The basic sketches, on which the 3D models were formed, were drawn according to the proper procedure for drawing Gothic tracery, so that both the sketches and the 3D models consist only of lines and circles. If you dislike geometry, you may also draw some segments using curves, but then your 3D model won’t fit the authentic rules of Gothic tracery design.
Both 3D models are only available as NURBS 3D models, but if you use polygonal mesh 3D graphics software, we recommend that you download the 2D patterns and draw the Gothic window tracery you want, or convert these NURBS 3D models into polygonal mesh models.