Creating the 3D shapes

tip

You can click on the Open in workbench button in most code samples to see (and edit them) within the workbench.

We now have the basic drawing to create our 3D shapes:

• the can body for which we have a profile drawing
• the filler for which we have three well positioned circles
• the spout which is a simple cylinder

The spout cylinder

Creation of a cylinder

We have two different approaches we could take to create a cylinder:

• draw a circle and extrude it
• creating the cylinder with a direct function

Extrusion

To create a cylinder we can draw a circle, sketch it in 3D space, and then a extrude it.

const { drawCircle } = replicad;
const main = () => {
  return drawCircle(5).sketchOnPlane().extrude(70);
};

We have seen the first step in the previous page. We draw a circle and sketch it in the 3D space on a plane (here the default XY plane).

We extrude it, making a copy of itself in a certain direction and filling the sides.

using a direct creation method

const { makeCylinder } = replicad;
const main = () => {
  return makeCylinder(5, 70);
};

Positioning the shape

In the case of a circle that we extrude, we could place the plane to sketch on and then position it.

We have seen how to position a plane in 3D space, but we might want to position a 3D shape.

The operations are similar for a shape as for a plane. First, translations are identical.

const { makeCylinder } = replicad;
const main = () => {
  return makeCylinder(5, 70).translateZ(100);
};

Rotations are similar to pivots for planes - but as shapes do not have an origin point by default, we need to specify it.

const { makeCylinder } = replicad;
const main = () => {
  return makeCylinder(5, 70).translateZ(100).rotate(45, [0, 0, 100], [0, 1, 0]);
};

In order to make things more readable, we might want to rotate before we translate (with a different origin).

The can body

To create the can body we will use the profile we drew, sketch it on the XZ plane and rotate it around the Z axis:

const { draw } = replicad;

const main = () => {
  const profile = draw()
    .hLine(20)
    .line(10, 5)
    .vLine(3)
    .lineTo([8, 100])
    .hLine(-8)
    .close();

  return profile.sketchOnPlane("XZ").revolve([0, 0, 1]);
};

The filler

After extrusion and revolution, the filler uses a third method of 3D shape creation: lofting. We can create shapes by defining sections through which an object will pass trough.

We have defined our three circles and now we create a shape that passes through them all.

const { makePlane, drawCircle } = replicad;

const main = () => {
  const topPlane = makePlane().pivot(-20, "Y").translate([-35, 0, 135]);
  const topCircle = drawCircle(12).sketchOnPlane(topPlane);

  const middleCircle = drawCircle(8).sketchOnPlane("XY", 100);

  const bottomPlane = makePlane().pivot(20, "Y").translateZ(80);
  const bottomCircle = drawCircle(9).sketchOnPlane(bottomPlane);

  return topCircle.loftWith([middleCircle, bottomCircle], { ruled: false });
};

Putting it all together

Let's show all the pieces we have built so far together

const { makePlane, makeCylinder, draw, drawCircle } = replicad;

const main = () => {
  // Building the body
  const profile = draw()
    .hLine(20)
    .line(10, 5)
    .vLine(3)
    .lineTo([8, 100])
    .hLine(-8)
    .close();

  const body = profile.sketchOnPlane("XZ").revolve([0, 0, 1]);

  // Building the spout
  const topPlane = makePlane().pivot(-20, "Y").translate([-35, 0, 135]);
  const topCircle = drawCircle(12).sketchOnPlane(topPlane);

  const middleCircle = drawCircle(8).sketchOnPlane("XY", 100);

  const bottomPlane = makePlane().pivot(20, "Y").translateZ(80);
  const bottomCircle = drawCircle(9).sketchOnPlane(bottomPlane);

  const filler = topCircle.loftWith([middleCircle, bottomCircle], {
    ruled: false,
  });

  const spout = makeCylinder(5, 70)
    .translateZ(100)
    .rotate(45, [0, 0, 100], [0, 1, 0]);

  return [
    { shape: body, color: "blue", opacity: 0.5 },
    { shape: filler, color: "red", opacity: 0.5 },
    { shape: spout, color: "green" },
  ];
};