Ask HN: How is the light handled in the Monument Valley games?

I really like the design of the Monument Valley games [1], and it seems a big part of it has to deal with the way light and shadows are handled in the 3D scenes. To be more specific: * the light is really homogeneous (no variations of intensity) anywhere on the scene * there are no hard shadows, but really soft ones * the colors are vivid and bright What are the techniques that allow that kind of lightning? [1] https://www.google.com/search?q=monument+valley+game&oq=monument+valley+game&tbm=isch