Knots3D 1.4 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The most popular versions of the Knots3D 3.4 and 1.4. This free software is an intellectual property of Steven Abbott. Commonly, this program's installer has the following filename: Knots3D.exe. We recommend checking the downloaded files with any free antivirus. Knots3D lies within Photo & Graphics Tools, more precisely Viewers & Editors.
From the developer:
It has an AutoGrid feature that lets you create complex knots from a simple graphical template. The knot at the top of this page was done with this technique.
You create the knots in 2D then make them into 3D knots which you can rotate in 3D space. It can also output the knots in various 3D formats including VRML for viewing in browsers.
You may want to check out more software, such as XDCAM Viewer or EasyPic, which might be related to Knots3D.