code: function (x, y, forcePickAll) {
          var out = this.pickAll(x, y, [], forcePickAll);
          return out[0] || null;
      }
docs: Pick the nearest intersection object in the scene
  @param  {number} x Mouse position x
  @param  {number} y Mouse position y
  @param  {boolean} [forcePickAll=false] ignore ignorePicking
  @return {clay.picking.RayPicking~Intersection}