Rick Lane parachutes into the tech behind the spectacular Just Cause open-world sandbox games
When it was released back in 2010, Just Cause 2’s virtual island archipelago of Panau was one of the largest true-3D open worlds ever created. Its landscapes ranged from rugged mountain ranges to thick tropical jungles and even a sprawling metropolis.
It was a tremendous achievement in terms of environment design, and the game was fun to boot, so you might be surprised to learn that the developer wasn’t entirely satisfied with its work on Just Cause 2. ‘We felt limited by the way the landscapes were represented,’ says Linus Blomberg, co-founder and CTO of Avalanche Studios, developer of the Just Cause series. ‘In Just Cause 2, we used traditional height maps for terrain, like most other open-world games, but their two-dimensional nature negatively affects what kinds of landscapes you can express.’
In the five years since, Avalanche has been quietly working on multiple projects, culminating in two games launching this year within months of each other. One of them, the upcoming Just Cause 3, runs on an entirely new version of the developer’s eponymous engine, which includes a radically rethought method of sculpting 3D landscapes.
‘This new technology is what we internally refer to as “digital clay”,’ says Blomberg. ‘It’s an entirely new and groundbreaking landscape technology based on a volumetric data representation known as “scalar fields”. This technique is common in medical visualisation, for rendering volumetric data sets captured from CAT-scans.’
To give a basic summary of how volume rendering and scalar fields work, a scalar field assigns a single value to every point in a given space, which can either be a mathematical ‘real’ number or a physical quantity. It works differently from vectors, which use multiple numbers to calculate points in space – usually x and y values when referring to 3D graphics. Physical scalar fields have units of measurement associated with them, but they must be independent of the coordinate system used to describe them. As such, two observers using the same units of measurement will agree on the value of a scalar field at the same absolute point of space.
Scalar fields can be used to render 3D datasets as a highly accurate 2D projection. Where generating a traditional height map will provide a rugged mountain terrain, volume rendering using scalar fields can also account for terrain layers that would otherwise be obscured by those mountains. Examples include tunnels or cave networks running within those mountains, terrain that overhangs other terrain and so on.
‘The new landscape technology allows for more detailed and complex topography. The enormous size of the world is still there, but this makes the environments much more dense and interesting, and also in the smaller scale,’ says Blomberg. This more intricate landscape should also be noticeable from the air, which is important in a Just Cause game where the player spends a lot of time airborne.
Alongside large environments, the Avalanche engine is also known for its destructive capabilities, which have been expanded for Just Cause 3 in various ways. ‘Central to the gameplay of Just Cause 3 is what we like to call “chains of creative destruction,”’ says Blomberg. ‘Since everything is physics-based, you’re able to set up (and set off!) these domino effects, where one explosion causes another one to go off, which pushes another physicalised object off a ledge, creating another explosion, and … you get the idea.’
Complementing these chains are much larger destructible objects, including long concrete bridges that span plunging valleys, and speeding cargo trains that can be derailed. ‘Also, Just Cause 3 is exclusively for new-generation hardware, which enables us to crank up explosions and particle effects several steps above what was possible with Just Cause 2,’ Blomberg adds.
Elsewhere, Avalanche has adopted a physically-based approach to rendering, previously seen in games such as Metal Gear Solid V. This term essentially means lighting objects in a way that mimics the physics of light as accurately as possible, calculating how light reflects and scatters off objects, and how that secondary light illuminates other objects, resulting in much more realistic-looking materials.
In addition, the developer has taken a hard look at one of Just Cause 2’s biggest bugbears – vehicle physics. Most of Just Cause 2’s vehicles handled like a milk float on marbles, so Avalanche has built Just Cause 3’s vehicle simulation on the Havok physics engine. ‘Everything in the simulation is defined at very high detail, down to the gear ratios and traction of the wheels, and is carefully balanced for each individual vehicle. Some of the vehicle designers on our game come from an arcade racing background, which should give you some idea of what we’re shooting for,’ says Blomberg.
Just Cause 3 isn’t the only Avalanche-based game to release this year either. September also saw the launch of Mad Max, Avalanche’s tie-in game published by Warner Bros. Curiously, Mad Max employs the previous iteration of the Avalanche engine, and doesn’t employ the studio’s digital clay tech. The older engine ‘made more sense for that game as it’s based mainly on the ground,’ explains Blomberg, ‘and it meant we could use a wellproven tools pipeline, which enabled us to focus on the challenges of crafting a highly detailed and atmospheric wasteland.’
Consequently, the design of Mad Max was more about designer skill than technological prowess – creating different regions that felt unique but stuck to the ‘wasteland’ theme of dry, barren and deserted landscapes, while breaking up the horizon with regular landmarks such as beached ships and abandoned power stations, imbuing a sense of dynamism to a dying world through violent dust and lightning storms. ‘We’ve always worked a lot with weather effects in our games, and have great support in our engine for it. But in the end, to get to that level, it really comes down to a lot of hard work and great craftsmanship,’ says Blomberg.
That environmental craftsmanship is evident in Mad Max , and it will likely be up to a similar standard in Just Cause 3 too, aided by Avalanche’s upgraded engine. The question now is whether the sandbox experience will have progressed sufficiently to compete in a year where the openworld genre has made major strides forwards – most notably in The Witcher 3’s astonishingly characterful world, and Metal Gear Solid V’s beautifully layered stealth systems.
Blomberg is confident. ‘With Just Cause 3, we took the generational leap over to the new technology, with all of the risks that means,’ he says. ‘We felt the reward from that technology in the kind of vertical gameplay Just Cause 3 provides was too great not to pursue.’