Resources Numerical accuracy Calculation policy
Draws the 3D check view with three.js and a DWG or DXF sheet on the canvas.
This code only draws. The 3D view hands its vertex lists to the graphics card as 32-bit floats; the canvas draws a CAD sheet's lines relative to a point near the data. No length, area, count or exported value comes from here.
2 calculations in 2 source files. The code is read from the released app when this page loads. It is the calculation people run, not a copy kept for this page.
Tests bin/test-takeoffcraft.mjs
Copies an object's triangles into a buffer for the graphics card.
THREE.Float32BufferAttribute converts the 64-bit vertex list to 32-bit for drawing. The object's reported quantities are not read from this buffer.
g.setAttribute('position', new THREE.Float32BufferAttribute(o.tris, 3));
g.computeVertexNormals();Tests bin/test-takeoffcraft-cad.mjs
Builds the canvas paths of one batch of lines and fills.
Coordinates are written relative to the first point of the batch and the offset is put back in the canvas transform, which keeps the path's numbers small when the view is zoomed in. Screen only.
/** Path2D for a batch, relative to an origin near its data (keeps float precision when zoomed in). */
function pathsFor(page, b) {
let p = page.paths.get(b);
if (p) return p;
const first = b.lines[0] || b.fills[0]?.rings[0] || [0, 0];
const ox = first[0] || 0, oy = first[1] || 0;
let lines = null;
if (b.lines.length) {
lines = new Path2D();
for (const pl of b.lines) {
lines.moveTo(pl[0] - ox, pl[1] - oy);
for (let i = 2; i < pl.length; i += 2) lines.lineTo(pl[i] - ox, pl[i + 1] - oy);
}
}
const fills = b.fills.map((f) => {
const path = new Path2D();
for (const r of f.rings) { path.moveTo(r[0] - ox, r[1] - oy); for (let i = 2; i < r.length; i += 2) path.lineTo(r[i] - ox, r[i + 1] - oy); path.closePath(); }
return { path, pattern: f.pattern };
});
p = { origin: [ox, oy], lines, fills };
page.paths.set(b, p);
return p;
}Computed to draw the screen, often in 32-bit on the graphics processor. No number a person reads, saves or exports comes from it.