如何在STL加载的BufferGeometry中平滑网格三角形

Question

我正在尝试使用Three.js加载一些STL文件.模型正确加载,但有太多的三角形我想合并/平滑.

我已经成功地在其他3D格式中应用了平滑的加载地形,但是我无法使用通过使用STLLoader加载STL文件而导致的BufferGeometry.

_

var material = new THREE.MeshLambertMaterial( { ... } );
var path = "./models/budah.stl";
var loader = new THREE.STLLoader();
loader.load( path, function ( object ) {
                object.computeBoundingBox();
                object.computeBoundingSphere();
                object.computeFaceNormals();
                object.computeVertexNormals();
                object.normalizeNormals();
                object.center();

                // Apply smooth
                var modifier = new THREE.SubdivisionModifier( 1);
                var smooth = smooth = object.clone();
                smooth.mergeVertices();
                smooth.computeFaceNormals();
                smooth.computeVertexNormals();
                modifier.modify( smooth );
                scene.add( smooth );
});

这是我试过的,它会抛出一个错误:Uncaught TypeError:smooth.mergeVertices不是一个函数

如果我评论"mergeVertices()"行,我得到的是一个不同的错误:Uncaught TypeError:无法读取 SubdivisionsModifier第156行中未定义的属性'length'.

似乎我尝试的示例代码已经过时(由于Three.JS库中的大量更改,这最近发生了很多).或者也许我忘了什么.事实是顶点似乎是空的..？

提前致谢!

Answer 1

看起来我看错了方向:平滑三角形与SubdivisionsModifier无关......我需要的比这更容易,只需在应用材质之前计算顶点,所以它可以使用SmoothShading而不是FlatShading(我做对了吗？)

这里的问题是STLLoader返回的BufferGeometry没有计算顶点/顶点,所以我不得不手动完成.之后,在computeVertexNormals()和voilà之前应用mergeVertices()!三角形消失了,一切都很平滑:

var material = new THREE.MeshLambertMaterial( { ... } );
var path = "./models/budah.stl";
var loader = new THREE.STLLoader();
loader.load( path, function ( object ) {                
                object.computeBoundingBox();
                object.computeVertexNormals();
                object.center();
                ///////////////////////////////////////////////////////////////

                var attrib = object.getAttribute('position');
                if(attrib === undefined) {
                    throw new Error('a given BufferGeometry object must have a position attribute.');
                }
                var positions = attrib.array;
                var vertices = [];
                for(var i = 0, n = positions.length; i < n; i += 3) {
                    var x = positions[i];
                    var y = positions[i + 1];
                    var z = positions[i + 2];
                    vertices.push(new THREE.Vector3(x, y, z));
                }
                var faces = [];
                for(var i = 0, n = vertices.length; i < n; i += 3) {
                    faces.push(new THREE.Face3(i, i + 1, i + 2));
                }

                var geometry = new THREE.Geometry();
                geometry.vertices = vertices;
                geometry.faces = faces;
                geometry.computeFaceNormals();              
                geometry.mergeVertices()
                geometry.computeVertexNormals();

                ///////////////////////////////////////////////////////////////
                var mesh = new THREE.Mesh(geometry, material);

                scene.add( mesh );
});