I would like to know is it possible to use 2 quadratic bezier curves

to model a cubic bezier curve?

Thanks

- Olumide

I would like to know is it possible to use 2 quadratic bezier curves

to model a cubic bezier curve?

Thanks

- Olumide

Of course not. Or sure. It depends what you mean by "model".Quote:>I would like to know is it possible to use 2 quadratic bezier curves

>to model a cubic bezier curve?

A quadratic is always planar. A cubic can twist through space, like

(t,t^2,t^3)

which in Bezier form for t IN [0,1] has control points

(0,0,0) (1/3,0,0) (2/3,1/3,0) (1,1,1)

Two planar quadratics cannot possibly match that.

On the other hand, you can certainly blend two quadratics by linear

interpolation to produce a cubic; and you can always try approximating

just as you would with line segments. So a more liberal meaning of

"model" yields a yes.

I dont know how the math goes, but I once found this:Quote:>I would like to know is it possible to use 2 quadratic bezier curves

>to model a cubic bezier curve?

http://www.openswf.org/code/cubic2quadratic.cpp

So, it's at least possible to fake/approximate it.

--memon

uow3W uow3w~/6Jo'3p15u1'mmm

1. How to Construct a NURBS curve from several (Cubic) Bezier Curves (joined end-on-end)

I have a series of Bezier Curves with Control vertices:

P0, P1, P2, P3

P3, P4, P5, P6

P6, P7, P8, P9

...

...

P(n), P(n+1), P(n+1), P(n+3)

P(n+3), P(n+4), P(n+5), P(n+6)

....

I would like to construct a single NURBS curve that "interpolates" all

points generated by all the above bezier curves?

I assume this involves lookind for De-Boor points?

Is there any standard way of doing this? (Generating De-Boor points

from Bezier Points that is.)

Thanks

- Olumide

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