Added a check inside of the Projector.js to make sure that before accessing the 0th item of the

vertices array in the line geometry, that the length of the vertices array is more than 0.

    - This prevents crashing when a Line object is added to the scene before it has vertices
      added to it.

src/core/Projector.js

@@ -561,6 +561,8 @@ THREE.Projector = function () {
 
 					vertices = object.geometry.vertices;
 
+					if ( vertices.length === 0 ) continue;
+
 					v1 = getNextVertexInPool();
 					v1.positionScreen.copy( vertices[ 0 ] ).applyMatrix4( _modelViewProjectionMatrix );