Thought I would share this.You could easily use meshes from Knotplot and import them into Bryce and do an altitude render from top view. You could use this to make a displacement map to wrap around a cylinder, or elongated cube in UV Mapper Pro to make a Celtic knot-carved pillar or beam. Just a thought.  Here's a sample of an altitude render of a Knotplot mesh made with the celtic knot designer.