Problem
Converting a given 3D model (a .obj file) to JSON format
Solution
Three js has its own converter now
requirements
The converted location in source code
https://github.com/mrdoob/three.js/tree/dev/utils/converters
So if you just downloaded three.js you should goto <your threejs root folder >/utils/converters to find the converter.
now in the command lin
cd <your threejs root folder >/utils/converters
node
obj2three.js <path to your model or .obj file>
Now a JSON file will be created in the folder you are in. You can use this with your JS code. Have . fun