Dave has finally release V2 of Knotmaker here http://daveroot.co.cc/KnotMaker/
It is a massive improvement on the old FCB utility and even has the option of creating custom 'ropes', but for me it is the ease with which we can now create a knot using the 'Direct Draw' method - simply click the faces of the square you want to connect with cord and the program sorts out which tile to use, also, we can just sketch the knot without worrying about over under etc, then go along afterwards and move the cords up or down, so they appear above or below other cords - you can even have as many as four cords crossing in the same square ! !
Personally I find the facility to move cords up or down is very helpful in thinking about new configurations of the same 'structure'.
Have fun, but if you discover interesting uses, please post them here and I will let Dave know what folk think of his work.