Globe rotating manually via drag event, when mouse click event fires - transition begins. For transition backwards use double click on any country. In this example transition is based on interpolation between two projections and map always cut along antimeridian, it creates effect of unreelling/reelling.
For other variations of transition from Orthographic to Equirectangular and back check these examples:
This projected is licensed under the terms of the MIT license.
Modified http://d3js.org/d3.v3.min.js to a secure url
Modified http://d3js.org/topojson.v1.min.js to a secure url
Modified http://d3js.org/queue.v1.min.js to a secure url
https://d3js.org/d3.v3.min.js
https://d3js.org/topojson.v1.min.js
https://d3js.org/queue.v1.min.js