@amandaghassaei/stl-parser
Standalone module for loading and parsing binary/ASCII STL files – unit tested and written in TypeScript. Parsing code based on Threejs STLLoader.
Live demo: apps.amandaghassaei.com/stl-parser/demo/
STL File Format
The .stl file format stores geometry (and sometimes color) information for 3D triangulated meshes. stl-parser does not generate or render .stl files, but it will allow you to parse them in a browser or Nodejs environment. Example .stl files can be found in test/stl/.
Installation
Install via npm
npm install @amandaghassaei/stl-parserand import into your project:
import {
parseSTL,
loadSTL,
loadSTLAsync,
} from '@amandaghassaei/stl-parser';Import into HTML
Import stl-parser.min.js directly into your html:
<html>
<head>
<script src="stl-parser.min.js"></script>
</head>
<body>
</body>
</html>STLParserLib will be accessible globally:
const { parseSTL, loadSTL, loadSTLAsync } = STLParserLib;Use
Full API documentation in docs.
// Load and parse the .stl file using url or File object.
loadSTL('./teapot.stl', (mesh) => {
const {
vertices,
facesNormals,
facesColors,
edgesIndices,
boundingBox,
} = mesh;
});
// Also try:
// const mesh = await loadSTLAsync('./teapot.stl');
// Or parse file buffer or string synchronously.
const meshFromBuffer = parseSTL(fs.readFileSync('./teapot.stl'));
const meshFromString = parseSTL(`solid ASCII
facet normal 0.000000e+00 0.000000e+00 -1.000000e+00
outer loop
vertex 1.000000e+01 0.000000e+00 -1.000000e+01
vertex 0.000000e+00 0.000000e+00 -1.000000e+01
vertex 1.000000e+01 1.000000e+01 -1.000000e+01
endloop
endfacet
....
facet normal 0.000000e+00 -1.000000e+00 0.000000e+00
outer loop
vertex 0.000000e+00 0.000000e+00 0.000000e+00
vertex 1.000000e+01 0.000000e+00 -1.000000e+01
vertex 1.000000e+01 0.000000e+00 0.000000e+00
endloop
endfacet
endsolid`);-
verticesis a Float32Array of length 3 * numVertices containing a flat list of vertex positions in the following order[x0, y0, z0, x1, y1, z1, ...]. Each group of three vertices make up a triangle in the .stl mesh – by default, vertices are not shared between triangles in the .stl format, seemergeVertices()below. -
facesNormalsis a Float32Array of length 3 * numFaces containing a flat list of face normals in the following order[nx0, ny0, nz0, nx1, ny1, nz1, ...] - If available,
facesColorsis a Float32Array of length 3 * numFaces containing a flat list of face colors in the following order[r0, g0, b0, r1, g1, b1, ...]. -
edgesIndicesis a Uint32Array containing all unique edgesIndices (expressed as pairs of vertex indices) in the mesh in the following order:[e01, e02, e11, e12, ...].edgesIndicesis calculated when queried and then cached. -
boundingBoxreturns the min and max of the mesh's bounding box in the form:{ min: [x, y, z], max: [x, y, z] }.boundingBoxis calculated when queried and then cached.
The mesh object returned by parseSTL, loadSTL, and loadSTLAsync also exposes methods for modifying its geometry:
mesh.mergeVertices().scaleVerticesToUnitBoundingBox();
const { facesIndices } = mesh;-
STLMesh.mergeVertices()merges coincident vertices and adds afacesIndicesarray to the mesh object.facesIndiceshas length 3 * numFaces and contains a flat list of triangle face vertex indices in the following order:[v01, v02, v03, v11, v12, v13, ...]. -
STLMesh.scaleVerticesToUnitBoundingBox()scales theverticesvalues (in place) to fit inside a unit box centered around the origin.
Build Notes
This library imports fs in Nodejs environments to load files from a url string. This code is never hit in the browser environment (the browser uses a XMLHttpRequest instead), but you may see build warnings due to the import('fs') statement in the code. (I'm wondering if there is a better way to handle this that is compatible for both Nodejs and browser environments, please let me know if you have ideas.)
To fix this warning, you need to set fs as an external dependency in your build settings:
// rollup.config.js
export default {
...
external: ['fs'],
};// vite.config.js
export default {
build: {
rollupOptions: {
external: ['fs'],
},
}
...
}Limitations
- See limitations listed in Threejs STLLoader. If you have a file that is not being parsed correctly, please upload it in an Issue so it can be added as a test case. Pull requests welcome.
Acknowledgements
License
This work is licensed under an MIT License. It depends on the following:
- @amandaghassaei/3d-mesh-utils - geometry processing utility functions for 3D meshes (MIT license)
Related Libraries
- msh-parser - finite element .msh format parser
Development
I don't have any plans to continue developing this package, but I'm happy to review pull requests if you would like to add a new feature / fix a bug.
To install dev dependencies:
npm installTo compile src to dist:
npm run buildTesting
To run tests:
npm run test