如何在R语言3D绘图中实现所有点对的连线？

你当前使用scatter3D(type = "b")只能按数据行顺序连接点（即绘制点的路径），无法实现所有点两两之间的连线。下面提供两种可行的解决方案：

方法一：基于plot3D包实现 #

通过生成所有点对的组合，再逐个绘制每对点之间的连线：

library(tidyverse)
library(plot3D)

# 构造数据
df <- data.frame(dim1 = rnorm(n = 20), dim2 = rnorm(n = 20), dim3 = rnorm(n = 20))

# 先绘制散点
scatter3D(
    x = df$dim1,
    y = df$dim2,
    z = df$dim3,
    pch = 20,
    xlab = "Dimension 1",
    ylab = "Dimension 2",
    zlab = "Dimension 3",
    phi = 40,
    bty = "b",
    cex = 2
)

# 生成所有不重复的点对索引
point_pairs <- combn(nrow(df), 2)

# 遍历每个点对，绘制连线
for (i in 1:ncol(point_pairs)) {
    idx1 <- point_pairs[1, i]
    idx2 <- point_pairs[2, i]
    lines3D(
        x = c(df$dim1[idx1], df$dim1[idx2]),
        y = c(df$dim2[idx1], df$dim2[idx2]),
        z = c(df$dim3[idx1], df$dim3[idx2]),
        col = "gray", # 用灰色区分点和线
        lwd = 0.5
    )
}

方法二：基于rgl包实现（支持3D交互） #

rgl包提供了交互式的3D绘图功能，实现全点对连线更高效：

library(rgl)
library(tidyverse)

# 构造数据
df <- data.frame(dim1 = rnorm(n = 20), dim2 = rnorm(n = 20), dim3 = rnorm(n = 20))

# 绘制3D散点
plot3d(
    x = df$dim1,
    y = df$dim2,
    z = df$dim3,
    pch = 20,
    size = 2,
    xlab = "Dimension 1",
    ylab = "Dimension 2",
    zlab = "Dimension 3",
    col = "black"
)

# 生成所有点对的坐标矩阵
point_pairs <- combn(nrow(df), 2)
segments_x <- df$dim1[point_pairs]
segments_y <- df$dim2[point_pairs]
segments_z <- df$dim3[point_pairs]

# 批量绘制所有连线
segments3d(
    x = segments_x,
    y = segments_y,
    z = segments_z,
    col = "gray",
    lwd = 0.5
)

内容的提问来源于stack exchange，提问作者Ladislas Nalborczyk