The plotly package is really useful for interactive plots. For example, we can plot the following function:
\[(x^2+\frac{9}{4}y^2+z^2-1)^3-x^2z^3-\frac{9}{200}y^2z^3=0\]
library(plotly)
# function
f <- function (x, y, z) {
return ((-1 + x^2 + (9/4)*y^2 + z^2)^3 - x^2*z^3 - (9/200)*y^2*z^3)
}
# coordinates
x <- seq(-1.5, 1.5, length.out = 30)
y <- x
z <- x
# create grid
grid <- expand.grid(x = x, y = y, z = z)
# value
grid$value <- with(grid, f(x,y,z))
# mutate roi to -1,0 or 1 according to value
threshold <- 0.02
grid$roi <- ifelse(grid$value < -1*threshold,-1,ifelse(grid$value > threshold,1,0))
# plot
plot_ly(subset(grid,roi<=1),x=~x, y=~y, z=~z, split=~roi,type="scatter3d", mode="markers",
color=~roi,size = I(30),symbol = I("square"),
colors=colorRampPalette(c("black","white", "red"))(101)[c(80,82,30)],
hovertemplate = paste('%{x:.4f} %{y:.4f} %{z:.4f}<br>'))%>% hide_colorbar()