DRAWING AND VISUALIZING KNOTSYing-Qing Wu
Create a new knot.In the directory of ming, type the command ming to start the program. To draw a new knot, choose New from the File menu, or use the keyboard shortcut: Press the alt key and type n.
Click mouse button 1 to get a new vertex for the knot, and click button 2 to delete the last vertex. To move the new vertex, do not release button 1 after pressing it, and move the mouse around to move the vertex on the xy-plane (the view plane). To move the point along the z-axis, press button 1 and button 2 simultaneously, then move the mouse up or down. Knot can be opened or saved to a knot file using the File menu.
After making a knot, the program enters edit mode. Click the edit button on the control panel to exit/enter edit mode.
In edit mode, click the arrow box on the right hand side of the drawing area to make picking possible. Click button 1 on a vertex or an edge to highlight it. Button 2 is used to delete a highlighted vertex, or add a vertex to a highlighted edge. Moving a highlighted vertex around in the same way as when drawing a new knot. One can also use the wheels to turn the knot around, then move the vertex in the desired direction.
Visualization.The drawing window, the wheels, and the little pictured boxes on the right edge of the drawing area form the ``examiner viewer'' of Open Inventor. This viewer has some nice built-in functions, which is the main reason we used Open Inventor instead of Open GL.
Click the ``eye'' box will put the knot in a good view position. Click the ``hand'' box to enable moving the knot. One can then drag the knot around using the mouse buttons. Click the ``?'' box to see detailed help information about this viewer.
Ming can visualize 3-D knot picture in different forms. The thickness of the knot can be changed using the Size menu items, or the command e N. In non-edit mode one can use the Render menu to choose drawing the knot as arc segments, tubes, or cylinder-balls. Use Color menu to specify the color schedule, or bring up color editors for knot and background, respectively. See commands and menus for more details.