Invision is great for prototyping a general work flow, how the user moves from screen to screen, but it's not designed around building individual interactions.

Invision is great for prototyping a general work flow, how the user moves from screen to screen, but it's not designed around building individual interactions. You upload a bunch of screenshots and create clickable areas that link to another screenshots with some basic transitions. Origami is designed around building out individual interactions and transitions.