pub const RIGID_TOLERANCE: f64 = 1e-12; // 9.9999999999999998E-13f64Expand description
How far the columns of a transform’s linear part may stray from an orthonormal basis, in each dot product, and still be read as rigid.
A rotation assembled from unit axes or from sines and cosines is orthonormal to a few units in the last place; a matrix off by more than this carries a scale or shear that no rigid copy of the solid represents.