# plot3d.lm

##### Method for plotting simple linear fit.

This function provides several plots of the result of fitting a two-predictor model.

##### Usage

```
# S3 method for lm
plot3d(x,
which = 1,
plane.col = "gray", plane.alpha = 0.5,
sharedMouse = TRUE,
use_surface3d,
do_grid = TRUE,
grid.col = "black",
grid.alpha = 1,
grid.steps = 5,
sub.steps = 4,
vars = get_all_vars(terms(x), x$model),
...)
```

##### Arguments

- x
An object inheriting from class

`"lm"`

obtained by fitting a two-predictor model.- which
Which plot to show? See Details below.

- plane.col, plane.alpha
These parameters control the colour and transparency of a plane or surface.

- sharedMouse
If multiple plots are requested, should they share mouse controls, so that they move in sync?

- use_surface3d
Use the

`surface3d`

function to plot the surface rather than`planes3d`

. This allows curved surfaces to be shown. The default is`FALSE`

if the model looks like a simple 2 parameter linear fit, otherwise`TRUE`

.- do_grid
Plot a grid.

- grid.col, grid.alpha, grid.steps
Characteristics of the grid.

- sub.steps
If

`use_surface3d`

is`TRUE`

, use an internal grid of`grid.steps*sub.steps`

to draw the surface.`sub.steps > 1`

allows curvature within facets. Similarly, if`do_grid`

is`TRUE`

, it allows curvature within grid lines.- vars
A dataframe containing the variables to plot in the first three columns, with the response assumed to be in column 1. See the Note below.

- …
Other parameters to pass to the default

`plot3d`

method, to control the appearance of aspects of the plot other than the plane.

##### Details

Three plots are possible, depending on the value(s) in `which`

:

(default) Show the points and the fitted plane.

Show the residuals and the plane at

`z = 0`

.Show the predicted values on the fitted plane.

##### Value

Called for the side effect of drawing one or more plots.

Invisibly returns a high-level vector of object ids. Names of object ids have the plot number (in drawing order) appended.

##### Note

The default value for the `vars`

argument will handle
simple linear models with a response and two predictors, and
some models with functions of those two predictors. For
models that fail (e.g. models using `poly`

), you
can include the observed values as in the third example below.

##### Examples

```
# NOT RUN {
open3d()
ids <- plot3d(lm(mpg ~ wt + qsec, data = mtcars), which = 1:3)
names(ids)
open3d()
plot3d(lm(mpg ~ wt + I(wt^2) + qsec, data = mtcars))
open3d()
# Specify vars in the order: response, pred1, pred2.
plot3d(lm(mpg ~ poly(wt, 3) + qsec, data = mtcars),
vars = mtcars[,c("mpg", "wt", "qsec")])
# }
```

*Documentation reproduced from package rgl, version 0.100.50, License: GPL*