This function “turns” the curve (as on a lathe) to form a
solid of rotation along the x axis.

`turn3d(x, y = NULL, n = 12, smooth = FALSE, ...)`

## Arguments

x, y |
Points on the curve, in a form suitable for `xy.coords` .
The `y` values must be non-negative. |

n |
How many steps in the rotation? |

smooth |
logical; whether to add normals for a smooth appearance. |

... |
Additional parameters to pass to `tmesh3d` . |

## Value

A mesh object containing triangles and/or quadrilaterals.

## Author

Fang He and Duncan Murdoch

## See also

## Examples

```
x <- 1:10
y <- rnorm(10)^2
shade3d(turn3d(x, y), col = "green")
```