function to simplify adding points3d

[wiesehahn]

We can plot a pointcloud and add raster or spatial points like:

x <- plot(las)
add_dtm3d(x, dtm)
add_treetops3d(x, ttops)

plot(las) |> add_dtm3d(dtm) |> add_treetops3d(ttops)

and we can plot a pointcloud and add another pointcloud like:

x <- plot(las)
plot(las2, add=x)

would it make sense to add something like add_points3d, so that its possible to apply plot(las) |> add_points3d(las2)?
I guess its not necessary and probably not used very often but I was just looking for something like this.

[Jean-Romain]

This is definitively doable