Exploring the Subterranean Environments of Silo: Part I

Almost all of the action takes place within this underground silo, where 10,000 inhabitants have no recollection of any human history, including the inception of the silo itself 140 years before. The series follows protagonist Juliette who starts to ask questions about the ‘Before Times’; a crime that carries a sentence of being forced to leave the silo and go out into the poisonous atmosphere.

Helping to create this industrial subterranean environment, which carries so much of the story, was Outpost’s team led by VFX Supervisor, Ian Fellows (Bob Marley: One Love, Bridgerton). We spoke to Ian about his experience on the show, and how he and the team went about creating such vast environments and large-scale assets.

“As a fan of the books, I knew that world-building was going to play a huge role in our work on this post-apocalyptic story,” says Fellows. “We were really excited to be a part of the team that brought this well-loved sci-fi story to life.

 “While the season is almost exclusively set in one location – a 147-storey underground silo – our work was varied, requiring sculpting, hard-surface modelling, asset construction, DMP, and teams of compositors and lighters to bring it all together.” 

This two-part series will go deep behind the scenes of the two key areas that Outpost were responsible for. These environments were both at the very bottom of the silo: the generator room and the hidden space below it known as ‘the void’. “These were two very distinct environments,” Fellows continues. “One is a functional environment equipped with the generator that powers the whole silo; it’s a relatively small area, noisy and busy with people. The other is the void that holds the excavating machine that was used to bore the silo itself. This environment is vast, dark, quiet; its discovery is a pivotal story point.

“Bringing these two very different environments to life meant taking different approaches for each,” Ian continues.

The Void: A relic of the past 

The void environment sits below the generator room, hiding the machine that was used to bore the silo and, with it, long forgotten truths about the ‘Before Times’. 

When it came to creating this environment, the Outpost team received plate footage of the actors talking on a small practical platform. The rest of the environment – including the excavator asset – was up to the team to build.

“The void was such a big environment – around 550 feet in diameter – and the sequences involved a lot of sweeping, dynamic camera moves to really show off the space, so our initial questions were how are we going to make this space work over a number of shots,” explains Fellows.

Production VFX Supervisor, Daniel Rauchwerger, provided Outpost with references of old abandoned buildings and derelict spaces, paying close attention to how scale was portrayed in these kinds of environments. The client also shared early concept imagery of the basic structure and layout of the excavator machine. Outpost Art Director, Steve Molloy, then built upon these to give the excavator machine the show’s unique dilapidated, post-apocalyptic look, and to ensure it worked from a practical point of view.

“From the initial concepts we knew there was going to be a central drilling column and that there were going to be arms with drilling heads attached with a frame around the circumference,” Fellows continues, “but as we were laying it out in the environment the space didn’t feel big enough and so we had to break apart a lot of the geometry to make it take up more space and feel the right size.”

For Fellows and the rest of the team, selling the scale was a creative challenge that was present throughout all of Outpost’s shots within this environment: “The audience follows Juliette through such a journey in this environment, starting at the top of the void, travelling down to the very bottom. This meant that we had to nail the scale and perspective of the space from above, from the mid-level, and from below.”

To help with this, the team took a methodical approach to the environment and asset creation to ensure it had the most impact across the sequences: “We wanted to stay away from having a separate shot layout for each shot – that would have opened us up to continuity issues and would have been really time consuming.”

“Instead, we spent time looking across the big hero shots to identify what angles and which parts of the excavator and environment would be seen the most, and how much different angles would expose the asset, and we spent time optimising the scene and model for that.

“We built a singular asset with a rig that enabled us to manipulate it shot by shot if necessary, for example the spider arms and drill heads could be moved around, but ultimately it was the one model underneath that we deployed during the layout process.

“This gave us greater control over the final look of the asset, while making it work compositionally from as many different viewpoints as possible without having to go in and cheat every shot.”

With such a vast environment, lighting was a huge undertaking and integral to achieving the required look and feel of the series. “Because we’re deep underground, you get these little pockets of light here and there which reinforce the environment’s size. To add to the sense of depth, we silhouetted shapes that half-appear out of the gloom – we found that sometimes less is more in that respect and silhouettes gave us those impactful shapes that make you understand the sheer vastness of the environment,” Fellows recalls.

In a sequence which perhaps most reveals the environment’s size and emptiness, we see Juliette hanging from a rope in the void, having descended in a bid to reach the bottom.

“They shot her going over the edge on a set they had built, then when she’s descending and then hanging there, that was shot in a bluescreen studio.

“In the very last shot of episode two, Juliette has fallen down the rope and is hanging above the water at the bottom of the void. The camera slowly pulls out to reveal the space around her, and it was our job to make this space feel imposing. We took over the camera in this instance so we could move further back than they had been able to in the studio, revealing more of the space and allowing us to do what we wanted to do creatively.”

Episode three then opens with the camera going down the void through the drill heads to find Juliette where we left her, hanging above the water. “This was shot from an angle but with a static camera,” explains Fellows, “so we had to reconcile the end point of that angle and then extrapolate that into a much bigger camera move. This involved projecting her and rebuilding the rope and adding a subtle swinging motion. There were a number of challenges in those shots.”

The team also sculpted the organic walls of the void using mines and quarries as references. The walls were seen up close when the actors are going up the ladders, and further away for establishing shots. Again, the 3D team had to optimise the walls for all of the different camera angles.

Come back soon for part two, where Ian will detail the teams’ work on the Generator Room; an environment that presented many different creative challenges.

Stream all episodes of season 1 of Silo now.