Can VTK.js edit 3D files? The operations are: dragging to adjust the position of bones, and setting the position or angle of a certain bone separately.

Web vtk.js
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Yes, it’s doable. It’s a lot of manual user interaction handling. There are typically 2 approaches with VTK.js: you do the rendering of the interactive tools in 3D with VTK.js, or you convert the 3D world coordinate system into 2D screen coordinate system and delegate the rendering to SVG.
You have an example of delegation here.