Each of the download options described below will, unless otherwise specified, reflect the current settings selected on the drawing page.


Outputs a colour Adobe Postscript/PDF document.


Outputs a 500x500 pixel Portable Network Graphics format file.


Outputs a black and white broken line Xy-pic diagram, suitable for inclusion in a LaTeX document.


The output file contains the coordinates of the flex point and crossings in the order of traversal around each component.


Outputs the povray version described below in a format suitable for usage in Knotplot.


The PovRay output is intended for use with the PovRay raytracing program. In order to use this PovRay scene, you must have the file spline.mcr saved in either a library directory that PovRay knows about (during the installation of PovRay, the location of each of the relevant directories is shown on the screen and written to the installation log file) or in the same directory as the .pov file. We use this package to extrude a tube along the bezier splines generated from the Knotilus data. Knotilus outputs a series of 2D Bezier splines. For each knot in the spline, we use the x and y co-ordinates of the knot but we adjust the z co-ordinate according to the following scheme. Overcrossings and undercrossings are given +10 and -10 for the z co-ordinate respectively. Flex points between two crossings are given the average of the z coordinates of the two adjacent crossings. We also use the Bezier control points generated by Knotilus: the two control points on either side of a crossing are given the z coordinate of the crossing, while the control point on either side of a flex point is projected vertically to lie on the cone generated by rotating the line segment from the flex point to the crossing on the same side of the flex point as the control point in question around a vertical axis through the flex point.

Some useful customizable settings are documented in the PovRay scene, but reading the Spline Macro File Tutorial will give you a good idea about what is possible. The pigment, normal and finishing settings for each the components of the links are each separate and we have made some choices that generally produce good diagrams but we invite you to have fun changing these settings. Furthermore, the radius of each component's tube is readily modified.

A good starting point (once PovRay has been installed on your machine) to process a povray file (in this example, the file is named link.pov) that has been created for you by Knotilus is provided by the command

povray +a0.9 +h768 +w1024 link.pov

Some nice colours: