Sketching knots is easy, but it might take a little practice.
Be sure you read the important items at the bottom of this page.
While sketching in the view window, the mouse buttons
are used in the following ways:
- Left Button
To place beads and cylinders under other beads
- Middle Button
To place beads and cylinders over other beads
- Right Button
To translate the sketching space.
To start sketching something, click on the 'Draw' button near
the top of the main
This will bring up the sketching control panel,
which is explained on this page.
When you first enter sketching mode, any knot or link that
was loaded in KnotPlot still remains, thus allowing you to
add to it.
If you would prefer to start a new knot, then click
on 'Delete All' near the top of the panel.
'Delete Bead' will delete the last bead drawn.
'Finish' will return you to the main control panel.
and 'Help' will bring up this HTML page.
Normally, what you've drawn is automatically centered after
sketching is finished.
If you don't want this to happen make sure
the 'clas' box is not selected.
You don't need to use these two buttons unless you
plan to draw links.
Link components can either be open or closed.
When you have finished drawing one component,
click on one of these two buttons to indicate
which type you want.
After that you can click on 'Finish' if you don't
want to sketch any more components or you can
Please note that at the moment open components
are not fully supported by all KnotPlot commands.
If something unexpected happens, use the
Clicking on the 'Flatten' button is exactly the same thing as
scale command with the first two
arguments equal to 1 and the last argument (the z-scaling) set to
the value of the 'Flatten' parameter.
Set the slider to 0 and click on 'Flatten' to project the knot
to the xy-plane.
KnotPlot usually does sketching in the 'Normal' mode,
where beads are automatically placed so the cylinders
they are connected to do not intersect other cylinders.
This sometimes fails, however, be sure to read the
important information below to get the best results.
Selecting 'Raise/lower' sketching will cause KnotPlot
to not autoplace the beads. Instead, beads will
be positioned high or low depending on whether the
middle or left mouse buttons are pressed.
'Trace' sketching mode is currently not implemented.
Selecting this option may have unexpected results.
Sometimes it's nice to have a background image
displayed while sketching.
To get one, first prepare a suitable image file
in the raw PGM format
with the name kp-backdrop.pgm (soon you'll be able
to use an arbitrary file).
The image should be about the same size as the
view window, or perhaps slightly smaller.
Then click on 'Load Backdrop' to load your image
in the background.
The 'Load Backdrop' button will change into
a 'Kill Backdrop' button which you can use to get
rid of the background.
Backdrop images are not properly implemented in KnotPlot.
If you delete beads you may have to kill and then reload
your backdrop to see the sketching area properly updated.
During normal sketching, KnotPlot
tries to be smart about where it places
beads, for example it attempts to place beads so that
cylinders are not closer than a certain distance.
This behaviour may seem a little annoying, but things should
be fine if you remember the following:
- If you're coming up to a crossing and you want to go
under it's a good idea to click with the left mouse
before and after the place where the crossing
- Similarly if you want to go over, click with the middle
mouse before and after the place where the crossing
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