Extracted from Harry Potter Page to Screen: The Complete Filmmaking Journey.
For the final film, Stuart Craig, the man who had designed Hogwarts, would have to destroy it.
‘But, whether you’re building up or tearing down,’ Craig explains, ‘the profile still has to be strong. We’d spent years refining Hogwarts into a visually iconic structure. And so I had to redesign it as a ruined building. It couldn’t just be the original design knocked down a bit, with holes poked into it.’
‘The final standoff between Voldemort and Harry in the ruined courtyard in front of the school with what is essentially the sun rising behind them and the smoke seen through the walls is so emotionally effective,’ he says. ‘It was a big challenge, but a very enjoyable one.’
In true movie-making fashion, the battle and destruction of Hogwarts were scheduled to be filmed before any scenes that take place in the undamaged school. This meant that property master Barry Wilkinson and his team had to construct every single piece of debris littering the castle when it’s under siege and then remove it so that the set could be restored to its original setup.
For the destroyed version, Wilkinson explains, ‘It wasn’t just a case of bringing truckloads of rocks in and tipping them out. The materials had to be lightweight – we had actors falling on it, running in it, so we couldn’t have real jagged rocks.’
Each and every piece of rubble was therefore manufactured individually, out of soft polystyrene.
To get around the limitations of only having footage from the shoot on the destroyed Hogwarts set, the visual effects team had started construction a virtual version of the school in 2008.
‘Knowing what was to come in the last book, we took the plunge,’ says visual effects supervisor Tim Burke. ‘We scanned the model that had evolved since the first film. We textured every facet of the building, constructed interiors so that you could see through the windows, and then built a destroyed version of the school.
‘With only a completely practical Hogwarts to work with, we would have shot it and been tied down to what was on film. Instead, as David Yates continued to develop the flow and structure of the sequence, we were able to make changes quickly or visualise new concepts and ideas. We had this brilliant digital miniature with which we could do anything.’