Using Capsule Shadows on Large Objects in UE4
Capsule shadows are a great feature of Unreal Engine as they allow characters to cast soft shadows even with a game which relies on only static lighting.
The Last of Us 1 used this to great effect, as levels had a lot of areas which didn't receive dynamic lighting, and characters still felt grounded in the world using the capsule shadow technique (below).
Source: Arnage on the Unreal Engine 4 forums
The use of this does not have to be limited to characters however - the technique can be applied to other set pieces. The only caveat is that they have to be skeletal meshes, not static meshes.
Moving Set Pieces
Estranged is a statically lit game, with dynamic lights in some limited places. This is a stylistic and performance-driven decision, and means that large moving objects either need to be lit by a dynamic light, or need to use capsule shadows in order to look realistic.
I recently introduced a train sequence into Estranged, which the above mesh moves towards the player. The train needed a shadow as it looked completely out of place, so I created a second physics asset containing three very large capsules hanging a little below the mesh:
This grounded it in the world in a much more believable fashion (see the result in-game).
While the shadow is a little lumpy, it isn't that noticable and looks a lot better with than without the shadow.