Plot3d: Plot3d generates a 3-dimensional plot using the package...
In p3d: Plot 3d data and fitted surfaces

Plot3d generates a 3-dimensional plot of points using the package rgl. A grid of points for the x and z variables and an optional factor variable is kept as an object in order to allowing plotting fitted surfaces that are functions of the x and z variables and the optional factor.

## S3 method for class 'formula'

Plot3d(formula = attr(data, "formula"),
    data = sys.parent(),
    groups = NULL,
    subset = NULL,
    xlab = names(dd)[2],
    ylab = names(dd)[1],
    zlab = names(dd)[3],
    verbose = 0,
    col = c("blue", "green", "orange", "magenta", "cyan", "red", "yellow", "gray"),
    surface = FALSE,
    fit = "smooth",
    surface.col = col,
    lines.col = "gray",
    lines.lwd = 1,
    ...)

## S3 method for class 'lm'

  Plot3d(fit, ...)

## S3 default method

  Plot3d(x, y, z, xlab, ylab, zlab, groups = NULL, ...)

`formula`	a two sided formula of the form `y ~ x + z \| [g]` where `y` is the variable plotted on the vertical axis, `x` is plotted on the horizontal axis and `z` is plotted along the axis coming out of the screen. `g` is interpreted as a factor and the index of its levels is used to select the value of `col` used.
`data`	a data frame in which `formula` is evaluated.
`groups`	a variable used to join points belonging to the same group by lines
`subset`	is a condition to select a subset of `data`.
`xlab, ylab, zlab`	labels for respective axes
`verbose`
`col`
`surface`
`fit`
`surface.col`
`lines.col`
`lines.lwd`
`...`

## Not run: 
    library(p3d)
    data(Smoking)
    head(Smoking)
    rownames(Smoking) = Smoking$Country

    Init3d(family = 'serif', cex = 1.5)
    Plot3d( LE ~ CigCon + HealthExpPC | Continent, Smoking)
    Axes3d()
    Identify3d(pad=1)


    fit = lm( LE ~ CigCon + log(HealthExpPC) +I(CigCon^2) + I(log(HealthExpPC)^2) + I(CigCon*log(HealthExpPC)), Smoking)
    Fit3d( fit )
    fitl <- lm( LE ~ CigCon + HealthExpPC, Smoking)
    Fit3d( fitl, col = 'pink')
# HEpCap is highly 'skewed': dense on left, long tail on right
    require( lattice )
    densityplot( Smoking$HealthExpPC )

# Useful to use a transformation to make spread more even
#  e.g. log
# First make sure all values are positive:

    sort( Smoking$HealthExpPC)

# Do log transformation:

    Smoking$LogHE <- log(Smoking$HealthExpPC)    # create log HE

    densityplot( Smoking$LogHE )

# Also usefult to have categories:

    Smoking$HECat <- cut(Smoking$LogHE, 7)       # create categories
    summary(Smoking)

    Plot3d( LE ~ CigCon + LogHE |HECat, Smoking )  # condition on level of HEpC
    Axes3d()
    Ell3d()
    Identify3d(pad=1)

# Simple regression

    fit.lin <- lm( LE ~ CigCon, Smoking)
    Fit3d( fit.lin )
    fit.lin2 <- lm(LE ~ CigCon, subset(Smoking, Continent != "Africa"))
    Fit3d( fit.lin2)
    Pop3d(4)

# Use multiple regression (advanced version with quadratic surface)

    fit = lm( LE ~ CigCon + I(LogHE^2) +I(CigCon^2) + I(LogHE^2) + I(CigCon*LogHE), Smoking)
    Fit3d( fit, col = 'red' )
    Pop3d(2)

# refit omitting Africa:

    fit.na = lm( LE ~ CigCon + I(LogHE^2) +I(CigCon^2) + I(LogHE^2)
               + I(CigCon*LogHE), Smoking, subset = Continent != "Africa")
    Fit3d( fit.na, col = 'red' )

# Marginal relationship

    Pop3d(4)    # pop twice for each fit
    fit.quad <- lm( LE ~ CigCon + I(CigCon^2) , Smoking)
    Fit3d( fit.quad, col = 'green')

#  A quadratic surface within each Continent (overfitting?!)

    fit2 = lm( LE ~ Continent*(CigCon + HealthExpPC +I(CigCon^2) +
            I(HealthExpPC^2) + I(CigCon*HealthExpPC)), Smoking)
    Fit3d( fit2 )

#  For a 2D view of the y versus x

    view3d(0,0,0)   # note the first parameter, theta, rotates clockwise in the vertical axis
                    # from the initial position given by view3d(0,0,0); the second
                    # parameter, phi, tilts the graph around a horizontal screen axis
                    # towards the viewer.  The third parameter, fov, affects the
                    # amount of 'perspective'. fov = 0 yields an orthographic
                    # projection

## End(Not run)