02-11-2020, 03:43 PM

Hello,

I have some problems when trying to draw a 3D arc from 3 known points.

I've calculated the center of the circle and its radius.

Then, from the center and from 2 of the known points I've created 2 vectors OA and OB, from which I found the normal to the circle's plane by using the cross product of the 2 vectors, OA x OB.

The problem is that depending on which of the 3 known points I use as A and B (the normal will differ in magnitude but still have the same direction as it is perpendicular to the circle's plane by definition) the arc is drawn differently, not only because the direction of the plane, but also it seems to interfere somehow with the start and end angles.

Can you please explain how arc.CircleNormal is defined exactly?

How start and end angles are defined? (when is one point start and one end and not the other way around?)

And is zeroAngleDirection needed, what is its default option and its definition?

Thank you,

I have some problems when trying to draw a 3D arc from 3 known points.

I've calculated the center of the circle and its radius.

Then, from the center and from 2 of the known points I've created 2 vectors OA and OB, from which I found the normal to the circle's plane by using the cross product of the 2 vectors, OA x OB.

The problem is that depending on which of the 3 known points I use as A and B (the normal will differ in magnitude but still have the same direction as it is perpendicular to the circle's plane by definition) the arc is drawn differently, not only because the direction of the plane, but also it seems to interfere somehow with the start and end angles.

Can you please explain how arc.CircleNormal is defined exactly?

How start and end angles are defined? (when is one point start and one end and not the other way around?)

And is zeroAngleDirection needed, what is its default option and its definition?

Thank you,