Unwarrented Error in Boolean Operations

[Thaeris]

This project is nothing particularly special or important, it is merely an exercise to say the least. However, the problem is somewhat troubling, as it makes absolutely no sense.

The "hilt" object of the sword (blade is hidden) is intended to have a cut-out (the small diamond-esque shape in the middle) in the center. The cut out itself is a separate object, as is proper. The hilt started as a line in one quadrant of the xy-plane and was afterwards mirrored about the respective x and y-planes; the shape was then extruded to a distance, etc, etc, etc.



Eventually, the surfaces were made single-sided and were also triangulated (for the most part) to ensure the object is symmetrical (no wierd distortion via quads). The object was closed and the original line was deleted. The cut-out was made in a similar fashion. Upon attempting a subtract operation, however, I get the message that the object is composed of some sort of phantom line or polyline (or something to that effect). In an attempt to alleviate this problem, I removed the original surface and rebuilt the original surface one poly at a time. Still the problem persists. What's going on? (I'm using AC3D version 6.4.30)



Here's the file to date if that helps:

broadsword.ac

-Thaeris