fxg: So where did you start with modeling Hogwarts?Vickery: Ultimately we were tasked with building this asset that was essentially seven miles from one end to the other, with a completely digital school in a completely pristine
state and a destroyed state. We weren’t sure how close we were going to get to any of it. But we had to prepare for it both in terms of the en
vironment and in building the asset. I think one of the cleverest things we did was that our lead environment artist – Piet
ro Ponti – was tasked with going to Scotland where they shot the mountains surrounding the school and capturing that data. He set up a three-camera rig, left, center and right. The cameras were all set up with remote trigger shutters. He went up in a helicopter and they would fly semi-circular flight paths around every
single mountain they needed to capture, at different heights.
Pietro plotted all these points out using Google Maps and Earth, so that before he went he was able to work out the best time of day depending on the time of year they were shooting, so that they got the best lighting for every mountain. The helicopter pilot was really great and also super-excited that Pietro had managed to do all of this GPS work. They just fed the co-ordinates into the helicopter nav system and just flew perfect positions all the way around the sides of thes
e mountains. It was an amazing little trick.
We got all of this information back at Double Negative, and used a piece of software called Photo-fit, which is a photogrammetry tool we used to re-create the mountains. Once we
had all the mountains, we worked closely with Stuart Craig, the production designer, and he created a collage of geome
try surrounding the school and we could put the mountains anywhere we wanted. The next tricky thing was actually just modeling the school. In the end we had a team of about 30 people working for two years building the school. It was fully pristine and brand new, but then also torn to pieces.
fxg: What about the detail on the stonework and Hogwarts building itself – where did reference for that come from?
Vickery: Real buildings. It was a combination of Stuart Craig’s amazing team which have literally done thousands of archite
ctural drawings of literally every single school building. You could re-create Hogwarts from these if you really, really wanted to. We had all these blueprints that went into the tiny details of each of the tiles of the gapping stones in the Great Hall, to the arched windows, and even profiles of hand rails that ran around the inside of the staircases. So that was the starting point, then Pietro and his team went to t
he actual filming locations that Stuart had used to design the school – Durham Cathedral, Edinburgh Castle, Winchester Cathedral and others – which we extensively photographed.
The actual physical textu
res were painted by hand, but when you look at real buildings you realize ther
e can be some really weird things going on in there. You’ll see there are even small trees growing out all over the place in the higher reaches of old cathedrals, coming out of old brickwork. And just the way that one face will be worn because that’s the predominant side the wind or sun is coming from, which fades things differently. And different buildings sag slightly too.
Stuart would come into Double Negative a number of times to review our work. His keen eye for detail was put to the test. He would scrutinize every little thing. We’d produce these renders that we thought were perfect – beautiful and photoreal renders that would match their courtyard perfectly. Stuart would look at it and go, ‘Ah, the mortar lines look a bit like they’re a bit too wide over there…’. And then when we started destroying the school, we started getting into what was inside the walls. He would say, ‘You can’t just break a wall and have three layers of bricks, because actually if they did that there would be a course of brick and then inside that there’d be a course of rubble, and behind it another course of brick.’ So we ended up getting a specification for how thick each wall around the school should be and what would be in the middle and on the outside. It was literally a masterclass in architecture.
fxg: When it did come time to destroy parts of Hogwarts, how did your model interact with some of Dneg’s destruction tools?
Vickery: Well we already have this great pipeline of tools, so that meant we could spend a lot of time doing the creative side of the work, rather than too much R&D, because it w
as already done. Essentially we took a fairly old-school approach to destroying Hogwarts – so if say a roof collapsed we would make 3,000 roof tiles and build the roof as a real object from Stuart Craig’s set plans, and then we would drop a canon ball on it or fire big forces at it and see what happens. Because we had built the entire school we could actually knock it down for real.
We’d also run these physical simulations on huge walls or rooftops or turrets and knocking them down and seeing what happened – that gave us a beautiful organic feel t
o the destruction as well. They would stop working somewhat if we needed to art direct the destruction, at which point we would go in and sculpt and model holes in the sides of walls. We also had areas of destruction that
had to match the real set, so we had to sometimes physically place planks of wood and beams and masonry detail, especially for the courtyard set.
fxg: How was the protective shield that goes over Hogwarts generated?
Vickery: Firstly, Tim Burke gave us a real free hand in the aesthetic and let us put some versions of that in front of him for ideas. So we had big creative input, and then that was taken on and driven by him. It also became a shared effort between 2D and 3D. Sometimes in visual effects, shots like this are driven by the 3D particle simulations, and then comp is doing the finishing touches. But in this instance, because it was such a creative concept, it came from a lot of different inputs.
Tanya Richard did a lot of concept work in the first instance, and then Alexander Seaman, our effects lead, put together some fantastic Houdini effects work, particles and cloth simulation and some straight-up texture painting. He handed it to 2D artist Christine Wong, who was a really creative compositor and defined the look of the shield in Nuke, also using a lot of the 3D tools in that software.
fxg: There was a lot of sharing of shots and assets between Soho vfx houses on this film, especially for Hogwarts. Can you talk about how the work moves between facilities?
Vickery: The amount of collaboration was pretty incredible. If I wanted something from MPC, I’d pick up the phone and ring Greg Butler, their VFX supe, and say, ‘Hey, are you working on this, can we have the stone knights?’ And he’d send that over in the afternoon. We weren’t really competing with each other, because when the work had been awarded, we all sat in the same room together. Tim Burke and Emma Norton (the overall VFX producer) would divide the work the way they thought best, and then let us sort out the details of interacting with each other. We’d have these meetings where we’d work out the easiest way to work on the shots and sometimes things shuffled back and forth between facilities.
Sometimes we’d do things like the backgrounds and they were relatively easy shots to share. It got more complicated sharing things with say MPC, who had done a lot of previs for the battle sequence. Their previs would be passed over to us to do the shots. Early on we shared our previs Hogwarts asset with them, and they built stone knights and viaduct elements that they gave to us. We also of course kept Tim and Emma and Warners in the loop.
reo.
er seat to avoid a gas bottle truck. As the two heroes launch into the air, Bumblebee continues to knock objects out of the way and protect Sam, before grabbing his screaming friend at the las
res were painted by hand, but when you look at real buildings you realize ther
o the destruction as well. They would stop working somewhat if we needed to art direct the destruction, at which point we would go in and sculpt and model holes in the sides of walls. We also had areas of destruction that 