Given three points in space, how do I get the changed angle of the plane over time?

As shown in the attached example file, I want to see the changed angle of the plane formed over time (frame) by forming a plane with three points given in space. What should I do? (I am a biginner so it might be hard to wirte code)

Thank you..

[Matt J]

I want to see the changed angle

What angle? The angle between the plane and another plane (if so, which plane)? Another line (if so, which line?

[규현 한]

I would like to see the Euler angle of the plane formed by three points according to each frame(time).

Answer 1

[Matt J]

Given 3 points in the plane P1,P2,P3.

u=normalize( P1(:)-P3(:) ,'n');
v=normalize( P2(:)-P3(:) ,'n');

w=cross(u,v);
u=cross(v,w);

R=[u,v,w]; %rotation matrix

angles = rot2taitbryan(R,'xyz')

[규현 한]

Thank you.