Let’s review the information we have received from the geometry error in the current example file:

The error is occurring at the NSC group surface 2 (which happens to be the only NSC group in this file).  The object at which the error is detected is Object 2, the Cylinder Volume object which represents the core of the fiber.

As we try to diagnose the error, temporarily turn ON the Ignore Errors flag from the Errors menu of the NSC Editor.

Now, we already know that this error is due to the misplacement of ports, but let’s assume that we had no idea this was the case.  From the error message, we know that the error is occurring within your NSC group, so we can concentrate on the objects listed in the NSC Editor:  Component Group on Surface 2.  In addition (as we noted earlier), in a hybrid mode design, geometry errors are most often due to misplacement of the entry and/or exit ports.  Always first check the locations of these ports relative to the objects in your NSC group!

You may choose to draw the entry and exit ports by changing the “Draw Ports?” flag on the NSC surface in the LDE.  A flag of 0 will draw neither the entry or exit port.  A flag of 1 will draw just the entry port.  A flag of 2 will draw just the exit port and a flag of 3 will draw both.  Change the flag in the current example to 3. 

Update the 3D Layout and highlight the entry port by moving your cursor to the NSC surface in the LDE.  The entry port is currently co-located with the front surface of the fiber, which is an acceptable condition.  In general, it is desirable to offset both ports slightly from any object within the NSC group.

Since the entry port is not affecting the ray trace, let’s check the exit port location for possible flaws.