Help for Banchoff Applets

Controlling Windows and Variables

Controlling the view of graphical windows:

• The Tools menu lets you select the operation performed by a mouse drag in the graphical window.  The options are Rotate (3D only), Translate, Zoom, and Point.
• In 2D windows, the View menu has a Zoom In and a Zoom out option. 
  
• For 3D windows, the View menu options include Default, Up X Axis, Down X Axis, Up Y axis, Down Y Axis, Up Z Axis, and Down Z Axis.  The default view is the "standard" view from textbooks, with the positive z axes going up, the positive y axis to the right, and the positive x axis coming out of the plane.  If the window is selected these views can be chosen with keyboard equivalents of space, x, X, y, Y, z, and Z, respectively.
• For 3D windows, the views of Up X Axis, Down Y Axis, and Up Z Axis, are worth noting since they put the effectively project onto the x-y, x-z, and y-z planes respectively.
• If scaling is not otherwise indicated, the drawn axis segments are of length one.

The Control Window and Kinds of Controls:

• Expressions can also be thought of as constants.  The applets often use expressions for parameters that the user can change.  If the value of an expression contains commas,  the expression is a vector with a specified number of places.
  
• Variables have three text boxes and a series of buttons that look like they belong on a vcr for forward, back, fast forward, and fast back.  The three text boxes give the minimum and  maximum values of the variable along with the number of step taken in between.  The  forward and back buttons move the variable one step up or down.  The "fast forward" and "fast back" buttons animate forward and animate back until the variable reaches the end of the range, or the button is pushed a second time.  The text box between the buttons allows you to type in the current value for the variable.  If you do this, remember to hit the return key to register the changed value.  If you type in the current value, it does not have to be within the given range of the variable.
  
• Intervals have the same three text boxes (min and max value, and number of steps) as variables, but without the buttons.  They are used as parameters for graphs.  Changing the number of steps will change the smoothness of the graph.
  
• Functions have input variables in their names.  You may want to see the page on available functions to see which functions the applet parser understands.
  
• Checkboxes allow graphical elements to be hidden to highlight different aspects of the demonstration.
  
• Readouts look like a pair of text boxes, but you can only change the left or input box.  This lets you recover numerical data.  The input of a readout can be a vector.