code: function PBRBaseSimpleMaterial(name, scene) {
                  var _this = _super.call(this, name, scene) || this;
                  /**
                   * Number of Simultaneous lights allowed on the material.
                   */
                  _this.maxSimultaneousLights = 4;
                  /**
                   * If sets to true, disables all the lights affecting the material.
                   */
                  _this.disableLighting = false;
                  /**
                   * If sets to true, x component of normal map value will invert (x = 1.0 - x).
                   */
                  _this.invertNormalMapX = false;
                  /**
                   * If sets to true, y component of normal map value will invert (y = 1.0 - y).
                   */
                  _this.invertNormalMapY = false;
                  /**
                   * Emissivie color used to self-illuminate the model.
                   */
                  _this.emissiveColor = new BABYLON.Color3(0, 0, 0);
                  /**
                   * Occlusion Channel Strenght.
                   */
                  _this.occlusionStrength = 1.0;
                  _this._transparencyMode = BABYLON.PBRMaterial.PBRMATERIAL_OPAQUE;
                  _this._useAmbientInGrayScale = true;
                  return _this;
              }
docs: Instantiates a new PBRMaterial instance.
  
  @param name The material name
  @param scene The scene the material will be use in.