CS335
Fall, 2008
Homework 8 (20 points)
Due: November 20, 2008 (Thursday)

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1. (Curves)
   A uniform cubic B-spline curve defined by 12 control points Pi,
   0 <= i <= 11, has 9 segments. How is the third segment of this
   curve defiend?  (5 points)

   Solution:
   The third segment is defined by control points P0, P1,
   P2 and P3. See the following figure for an illustration.

2. (curves)
   In the above uniform cubic B-spline curve, if we move control point
   P5 to a new localtion, how many segments would be affected?
   which segments?  (5 points)

   Solution:
   P5 is used in the definition of segments C3, C4, C5 and C6, but not
   the other segments. Therefore these four segments are the only segments
   that will be affected. See the following figure for an illustration.

3. (Clipping)
   Why is clipping necessary? What would happen if clipping is
   not performed or not performed properly?    (10 points)

   Solution:
   Clipping is necessary because, otherwise, we would get wrap-around
   effect which is caused by internal register overflow.
  

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Put you solution set in a text file  and send the text file to the
grader (xuwei.liang@uky.edu) before midnight of the due day.

           CS535 (Fall 2008)
           Solution of Homework 8
           Due: 11/20/08
           Name: xxxxxx xxxxxx