Three.js OBJExporter, updated to work with bufferGeometry. Adds support for bones and morph data.

OBJExporter.js

THREE.OBJExporter = function () {};

THREE.OBJExporter.prototype = {

	constructor: THREE.OBJExporter,

	parse: function (object) {

		var output = '';

		var indexVertex = 0;
		var indexVertexUvs = 0;
		var indexNormals = 0;

		var vertex = new THREE.Vector3();
		var normal = new THREE.Vector3();
		var uv = new THREE.Vector2();

		var i,
		j,
		l,
		m,
		face = [];

		var parseMesh = function (mesh) {

			var nbVertex = 0;
			var nbNormals = 0;
			var nbVertexUvs = 0;

			var geometry = mesh.geometry;

			var normalMatrixWorld = new THREE.Matrix3();

			if (geometry instanceof THREE.Geometry) {

				geometry = new THREE.BufferGeometry().setFromObject(mesh);

			}

			if (geometry instanceof THREE.BufferGeometry) {

				var vertices = geometry.getAttribute('position');
				var normals = geometry.getAttribute('normal');
				var uvs = geometry.getAttribute('uv');
				var indices = geometry.getIndex();
				var skinIndices = geometry.getAttribute('skinIndex');
				var weights = geometry.getAttribute('skinWeight');
				var morphVector;
				// name of the mesh object
				output += 'o ' + mesh.name + '\n';

				// vertices

				if (vertices !== undefined) {

					for (i = 0, l = vertices.count; i < l; i++, nbVertex++) {
						if (skinIndices == undefined) {

							vertex.x = vertices.getX(i);
							vertex.y = vertices.getY(i);
							vertex.z = vertices.getZ(i);

							//vertex.applyMatrix4(mesh.matrixWorld);
							output += 'v ' + vertex.x + ' ' + vertex.y + ' ' + vertex.z + '\n';
						} else {

							vertex.x = vertices.getX(i);
							vertex.y = vertices.getY(i);
							vertex.z = vertices.getZ(i);
							//vertex.applyMatrix4(mesh.matrixWorld);

							skinIndex = [];
							skinIndex[0] = skinIndices.getX(i);
							skinIndex[1] = skinIndices.getY(i);
							skinIndex[2] = skinIndices.getZ(i);
							skinIndex[3] = skinIndices.getW(i);

							skinWeight = [];
							skinWeight[0] = weights.getX(i);
							skinWeight[1] = weights.getY(i);
							skinWeight[2] = weights.getZ(i);
							skinWeight[3] = weights.getW(i);

							inverses = [];
							inverses[0] = mesh.skeleton.boneInverses[skinIndex[0]];
							inverses[1] = mesh.skeleton.boneInverses[skinIndex[1]];
							inverses[2] = mesh.skeleton.boneInverses[skinIndex[2]];
							inverses[3] = mesh.skeleton.boneInverses[skinIndex[3]];

							skinMatrices = [];
							skinMatrices[0] = mesh.skeleton.bones[skinIndex[0]].matrixWorld;
							skinMatrices[1] = mesh.skeleton.bones[skinIndex[1]].matrixWorld;
							skinMatrices[2] = mesh.skeleton.bones[skinIndex[2]].matrixWorld;
							skinMatrices[3] = mesh.skeleton.bones[skinIndex[3]].matrixWorld;

							var finalVector = new THREE.Vector4();

							if (geometry.morphTargetInfluences !== undefined) {
								var morphAttributes = geometry.morphAttributes.position;
								//console.log("Mesh Name:" + mesh.name);
								morphMatricesX = [];
								morphMatricesY = [];
								morphMatricesZ = [];
								morphMatricesInfluence = [];

								var morphLength = geometry.morphAttributes.position.length;
								//console.log("Morph Length " + morphLength);
								for (var mt = 0; mt < morphLength; mt++) {
									//collect the needed vertex info
									morphMatricesX[mt] = morphAttributes[mt].getX(i);
									morphMatricesY[mt] = morphAttributes[mt].getY(i);
									morphMatricesZ[mt] = morphAttributes[mt].getZ(i);
									morphMatricesInfluence[mt] = mesh.morphTargetInfluences[mt];

								}

							}

							if (geometry.morphTargetInfluences !== undefined) {

								morphVector = new THREE.Vector4(vertex.x, vertex.y, vertex.z);
								var morphLength = geometry.morphAttributes.position.length;
								for (var mt = 0; mt < morphLength; mt++) {
									//not pretty, but it gets the job done
									morphVector.lerp(new THREE.Vector4(morphMatricesX[mt], morphMatricesY[mt], morphMatricesZ[mt], 1), morphMatricesInfluence[mt]);
								}

							}

							for (var k = 0; k < 4; k++) {
								if (geometry.morphTargetInfluences !== undefined) {
									var tempVector = new THREE.Vector4(morphVector.x, morphVector.y, morphVector.z);
								} else {
									var tempVector = new THREE.Vector4(vertex.x, vertex.y, vertex.z);
								}

								tempVector.multiplyScalar(skinWeight[k]);
								//the inverse takes the vector into local bone space
								//which is then transformed to the appropriate world space
								tempVector.applyMatrix4(inverses[k]).applyMatrix4(skinMatrices[k]);
								finalVector.add(tempVector);

							}

							// transform the vertex to export format
							output += 'v ' + finalVector.x + ' ' + finalVector.y + ' ' + finalVector.z + '\n';
						}

					}

				}

				// uvs

				if (uvs !== undefined) {

					for (i = 0, l = uvs.count; i < l; i++, nbVertexUvs++) {

						uv.x = uvs.getX(i);
						uv.y = uvs.getY(i);

