[abenedik]

By json you probably mean glTF file format that use json to define the scene (and can also use some additional binary for meshes and other binary data).

You can import the 3D scene by Ab3d.Reader3ds and then use AssimpExporter to export the scene to glTF format (see the same with the same name in Ab3d.PowerToys samples project).

If you want some other kind of json, then you will need to write an exporter by yourself.