How to arbitarily break a bezier.

[Con Neri]

Does anybody know of an alogorithm for splitting a known bezier curve into two
curves at an arbitary point? I have a reference to an algorithm but am unable
to get a copy here in OZ. The article is

"Arbitrary Subdivision of Bezier Curves," by B. A Barsky TR UCB/CSD 85/265
Comp Sci Div, University of California, Berkeley, November 1985.

If anyone can help, either by sending me a copy of the article or providing
some theory or pointing me to some easily available reference I would greatly
appreciate it.

Thanks in anticipation

CON NERI

All Graphic R+D e-mail: c...@allgfx.agi.oz.au
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[Peter Horan]

See Foley Van Dam Feiner & Hughes which is open before me at the very topic pp507-514

Given the control points P1, P2, P3, P4, a Bezier curve may be split in half by computing L1 - L4 and R1 - R4
where
L1 = P1
L2 = (P1 + P2)/2
H = (P2 + P3)/2
L3 = (L2 + H)/2
R2 = (H + R3)/2
L4 = R1 = (L3 + R2)/2
R3 = (P3 + P4)/2
R4 = P4

Draw a picture of it all. Its nice and easy.
--
Peter Horan
pe...@deakin.oz.au