Apps similar to nijigenerate include Inochi Creator, which is open source with a free version. Other options are AnimeEffects and Live2D Cubism. In total there are three Animation Makers like nijigenerate for Mac, Windows and Linux.
Inochi creator is a framework for realtime 2D puppet animation. On this site you can find the reference implementation as well as the official tooling for creating and using Inochi2D puppets for VTubing.
Denmark
EU
AnimeEffects is a 2D keyframe animation tool based on deformation of polygon meshes. You can easily operate, quickly shape your idea, and remake at any time if you have changed your mind.
Japan
Live2D is the world's first drawing technology to enable 3D rendering of 2D images. This technology supports a variety of portable consoles and smartphones, and Live2D is already being utilized for games that take advantage of the unique characteristics of hand drawn artwork.
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