Help for PERSPEC

PURPOSE      
             
    "perspec" converts 3-D IBIS graphics-1 files into a true 2-D perspective
3-D IBIS graphics-1 file.

OPERATION

    Perspec allows the user to manipulate the vertices in an IBIS-1 3-D graphics
file. When a graphics file is constructed the vertices are in a specific coordinate
system. Program PLTGRAF can be used to plot the object in whatever coordinates
given in the list. Perspec then allows the IBIS-1 graphics file coordinate system
to be modified. It also allows the user to adjust the origin and distance as well
as the angular relationships.


PARAMETERS

    INP and OUT are the names of the input and output IBIS files respectively,

    ELEV and AZIMUTH are the angles. 

    ORIGIN is the location of the origin of the perspective. Not the origin
    of the axes.

    DISTANCE is the location of the observer away from the ORIGIN

    ZSCALE allows the Z-AXIS to be scaled differently from the X- and Y-AXES.

    DATAFORM is how to show the X-, Y- and Z-axes. Normally, X and Y are horizontal
and Z is vertical.   

IBIS GRAPHICS-1 FILES

    IBIS graphics-1 files are a way to store 2-dimensional or 3-dimensional
polygonal objects in a file. The file contains a list of the successive vertices
of the polygons. When the list contains a line of all zeroes then it terminates
that face of the polygon. In the view of a drawing program it would be a
"pen-up" command. 

    With the advent of the IBIS-2 format graphics-1 files are deprecated.
In the new IBIS-2 format graphics-1 can replace that format via an index
column. In the IBIS-2 context each row is associated with a single vertex,
and the row order in a column determines the sequence of plotting the
vertices. A pen-up type command would involve a change of the value in
the index column. 


 
EXECUTION    
             
Examples:    
             
perspec inp.gr1 out.gr1 ELEV=30 AZIMUTH=135 DISTANCE=200

perspec inp.gr1 out.gr1 ELEV=30 AZIMUTH=135 DISTANCE=200  ZSCALE=10  ORIGIN=(100,100,10)


Code extracted from PLOT3D

Original Programmer:    Ray Bambery , 10 Feb 2013            
             
Cognizant Programmer:   Ray Bambery