Originally Posted by
eelamb
Dan, Dan, and Dick have given you the best way to make the flutes. Making it outside designer gives you something like what is shown in the image below. Although setting zero depth around this pattern would work, carving this pattern or carving the pattern created using the 3d suite would take forever on a 36" flute using raster. It is best to use one of the methods mentioned by the two Dan's and dick.
Edit: If I were to do what you want, I would do it with a hand router, and guides. Much faster, and easier.