John VanSickle wrote:
> 
> Sebastian Strand wrote:
> >
> > Hi,
> >
> > I'm making a macro that involves a bezier_spline prism. What I need to know
> > is how I should place the control points of a bezier spline to make it
> > resemble a quarter circle as closely as possible.
> >
> > Just to clarify, this is how they points are placed:
> > O-------o
> >
> >              o
> >              |
> >              |
> >              |
> >              O
> >
> > Big O's are endpoints, small o's control points. If I place the control
> > points halfway to the corner I come pretty close to a circle, but I hope
> > there is a more mathematical way to do it, I'm not very fond of guessing :)
> 
> There is.  If r is the radius of the quarter circle, then the distance from
> the little-o control points to its big-O control point will be:
> 
>   4/3*(sqrt(2)-1) * r
> 
> The spline will be an exact quarter circle.  Your spline might look like:
> 
> Hope this helps,
> John
> --
> ICQ: 46085459
For my app, D-form (http://www.geocities.com/dkrota/D-form.html) I
searched for this formula but never found it.
Thanks!

Did you have also the formula for an half circle???

Regards

(---------------------------------------------------------------)
( Diego Krota   http://www.geocities.com/SiliconValley/Way/2419 )
(---------------------------------------------------------------)
(      Never do anything you wouldn't be caught dead doing      )
(---------------------------------------------------------------)

Post a reply to this message