I’ve created a Blender plugin generates 3d beziers curves in elaborate “celtic” style knotwork, based off of a framework mesh. Tested with Blender 2.68a. It’s available on github.

Celtic Knots are a intricate decorative design found in Celtic and other cultures mosaics and manuscripts. The knots often include elaborate variations and unusual angles that the plugin does not attempt to create, so touching up the resulting path in blender may be necessary for some designs.

Refer to the tutorial for some instructions on how to use the plugin, and the gallery for some examples of what is possible.