Working at with a talented 3d team at Wolf and Crow I composited this shot in Nuke.

First was marrying a few different takes together. The practically crushed car and different plates of people running away.  I used stock footage elements to help bring them together and did some animation to extend the movement of actors who ran behind the original, un-crushed van.

Then  the CG robot and CG FX passes were brought into the plate.  I mixed in some more practical dust and smoke elements on top, and in the BG.  Also added a turbulent particle system in nuke to add to the chaos