R: Read and write STL (stereolithography) format files

readSTL {rgl} | R Documentation

## Read and write STL (stereolithography) format files

### Description

These functions read and write STL files. This is a simple file format that is commonly used in 3D printing. It does not represent text, only triangles. The `writeSTL` function converts some RGL object types to triangles.

### Usage

    readSTL(con, ascii = FALSE, plot = TRUE, ...)
    writeSTL(con, ascii = FALSE,
             pointRadius = 0.005,
             pointShape = icosahedron3d(),
             lineRadius = pointRadius,
             lineSides = 20,
             ids = NULL)

### Arguments

`con` | A connection or filename.
`ascii` | Whether to use the ASCII format or the binary format.
`plot` | On reading, should the object be plotted?
`...` | If plotting, other parameters to pass to `triangles3d`
`pointRadius, lineRadius` | The radius of points and lines relative to the overall scale of the figure.
`pointShape` | A mesh shape to use for points. It is scaled by the `pointRadius`.
`lineSides` | Lines are rendered as cylinders with this many sides.
`ids` | The identifiers (from `rgl.ids`) of the objects to write. If `NULL`, try to write everything.

### Details

The current implementation is limited. For reading, it ignores normals and color information. For writing, it only outputs triangles, quads, planes, spheres, points, line segments, line strips and surfaces, and does not write color information. Lines and points are rendered in an isometric scale: if your data scales vary, they will look strange.

Since the STL format only allows one object per file, all RGL objects are combined into a single object when output.

The output file is readable by Blender and Meshlab; the latter can write in a number of other formats, including U3D, suitable for import into a PDF document.

### Value

`readSTL` invisibly returns the object id if `plot = TRUE`, or (visibly) a matrix of vertices of the triangles if not.

`writeSTL` invisibly returns the name of the connection to which the data was written.

### Author(s)

Duncan Murdoch

### References

The file format was found on Wikipedia on October 25, 2012. I learned about the STL file format from David Smith's blog reporting on Ian Walker's `r2stl` function.

### See Also

`scene3d` saves a copy of a scene to an R variable; `writeWebGL`, `writeASY`, `writePLY`, `writeOBJ` and `writeSTL` write the scene to a file in various other formats.

### Examples

    filename <- tempfile(fileext = ".stl")
    open3d()
    shade3d( icosahedron3d(col = "magenta") )
    writeSTL(filename)
    open3d()
    readSTL(filename, col = "red")

[Package rgl version 0.99.9 Index]