Naming things is really hard! I’m discovering the different geometric types of the library and just realized that the `Isometry`

type is what I was trying to define myself as extrinsic parameters of cameras. Except in theory it shouldn’t. Isometries are the elements of the Eclidean group also written `E(3)`

(in dim 3). While extrinsic parameters are parameters of rigid body motions, which are transformations of the Special Euclidean group `SE(3)`

. The tiny difference between `E(3)`

and `SE(3)`

is that isometries can contain reflexions (mirrors) which have determinant of (-1), while rigid body motions, which can be written as the combination of rotation and translation, all have determinant of (+1).

I guess the difference is subtle enough, and “isometry” much more common than “rigid body motion” or “Special Euclidean”, to have the tradoff in favor of keeping the current name. I was thinking that it was worth mentionning in the documentation though?