使用ggplot2和plotly绘制3D棱镜

Question

I have a list a with three matrices and a vector h with three heights (any positive real number). These matrices form triangles, that is, the base of the prism. I want to add the information of vector h to construct prisms.

I've created a function to plot graphics in 2D ( pplot ). How can I plot the prisms as in the figure below?

Let pplot and a toy problem be an example:

library(ggplot2)
pplot <- function(polygon){
  polygon <- lapply(polygon, function(x) {colnames(x) <- NULL; x})
  vertex_number = nrow(polygon[[1]])
  g = ggplot2::ggplot()
  names(polygon) = 1:length(polygon)
  k <- plyr::ldply(polygon, function(x) data.frame(x))
  g <- ggplot2::ggplot(k, ggplot2::aes(x = X1, y = X2, group = .id)) + ggplot2::geom_polygon(colour = "black", fill = NA)
  return(g)
}

a <- list()
b1 <- matrix(rnorm(6), ncol = 2)
b2 <- matrix(rnorm(6), ncol = 2)
b3 <- matrix(rnorm(6), ncol = 2)

a[[1]] <- b1
a[[2]] <- b2
a[[3]] <- b3

h <- c(.3, .5, .1)
#pplot function example
pplot(a) 

Graphic desired

Where the coordinate a = d , b = f , c = e are vertices and all information is in a .

Observation 1: The data must a list.

Observation 2: I've created a post in portuguese, but nobody answered. Can I do this or it is cheating? (I'm new here) https://pt.stackoverflow.com/questions/165538/plotar-figuras-3d-para-dados-em-lista

Answer 1

I'm not 100% sure I understood the task correctly. Nevertheless here's a draft for a solution with the package rgl . In my opinion it's still the best 3D plotting framework for R, because it's much faster and scales better than the javascript APIs (plotly, rthreejs etc.).

#### load package rgl ####
library(rgl)

set.seed(1232)

#### construct test list with coordinate matrices ####
a <- list()
b1 <- matrix(rnorm(6), ncol = 2)
b2 <- matrix(rnorm(6), ncol = 2)
b3 <- matrix(rnorm(6), ncol = 2)

a[[1]] <- b1
a[[2]] <- b2
a[[3]] <- b3

#### define test height vector ####
h <- c(.3, .5, .1)

#### simple plot prism function ####
# a: list with coordinate matrices
# h: height vector
plotprism <- function(a, h){
  # general loop to plot every prism
  for(i in 1:length(h)){
    # transform matrizes to data.frames and add height column 
    # -> separation of top and bottom triangle
    top <- data.frame(a[[i]], h[i]) 
    bottom <- data.frame(a[[i]], 0) 
    # adjust colnames to axis names
    colnames(top) <- c("x", "y", "z") 
    colnames(bottom) <- c("x", "y", "z") 
    # plot triangles (as wireframes)
    triangles3d(bottom, front = "line", back = "line")
    triangles3d(top, front = "line", back = "line")
    # plot vertical lines to connect the triangles
    for(i in 0:2){
      segments3d(
        x = c(bottom$x[1+i], top$x[1+i]),
        y = c(bottom$y[1+i], top$y[1+i]),
        z = c(bottom$z[1+i], top$z[1+i])
      )
    }
  }
  #### add coordinate system ####
  axes3d()
}

#### call plot function for test data ####
plotprism(a, h)

The results: