How to model corrugated roof panel

[BarbourSmith]

Hello!

I am trying to model a corrugated roof panel like this:

Any ideas on how to do that? I believe that the shape is sinusoidal.

Even harder, how would I model that when it's bent? IE a sinusoid around a circle?

[BarbourSmith]

I think that a parametric function like this might be the key 😃

https://replicad.xyz/docs/examples/cadquery-gear

[BarbourSmith]

I've got it mostly figured out like this:

const { drawCircle, drawParametricFunction } = replicad;

const main = () => {

//Define the sinewave function...Not currently used...d goes from 0:1 as the sinewave extends to full length
const sinewave = (d) => {
  const length = 1000;
  const period = 69.85;
  const amplitude = 22.225 / 2;
  const x = d * length; // Scale d to the total length
  const y = amplitude * Math.sin((2 * Math.PI * x) / period); // Scale the sine value by the amplitude and period
  return [x, y];
};

  //Define a circle
 const circleFunction = (t) => {
  const baseRadius = 300;

  const length = Math.PI*2*baseRadius;
  const period = 69.85;
  const amplitude = 22.225 / 2;
  const sinX = t * length; // Scale  to the total length (circumference)
  const sinY = amplitude * Math.sin((2 * Math.PI * sinX) / period)

  const angle = 2 * Math.PI * t;

  console.log(t)

  const radius = baseRadius + sinY;

  const circleX = radius * Math.cos(angle);
  const circleY = radius * Math.sin(angle);

  const x = circleX ;
  const y = circleY;


  return [x, y];
};

  //Create the sinewave shape
  const sinewaveShape = drawParametricFunction(circleFunction, { pointsCount: 400 });

  // Return the combined shape
  return sinewaveShape.sketchOnPlane().extrude(10);
;
};

The problem is that the circle is not closed. Got any tips on how to make it a closed shape? I know that there will be a sharp line at the point where it wraps around, but that is OK.

[sgenoud]

Neat! Any reason you are setting the period manually? You could compute it to avoid the step like here.

Note that if you need the wave period to be the one you specify you could change the radius of your circle to fit a full number of periods.

Otherwise you might as well have a logic that returns the first point when you get the last value:

 t = t === 1 ? 0: t

[BarbourSmith]

I'm stuck with the fixed period because it has to match the pitch of the meal roofing. I like the idea of constraining it to an integer number of periods or using t = t === 1 ? 0: t. I guess my real question was "If the start point and end point are the same is it actually closed, or do we need to do something to tell it that the shape is closed" and it sounds like the answer is that it's closed if the first and last point are the same.