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In order to correctly drive corrective shape keys from a freely rotating organic joint it is very often found necessary to decompose the rotation into separate bending and twisting motions. This type of decomposition cannot be reproduced by any Euler order or a single quaternion. Instead this is done by using a helper bone with a Damped Track constraint aimed at the tail of the control to pick up the bending, and its helper child with Copy Transforms to separate the twist. Requiring two additional bones to drive a shape key or a correction bone seems inconvenient, so this implements the necessary math as new options in the recently introduced Rotation Mode dropdown of the Transform Channel driver variable type. The data is also accessible as a Transformation constraint input. The output is in the form of Quaternion-derived 'pseudo-angles', which for `Swing and Y Twist` would represent the following: * W: true bend angle, independent of bend direction. * Y: true twist angle. * X, Z: pseudo-angles representing the proportion of bending around X/Z. Reviewers: brecht Differential Revision: https://developer.blender.org/D5651
.. Keep this document short & concise, linking to external resources instead of including content in-line. See 'release/text/readme.html' for the end user read-me. Blender ======= Blender is the free and open source 3D creation suite. It supports the entirety of the 3D pipeline-modeling, rigging, animation, simulation, rendering, compositing, motion tracking and video editing. .. figure:: https://code.blender.org/wp-content/uploads/2018/12/springrg.jpg :scale: 50 % :align: center Project Pages ------------- - `Main Website <http://www.blender.org>`__ - `Reference Manual <https://docs.blender.org/manual/en/latest/index.html>`__ - `User Community <https://www.blender.org/community/>`__ Development ----------- - `Build Instructions <https://wiki.blender.org/wiki/Building_Blender>`__ - `Code Review & Bug Tracker <https://developer.blender.org>`__ - `Developer Forum <https://devtalk.blender.org>`__ - `Developer Documentation <https://wiki.blender.org>`__ License ------- Blender as a whole is licensed under the GNU Public License, Version 3. Individual files may have a different, but compatible license. See `blender.org/about/license <https://www.blender.org/about/license>`__ for details.