Check out the details here: https://youtu.be/hfZjBOHbRVg
Blog post available here: http://blog.wolfire.com/2017/04/Overgrowth-Beta-3-video-changelog
Full change log is available here: https://docs.google.com/document/d/1qxZxbZaJh2KnjLk_ICC4PfC74Eoxcfbimx8uiqqrqjs