Parabola (conic curves in 2D) problems

[Michael777]

Hello everybody,

I am trying to create a set of parabolas going through some points. My need is to know if in a plane (2D) three points determine uniquely an analytical curve (parabola, circle, hyperbola etc.). My Analytical Geometry knowledge is kind of rusty.

I don

 

[donha]

You need 3 points and two angles to define the parabola as well as RHO. So, 3 points is correct, if you are allowed to specify the angles and RHO seperately. Two points are required to define a circle and 3 points are required to define an arc.

 

[Mloew]

Three points are required for a circle (or arc) unless the radius is known.



Best regards,



Matthew

 

[STUARTF]

How do I construct a conic by just using three defined points without having a RHO input?

 

[jeff4136]

Place a sketcher point on the curve (it should
latch on with a coincident constraint) and dimension
or constrain it to a projected reference.