Left Behind

Was not able to complete this on time but I can at least show this update to everyone. 

Adjusted moss, added broken head/tail-lights. Added dirty window. Added rain.

Second update. Added moss and dirt layer. Adjusted window opacity and roughness. Tweak displacement.

Here is my initial starting point. I use real life rust metal images which are then processed through Substance Alchemist to create the PBR material.  Then I used the 'clouds' brush to paint the metal rust material on the surface. No dirt or moss at this point yet.

Displacement is used to exaggerate the peeling paint and oxidised metal look.

Unreal Engine 4's ACES is used as a custom color profile to give it a softer natural look.