						// transform the uv to export format
						output += 'vt ' + uv.x + ' ' + uv.y + '\n';

					}

				}

				// normals

				if (normals !== undefined) {

					normalMatrixWorld.getNormalMatrix(mesh.matrixWorld);

					for (i = 0, l = normals.count; i < l; i++, nbNormals++) {

						normal.x = normals.getX(i);
						normal.y = normals.getY(i);
						normal.z = normals.getZ(i);

						// transfrom the normal to world space
						normal.applyMatrix3(normalMatrixWorld);

						// transform the normal to export format
						output += 'vn ' + normal.x + ' ' + normal.y + ' ' + normal.z + '\n';

					}

				}

				// faces

				if (indices !== null) {

					for (i = 0, l = indices.count; i < l; i += 3) {

						for (m = 0; m < 3; m++) {

							j = indices.getX(i + m) + 1;

							face[m] = (indexVertex + j) + '/' + (uvs ? (indexVertexUvs + j) : '') + '/' + (indexNormals + j);

						}

						// transform the face to export format
						output += 'f ' + face.join(' ') + "\n";

					}

				} else {

					for (i = 0, l = vertices.count; i < l; i += 3) {

						for (m = 0; m < 3; m++) {

							j = i + m + 1;

							face[m] = (indexVertex + j) + '/' + (uvs ? (indexVertexUvs + j) : '') + '/' + (indexNormals + j);

						}

						// transform the face to export format
						output += 'f ' + face.join(' ') + "\n";

					}

				}

			} else {

				console.warn('THREE.OBJExporter.parseMesh(): geometry type unsupported', geometry);

			}

			// update index
			indexVertex += nbVertex;
			indexVertexUvs += nbVertexUvs;
			indexNormals += nbNormals;

		};

		var parseLine = function (line) {

			var nbVertex = 0;

			var geometry = line.geometry;
			var type = line.type;

			if (geometry instanceof THREE.Geometry) {

				geometry = new THREE.BufferGeometry().setFromObject(line);

			}

			if (geometry instanceof THREE.BufferGeometry) {

				// shortcuts
				var vertices = geometry.getAttribute('position');
				var indices = geometry.getIndex();

				// name of the line object
				output += 'o ' + line.name + '\n';

				if (vertices !== undefined) {

					for (i = 0, l = vertices.count; i < l; i++, nbVertex++) {

						vertex.x = vertices.getX(i);
						vertex.y = vertices.getY(i);
						vertex.z = vertices.getZ(i);

						// transfrom the vertex to world space
						vertex.applyMatrix4(line.matrixWorld);

						// transform the vertex to export format
						output += 'v ' + vertex.x + ' ' + vertex.y + ' ' + vertex.z + '\n';

					}

				}

				if (type === 'Line') {

					output += 'l ';

					for (j = 1, l = vertices.count; j <= l; j++) {

						output += (indexVertex + j) + ' ';

					}

					output += '\n';

				}

				if (type === 'LineSegments') {

					for (j = 1, k = j + 1, l = vertices.count; j < l; j += 2, k = j + 1) {

						output += 'l ' + (indexVertex + j) + ' ' + (indexVertex + k) + '\n';

					}

				}

			} else {

				console.warn('THREE.OBJExporter.parseLine(): geometry type unsupported', geometry);

			}

			// update index
			indexVertex += nbVertex;

		};

		object.traverse(function (child) {

			if (child instanceof THREE.Mesh) {

				parseMesh(child);

			}

			if (child instanceof THREE.Line) {

				parseLine(child);

			}

		});

		return output;

	}

};

Hi there.
Thanks for the gist.
Works great.
I am having troubles adding morphNormals into the export process, in order to fully support morph targets export.

Will be happy to hear if you have a direction.

Hey, I'm trying to export a humanoid model, but I have some problems:
First of all, the attributes name are skinIndex0 and skinWeigth0, so I had to change the code to:

var skinIndices = geometry.getAttribute('skinIndex0');
var weights = geometry.getAttribute('skinWeight0');

otherwise the exported model is in T pose.

But, after this change, the exported model is a mess:

Do you have any idea why?

Do you have any idea why?

How you did it get working?

Do you have any idea why?

How you did it get working?

What do you mean "working"? My example doesn't work at all, the exported model is a complete random mess

I know, I ask about how you config it to arrive to this mesh, I can get as T pose fairly but no more.

…

El 1 nov 2020, a las 9:45, Emmanuele Villa ***@***.***> escribió: ***@***.*** commented on this gist. Do you have any idea why? How you did it get working? What do you mean "working"? My example doesn't work at all, the exported model is a complete random mess — You are receiving this because you commented. Reply to this email directly, view it on GitHub <https://gist.github.com/35b19f811c657ec73b0238d78413f88d#gistcomment-3512061>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABPMFVQU6KKUCXP77MWB2P3SNUN2NANCNFSM4SL7JYSQ>.

I know, I ask about how you config it to arrive to this mesh, I can get as T pose fairly but no more.
…
El 1 nov 2020, a las 9:45, Emmanuele Villa @.***> escribió: @EmmanueleVilla commented on this gist. Do you have any idea why? How you did it get working? What do you mean "working"? My example doesn't work at all, the exported model is a complete random mess — You are receiving this because you commented. Reply to this email directly, view it on GitHub https://gist.github.com/35b19f811c657ec73b0238d78413f88d#gistcomment-3512061, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABPMFVQU6KKUCXP77MWB2P3SNUN2NANCNFSM4SL7JYSQ.

I've changed the two lines that I wrote in my first comment, from skinWeigth to skinWeight0

Does this work ?