2D to 3D conversion (brightness->height)

I found a way to take a grayscale image and convert it to 3D for printing, and thought I'd share. The site 'shapeways' (dot com) sells 3D items from your own designs, but allows you to download the x3db file for free. The free app netfabb (basic, also free) will open x3db files, and allow you to export stl parts.

My daughter is a fan of bands like Avenged Sevenfold, so I'm making her a cell-phone case with the Deathbat image created this way. This is a small test print to make sure it was going to work the way I intended. As you can see, the wings are not quite right, but I can easily fix that and re-create the stl.