As a beginner to three.js and 3D programming in general, I recently used three.js to draw a sector. However, I am facing an issue where I can only see the object in one direction but not in the opposite direction. It appears that the same phenomenon is happening in the example provided on the three.js website here. How can I make the object visible in both directions?
var squareShape = new THREE.Shape();
var arc = 1/6*Math.PI
var len = 20
squareShape.moveTo( 0,0 );
squareShape.absarc( 0, 0, 20, 4/3*Math.PI, 5/3*Math.PI, false );
squareShape.moveTo( 0, 0 );
var geometry = new THREE.ExtrudeGeometry( squareShape, {amount:0.1} );
var mesh = THREE.SceneUtils.createMultiMaterialObject( geometry, [ new THREE.MeshLambertMaterial( { color: 0xff0000 ,opacity: 1.0} ), new THREE.MeshBasicMaterial( { color: 0xff0000, wireframe: true, transparent: true ,opacity: 1.0} ) ] );
mesh.position.set( 10, 10, 10 );
mesh.rotation.set( Math.PI/2, 0, Math.PI/2 );
scene.add( mesh );