Name
bsp — B-spline visualization
Syntax
bsp [size] [q | cm | cm2] [lin] [sav] [nst] [col] ; # draw b-spline
Description
Draw a b-spline curve close to the points in active workspace. The curve will not interpolate the input points, but follows the control polygon that goes between the input points which are the knot points in the curve.
Arguments
No arguments. Draw cubic b-spline in tube mode through input points.
size
Specify size of b-spline thickness either in tube or line mode.
q
Draw quadratic b-spline through input points.
cm
Draw cubic bspline and use the coeffisient matrix.
cm2
Draw quadratic bspline and use the coeffisient matrix.
lin
Draw in line mode (default is tube).
sav
Save the b-spline curve as a dataset in active.
nst number
Number of steps between the knot points in the curve.
col
Color shift for each cell.
Examples
Ex.1: Drawing a b-spline curve
# Digitize points and draw a b-spline
rcd ;# digitize 5 points
u ;# stop digitizing
poi ;# display points
pol ;# display line polygons
bsp ;# draw a b-spline
The above example produces this image.
B-spline curve with the control polygon