Scatter3D

Scatter3D is one of Pablo's display functional units.  It takes as input
a two-dimensional array of (x, y, z) coordinate data and plots the values 
in a 3D scatterplot.   The location of points is determined by the magnitudes 
of each scalar point and also the "minimum" and "maximum" values kept for 
each dimension (x, y and z).  Scatter3D treats values outside the acceptable 
range as either minimal or maximal, accordingly, for each particular axis 
over which the point is out of range.  The minimum and maximum values 
may be set by the user during the configuration process.

Clicking the left mouse button with the cursor inside the scatterplot area
invokes a callback allowing arbitrary rotation of the plot -- allowing for
arbitrary views of the data.


Functional Unit Inputs:  2-dimensional array.    The first dimension must
			 be of size 3 corresponding to (X, Y, Z) coordinates.
			 For example a 3x10 array would contain 10 data
			 points.

Scatter3D attributes:

	XtNwidth	width (in pixels) of the widget drawing area
	XtNheight	height (in pixels) of the widget drawing area
	XtNbackground	color of the widget drawing area background
	XtNfont		font used to display text information (callback)
	XtNaxisXColor	color in which the X-axis line is drawn
	XtNaxisYColor	color in which the X-axis line is drawn
	XtNaxisZColor   color in which the X-axis line is drawn
	XtNaxisOColor   color in which the origin point is drawn
	XtNapplyLabelColor	color of the 'Apply' label field (callback)
	XtNcloseLabelColor	color of the 'Close' label field (callback)
	XtNresetLabelColor	color of the 'Reset' label field (callback)
	XtNbackingStore	string describing the backing store (Xmu) option:
		                valid non-default options are Always, 
				NotUseful and WhenMapped.
	XtNautoScale	set to TRUE if data is to be autoscaled within
				the plot area (min/max ignored)
	XtNminXValue	minimum value represented along the X-axis
	XtNmaxXValue    maximum value represented along the X-axis
	XtNminYValue    minimum value represented along the Y-axis
	XtNmaxYValue    maximum value represented along the Y-axis
	XtNminZValue    minimum value represented along the Z-axis
	XtNmaxZValue    maximum value represented along the Z-axis
	XtNmarkerSize   controls size of the points
