Here’s a more in-depth explanation by Rodeo FX about the specific work on this reel, created under the project’s vfx supervisor Joe Bauer:
For the nighttime sea battle, Rodeo created various simulations and cg environments, including a cg ocean and cg background ships, and extended parts of Yara’s ship, redressed it in cg and added extensions, as well as extending the Silence set piece to create a whole ship. Our team also augmented the practical fire in the plates, enhancing the foreground on-set fire with cg or comped fire elements in the background.
For the wall’s dramatic collapse, Rodeo scored the wall to break it apart in multiple shots to cover its extensive size. The team separated the wall in three parts: the closest area, which was destroyed in hi-res, the middle section, that remained standing in hi-res, and the farthest section in low-res as a base for digital matte paintings.
Rodeo received a previs referencing the timing and size of the collapse, and the studio layered effects on top of that. The team added secondary debris, smoke, and interactive fire when the fire hits the wall. For the actual collapse of the wall, Rodeo created debris, powdered snow, and water splashes as the ice falls into the sea. Real fire elements were provided and color graded to become the ice dragon’s destructive blue breath.