Abstract: We present a technique for automating the construction of Celtic knotwork and decorations similar to those in illuminated manuscripts such as the Lindisfarne Gospels. Our method eliminates restrictions imposed by previous methods which limited the class of knots that could be produced correctly by introducing new methods for smoothing and orienting threads. Additionally, we present techniques for interweaving and attaching images to the knotwork and techniques to encapsulate knot patterns to simplify the design process. Finally we show how to use such knotwork in 3D and demonstrate a variety of applications including artwork and transforming the designs into 3D models for fabrication.