2, 1.5, 1) > z <- c(1, 1, 2, 1.7, 2) > polygon(x, z, col = 'green') > > produce a plot with a small green shape exactly as I expect. A nearly > identical plot can be made in Matlab with these commands: > > x = [1, 2, 2, 1.5, 1]; > z = [1, 1, 2, 1.7, 2]; > patch(x, z, 'g') > axis([0, 5, 0, 4]) > box on > > In Matlab I am able to extend this quite easily to a three-dimensional > plot by simply adding one more vector argument to 'patch'. I don't see > how to do this in R using 'polygon'. (I've primarily looked at > scatterplot3d.) Is there another function I can use? > > Since I expect that many of you do not use Matlab, I've put two > graphics showing the example above (Plot 1) and a similar > three-dimensional plot (Plot 2) on this page: > http://staff.washington.edu/freeman/patch.html. > > It's Plot 2 that I'd like to be able to reproduce in R. scatterplot3d returns xyz.convert, a function that can project 3d coordinates down to 2d for doing this sort of thing: xb <- c(0, 4, 4, 0, 0) yb <- c(0, 3, 3, 0, 0) zb <- c(0, 0, 4, 4, 0) s <- scatterplot3d(xb,yb,zb, type='l') x = c(0.8, 1.6, 1.6, 1.2, 0.8) y = c(0.6, 1.2, 1.2, 0.9, 0.6) z = c(1, 1, 2, 1.7, 2) polygon(s\$xyz.convert(x,y,z),col="green") You have to be careful about hidden lines; things drawn later obscure things drawn earlier, even if they should really be behind.  But in this case that doesn't matter, because the polygon doesn't need to be behind anything. Another possibility is to use the rgl package, but it doesn't have the high level plot functions, so the axes are harder to draw. Duncan Murdoch ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
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