Orthographic Projections

Historically technical drawing consisted of a lot of orthographic projections. In some cases it still is a great method of communication for 3D models.

Replicad support projections into a drawing (and therefore a projection as an SVG). This code follows the first angle convention.

And here is what the code looks like.

const { drawProjection, draw } = replicad;

/* This follow the "first angle projection" convention
 * https://en.wikipedia.org/wiki/Multiview_orthographic_projection#First-angle_projection
 */
const descriptiveGeom = (shape) => {
  return [
    { shape, name: "Shape to project" },
    { shape: drawProjection(shape, "front").visible, name: "Front" },
    { shape: drawProjection(shape, "back").visible, name: "Back" },
    { shape: drawProjection(shape, "top").visible, name: "Top" },
    { shape: drawProjection(shape, "bottom").visible, name: "Bottom" },
    { shape: drawProjection(shape, "left").visible, name: "Left" },
    { shape: drawProjection(shape, "right").visible, name: "Right" },
  ];
};

const main = () => {
  // This shape looks different from every angle
  const shape = draw()
    .vLine(-10)
    .hLine(-5)
    .vLine(15)
    .customCorner(2)
    .hLine(15)
    .vLine(-5)
    .close()
    .sketchOnPlane()
    .extrude(10)
    .chamfer(5, (e) => e.inPlane("XY", 10).containsPoint([10, 1, 10]));

  return descriptiveGeom(shape);
};

Custom perspectives

You can also have nice looking perspectives on your shapes.

const { drawProjection, ProjectionCamera, draw } = replicad;

const prettyProjection = (shape) => {
  const bbox = shape.boundingBox;
  const center = bbox.center;
  const corner = [
    bbox.center[0] + bbox.width,
    bbox.center[1] - bbox.height,
    bbox.center[2] + bbox.depth,
  ];
  const camera = new ProjectionCamera(corner).lookAt(center);
  const { visible, hidden } = drawProjection(shape, camera);

  return [
    { shape: hidden, strokeType: "dots", name: "Hidden Lines" },
    { shape: visible, name: "Visible Lines" },
  ];
};

const main = () => {
  const shape = draw()
    .vLine(-10)
    .hLine(-5)
    .vLine(15)
    .customCorner(2)
    .hLine(15)
    .vLine(-5)
    .close()
    .sketchOnPlane()
    .extrude(10)
    .chamfer(5, (e) => e.inPlane("XY", 10).containsPoint([10, 1, 10]));

  return prettyProjection(shape);
};