Contour Rig Tools
7.4#3 in 3d rigging softwareFrom $40 a monthFree planAPILinuxmacOSWindows
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It is intended for Maya riggers and technical directors working on animation production, as well as animators using existing Contour rigs. Check the stated Maya-version exclusions and license requirements against your workflow.
Houdini suits 3D artists and technical teams working in areas such as film, games, motion graphics, or synthetic data. Apprentice is an option for non-commercial learning and personal projects, with render limits to consider.