Scratch

So you want us just to share formulas, not help? Because this is advanced topics. Normally, people will tell you different formulas cause it's here, but we are nice people.

All I know is it uses trig. Try download Paddle2See's Bezier Nose

Paddle2See wrote:

Yeah, the Bezier Nose isn't going to help much in this case....the Bezier curve I used there will pass through two end points with a given slope at each end, but they won't pass through a given point in the middle, which I think is what yambanshee is looking for.

I do have a curve that might work for you though.  My Perpetual Slinky project uses a parabola which it derives from three points.  Look at the stage script area, that is where the parabolas are derived and evaluated.  I also derive the slope of the curve, which you probably don't need.  Hope that helps!

http://scratch.mit.edu/projects/Paddle2See/151048

Oh, than you're right. I just noticed how it made a curve, which seemed like what he wan'ts, but I konw nothing about this XD

bigB wrote:

it depends what curve you want to fit through the points.  if you want a polynomial (eg quadratic, cubic, quartic etc) curve look up a method called lagranges method.  sorry but its not easy to explain online (you could also use newtons interpolating polyinomial but this is even more complex.  if you want to make a circle that goes through three points that is also possible but im afraid i cant remember the method.
  What type of curve do you need?

im trying to make a circul

A circle from three points (A,B,C) is not complicated, just tedious.
generate a line from A to B
find the midpoint and generate a second line with an inverse negative slope ( old slope 2 ->  new slope -1/2 )
do the same thing for B and C
find the intersection of the two lines, this only works if the slopes are not the same,
This intersection becomes the center of the circle.
radius is distance form center to any of the points.
 
beware of advice from a fool