toJSON(obj) {
        var json = BaseSerializer.prototype.toJSON.call(this, obj);

        json.type = obj.type;
        json.boundingBox = obj.boundingBox;
        json.boundingSphere = obj.boundingSphere;
        json.colors = obj.colors;
        json.colorsNeedUpdate = obj.colorsNeedUpdate;
        json.faces = obj.faces;
        json.faceVertexUvs = obj.faceVertexUvs;
        json.groupsNeedUpdate = obj.groupsNeedUpdate;
        json.isGeometry = obj.isGeometry;
        json.lineDistances = obj.lineDistances;
        json.lineDistancesNeedUpdate = obj.lineDistancesNeedUpdate;
        json.morphTargets = obj.morphTargets;
        json.morphNormals = obj.morphNormals;
        json.name = obj.name;
        json.normalsNeedUpdate = obj.normalsNeedUpdate;
        json.parameters = obj.parameters;
        json.skinWeights = obj.skinWeights;
        json.skinIndices = obj.skinIndices;
        json.uuid = obj.uuid;
        json.vertices = obj.vertices;
        json.verticesNeedUpdate = obj.verticesNeedUpdate;
        json.elementsNeedUpdate = obj.elementsNeedUpdate;
        json.uvsNeedUpdate = obj.uvsNeedUpdate;
        json.normalsNeedUpdate = obj.normalsNeedUpdate;

        return json;
    }
GeometrySerializer
@author tengge / https://github.com/tengge1