"Tinith " <email@example.com> wrote in message <firstname.lastname@example.org>... > Hi, i have a polygon (e.g: rectangle) where it has equally spaced points (co-ordinates are known) inside it. then i need to draw a curvature shape (e.g: clothoid cuve, ellipse) inside this polygon. what i want to achieve is to find the co-ordinates of the points which is covered by the curvature shape. - - - - - - - - - - If by "shape" you mean the region enclosed by a closed curve, then use the inequality available from the equation of that curve. For an ellipse with equation
A*x^2+B*x*y+C*y^2+D*x+E*y+F = 0
you would test your points with the inequality
sign(A)*(A*x^2+B*x*y+C*y^2+D*x+E*y+F) <= 0
With a clothoid curve (cornu or Euler spiral), which is not a closed curve, I have no idea what it would be that you want. It has no inside or outside, only points along an infinitely thin curve. What would you call its "shape"?