code: function ( face, geometry, useCachedAreas ) {
  
  		var vA, vB, vC, vD;
  
  		vA = geometry.vertices[ face.a ];
  		vB = geometry.vertices[ face.b ];
  		vC = geometry.vertices[ face.c ];
  
  		return THREE.GeometryUtils.randomPointInTriangle( vA, vB, vC );
  
  	}
docs: Get random point in face (triangle / quad) (uniform distribution)