问题
I'm having difficulties constructing a hollow cylinder in Three.js.
Should I go and construct it using CSG or by stitching the vertices together?
回答1:
This solution uses ChandlerPrall's ThreeCSG.js project: http://github.com/chandlerprall/ThreeCSG
(For now, I recommend using the experimental version that supports materials - the uv branch - http://github.com/chandlerprall/ThreeCSG/tree/uvs)
Here's the code you will need:
// Cylinder constructor parameters:
// radiusAtTop, radiusAtBottom, height, segmentsAroundRadius, segmentsAlongHeight
var smallCylinderGeom = new THREE.CylinderGeometry( 30, 30, 80, 20, 4 );
var largeCylinderGeom = new THREE.CylinderGeometry( 40, 40, 80, 20, 4 );
var smallCylinderBSP = new ThreeBSP(smallCylinderGeom);
var largeCylinderBSP = new ThreeBSP(largeCylinderGeom);
var intersectionBSP = largeCylinderBSP.subtract(smallCylinderBSP);
var redMaterial = new THREE.MeshLambertMaterial( { color: 0xff0000 } );
var hollowCylinder = intersectionBSP.toMesh( redMaterial );
scene.add( hollowCylinder );
回答2:
var extrudeSettings = {
amount : 2,
steps : 1,
bevelEnabled: false,
curveSegments: 8
};
var arcShape = new THREE.Shape();
arcShape.absarc(0, 0, 1, 0, Math.PI * 2, 0, false);
var holePath = new THREE.Path();
holePath.absarc(0, 0, 0.8, 0, Math.PI * 2, true);
arcShape.holes.push(holePath);
var geometry = new THREE.ExtrudeGeometry(arcShape, extrudeSettings);
回答3:
It is unlikely that you would have to stitch vertices together. If your cylinder has no thickness, you can use THREE.CylinderGeometry()
. If it does have thickness, you can use CSG.
回答4:
Use SVGloader to load a circle of desired radius (as an SVG). Set the geometry to ExtrudeBufferGeometry and give it your desired height as depth in the extrude settings object.
来源:https://stackoverflow.com/questions/11826798/how-do-i-construct-a-hollow-cylinder-in-three-js