solved How can I make a lathe shape radially smooth, but axially flat?

[xiphiaz]

See my example: https://www.babylonjs-playground.com/#165IV6#435

I have a lathe mesh that is a swept surface, that I want to appear smooth around the surface, but not have the vertex normals be vertically smooth (if that makes sense?). Basically without converting to flat mesh, the normals make it appear to curve around hard edges that should remain to be hard.

 

Is there a way I can update the normals to make it appear to have hard edges, but not be faceted on the cylindrical surfaces?

[Guest]

Pinging our lathe master: @jerome

[Pryme8]

https://www.babylonjs-playground.com/#165IV6#436

[jerome]

https://www.babylonjs-playground.com/#165IV6#439

What did I do ? I just repeated the points in the list where the normals musn't be smoothed.

Nice hack Pryme8 ?

[xiphiaz]

Awesome thanks @jerome & @Pryme8. For completeness this is what I ended up with.

 

```ts

private generateFlatLathe(name: string, shape: Vector3[]): Mesh {
  return MeshBuilder.CreateLathe(
    name,
    {
      shape: shape.reduce((duplicatedPoints, point, index, allPoints) => {
        // only duplicate the non start & end points
        index !== 0 && index < allPoints.length - 1
          ? duplicatedPoints.push(point, point)
          : duplicatedPoints.push(point);
        return duplicatedPoints;
      }, []),
    },
    this.scene
  );
}

```

[Pryme8]

That is clean.