The procedure for constructing a circle by three points in 3D
Idea of ​​the algorithm taken from the publication of Alexey Ivanov
http://www.mapleprimes.com/posts/207697-Circle-In-3d-
The calculation algorithm
1. The three points are vertices of the triangle. Write three linear equations:
two equations of planes passing through the midpoints of the two sides of the triangle
perpendicular to these sides: f1 = 0, f3 = 0
and the equation of the plane which contains the triangle: f2 = 0.
2. Solve the system of equations and find the center of a circle with coordinates Cen xCen, ... zCen.
3. Find the circle radius R of the equation of a sphere with radius R and center at Cen
4. Construct a circle as the line of intersection of the sphere with the plane of the triangle (Draghilev method)

Okruzhnost'3.sm (55.35 KiB) downloaded 1092 time(s).

Modified the program


OkruzhnostMod.pdf (243.54 KiB) downloaded 731 time(s).
OkruzhnostMod.sm (67.93 KiB) downloaded 1043 time(s).

Changes:
1. Circle is constructed by matrix transformation, and not Draghilev Method
2. The normal to the surface passing through the given points is shown.

OkruzhnostMod3.sm (54.16 KiB) downloaded 1041 time(s).

Thanks Ber7, saved.

Hi, Jean, thanks for the support.