- The positions of A, B, C, and X can be defined as a rigid body. In other words, the relative positions and orientations between these points do not change from frame to frame (no stretching, no scaling, etc.).
- Points A, B, and C are not colinear.

- Use the points A, B, and C in the first frame to define a plane in the fixed frame F.
- Define a reference frame I, with the origin on the plane. Two axes span the plane with the other normal to it. For example, set point A as the origin, the x-axis parallel to the vector between points A and B, and use the right-hand rule to define the rest of the axes.
- Define the position of point X in the reference frame I. Because the relative positions between A, B, C, and X do not change, this position does not change even as positions of points A, B, and C change in the fixed frame F from frame to frame.
- In the second frame, find the new plane defined by the new positions of points A, B, and C.
- Transform the known position of point X in the reference frame I into the fixed frame F using the position and orientation of the plane defined in the second frame.
- Steps 4 and 5 can be used to find the position of point X in the fixed frame F for any frame after the first.

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