https://multigrain.texture.rocks/ 2026-05-25T07:57:58+00:00 https://multigrain.texture.rocks/ https://multigrain.texture.rocks/lib/exe/fetch.php?media=wiki:logo.png text/html 2019-02-21T06:27:49+00:00 Anonymous (anonymous@undisclosed.example.com) https://multigrain.texture.rocks/doku.php?id=advanced:2pi_or_not&rev=1550730469&do=diff 2π or not? Single-crystal diffraction calculations rely on g-vectors, U-matrices for defining grain orientation, and B-matrices for conversion between the Cartesian grain system and reciprocal space. In physics in particular, g-vectors Ghkl are defined as a perpendicular to the diffracting plane (hkl) with a norm of 2π/d text/html 2021-07-01T07:55:28+00:00 Anonymous (anonymous@undisclosed.example.com) https://multigrain.texture.rocks/doku.php?id=advanced:3d_rotations&rev=1625126128&do=diff 3D rotations 3D-rotations lie at the core multigrain crystallography, texture analysis, and many other topics in materials science. Typically, one describes the orientation of a crystal lattice by a set of rotations relative to an external reference frame. Unfortunately, there are many ways to do so! Do you want to rely on Euler angle triplets, in the what convention, axis–angle pairs, quaternions, Rodrigues–Frank vectors, rotation matrices, homochoric representations? What are the sign conve…