Are you exporting a 3D graphic to eps?
A mobius band might very well have many many many polygons in it or very few. So maybe a raster would be actually more faithful to the image in the end than a vector graphic.
When you export something 3D to a vector graphic, it'll export the entire thing into the vector graphic, not just the parts which are visible. So if you have a complicated 3D scene to render, but most of it isn't visible, you will want to cut that part out before exporting the result to a vector graphic. The exporter doesn't "flatten" out your 3D graphic by doing some kind of ray tracing. That probably would introduce too many possible issues.