A general equation is derived for x‐ray diffractors with arbitrary toroidally curved surface and planes when used with a point source. This equation, which gives the locus of points on a curved diffractor’s surface for a given deviation from the Bragg angle, is shown to yield the appropriate equations for all of the crystal diffractor geometries that were previously discussed by Wittry and Sun [J. Appl. Phys.67, 1633 (1990)]. Two examples are given of the use of the general equation to design diffractors with improved collection solid angle over a range of Bragg angles. The x‐ray collection solid angle and focusing properties of these two examples are given.