Fairly simple project for creating 3D platforms from 2D grid. This can be used to providing in game level editing function for including custom levels in game. You can also save the custom created levels in json file and then later load it in run time.
You can see the proper implementation of this concept in the following project: https://connect.unity.com/p/591d21cb32b306002a8d604f
Link to project files: https://bitbucket.org/enigmacoders/ingameleveleditor/src