Adding Wall Thickness to a LatheGeometry Shape

Based on your question about adding thin wall thickness to a shape created with Path and LatheGeometry, I can suggest a few approaches.

Understanding the Problem

You've created a custom shape using Path methods like .lineTo() and .arc(), then used .getPoints() to generate points for a LatheGeometry. Now you need to add a thin wall thickness to this shape.

Solution Approaches

1. Create Two Offset Paths

The most straightforward approach would be to create two separate paths:

• An outer path (your current path)
• An inner path (offset inward by your desired wall thickness)

Then use both paths to create a single shape with thickness.

2. Using ExtrudeGeometry with LatheGeometry

You could:

1. Create your original path
2. Create a second path offset inward
3. Connect these paths to form a closed shape
4. Use this shape with LatheGeometry

Implementation Example

Here's how you might implement the first approach:

JAVASCRIPTCopied
// Create the outer path (your current path)
const outerPath = new THREE.Path();
// Your existing path code here...

// Create the inner path (offset inward)
const innerPath = new THREE.Path();
// Similar to outer path but with coordinates offset inward by wall thickness

// Get points from both paths
const outerPoints = outerPath.getPoints(50);
const innerPoints = innerPath.getPoints(50);

// Combine points for a LatheGeometry with thickness
const allPoints = [...outerPoints, ...innerPoints.reverse()];

// Create a custom BufferGeometry
const geometry = new THREE.BufferGeometry();
// Set up the geometry with vertices and faces...

// Or use a different approach with ShapeGeometry + LatheGeometry

Alternative Approach

Another approach would be to create your shape normally with LatheGeometry, then use a second slightly smaller LatheGeometry and perform a Boolean subtraction operation. This would require a CSG (Constructive Solid Geometry) library like ThreeBSP or using the newer THREE-CSG-Mesh library.

I recommend examining your CodePen in more detail and potentially exploring the Shape and ShapePath classes from the Extras/Core section of Three.js, as they might provide additional functionality for creating complex shapes with thickness.