"The script gave a certain amount of detail in terms of what we see," he added, "and then my discussions with Dan and David illuminated it even further, but a large part it was me sitting down with a storyboard artist and trying to determine how to best represent this epic event. We’d think about what to focus on and which angles would create the most drama and tension and how to convey such a huge moment. It was weeks and weeks, month maybe, of conceptualizing and drawing and figuring out, and then working with the visual effects department in terms of creating animatics."

"The execution is the next thing," Podeswa continued. "Once you decide what’s going to be visual effects and what’s going to be practical and how to achieve everything, it becomes another thing. One thing that was very helpful too is that the VFX department has concept artists too and they work from the script and create paintings that are reflective of tone and mood of what the sequence should be. When you have a very effects-heavy sequence like that, they’ll do a series of about 10 paintings that contain elements of the sequence and they were very helpful in terms of what the sequence should feel like."

(via ign.com)