[Terry Capps]

The lines between the vertices define separate surfaces. AC3D frequently represents surfaces with complex shapes as a collection of rectangles and triangles. Boolean operations typically produce lots of triangles. You may be able to combine some of these surfaces if they lie in the same plane although sometimes it is easier to select all the surfaces (if they lie in the same plane) and do a "surface - delete surface only". Then select the vertices, around the periphery of the surfaces, in a counter-clockwise (or clockwise) order and then do a Vertex, Create Ordered Surface. This will work for some shapes, but won't for very complex shapes like all the way around a hole. You can still use the technique, but may have to settle for two or three surfaces instead of just one.