
 Curves, Introduction
 
 Smooth curves  are achieved  in QD3D  by  locating  points  that
 govern the shape of the curve (Bezier and B-spline curves).
 
 If any  of the  points on a curve are deleted (see 4.4 POINT DEL
 for details), then the curve is also deleted.
 
 When prompted  to select  a curve, the user does so by selecting
 any point defining the curve with the selection button.
 
 
 "CURVE ADD"
 
 This command  is used  to add  curves to  the screen.  The  user
 inputs the points to define the curve and QikDraw calculates and
 plots the curve. Two types of curve are supported, bezier and B-
 spline.
 
 Procedure
 .   Specify if adding a Bezier or B-spline.
 .   Specify the degree of the curve.
 .   Add points to define the curve as desired.
 
 
 "CURVE DEL"
 
 This command  allows the user to delete selected curves the same
 way as lines are deleted. HELP LINE for details.
 
 
 CURVE UNPAK"
 
 This command  is used  to UNPACK the curve. The user is prompted
 to select  the curve  by locating one of the points defining the
 curve (a  definition point).  QD3D then  unpacks the  curve into
 lines and points.
 
 
 "CURVE CHNG"
 
 A selected  curve can  be changed to reflect current definitions
 of pen  and layer  the same  as any  other element.


