Building Chernarus: Where DayZ's World Came From

By Kotaku on at

by Rick Lane

Between Chernarus' northernmost town of Krasnostav and its largest airfield off to the West stand the ruins of Devil's Castle. It was founded in the 11th century by the ruling Kozlov Principate as the keystone in a network of fortresses designed to consolidate the dynasty's power in the newly founded region. It was two hundred years later, when this plan had failed, that the castle received its modern name. The bandit Jakub Čert (Czech for Devil) used it as his base of operations to pillage the surrounding countryside. When these raids ultimately brought an army to the walls, Jakub burned the keep rather than surrender it to his foe. It is said that on quiet nights the spirit of Duke Ivan Kozlov can be seen wandering the remnants of his masterwork, charred by the Devil.

In reality this legend dates back to somewhere between 2006 and 2009, when the Czech developer Bohemia Interactive was working on the military simulator ArmA II. But the fictional history of Chernarus - the 225 square kilometre landmass that is setting for both ArmA II and the zombie-survival sensation DayZ - ties into the design philosophy for the world itself.

Berezino Hospital

Berezino Hospital: The hospital at Berezino is a popular location as DayZ players scour it for supplies. In ArmA II  it cannot be entered, like many of the buildings in vanilla Chernarus.

Chernarus is a rugged yet verdant environment of rolling hills, dense forests and undulating meadows. Its valleys conceal quaint rural villages connected by barely perceptible dirt tracks, while its coastlines support sprawling industrial cities with wide roads and rail networks. It is picturesque in the sunlight and foreboding in the rain. But what is most striking about Chernarus isn’t so much the major landmarks as the little details, the way the tiniest bumps and dips in the terrain have been meticulously crafted. This is because Chernarus is modelled on the landscape in Bohemia Interactive’s own backyard, as the team believes even the most talented artists and programmers can't match the design power of time.

"You are basically taking the result of a process which was going on at that place for centuries," says Ivan Buchta, lead designer on ArmA II, and the man who has overseen Chernarus' development over the course of eight years. "Around 12th-13th Century people came there, and ever since they were developing the country, developing the landscape, changing it, leaving forests where they felled them, making clearings, meadows, fields, building villages on good spots."

Work on Chernarus began in 2006, and at that time plans for it were far more modest. Originally it was intended as an expansion area for the first ArmA game, a Baltic, post-Soviet accompaniment to ArmA's desert environment Sahrani. "I wasn't even working for Bohemia directly," Buchta explains. "I did some extra work for Australian department. Then Marek [Španěl] approached me. We were talking. I was interesting in using the GIs - Geoinformatic data, geographic data in the Real Virtuality engine."

Castle Keep

Castle Keep: View from the keep of Devil's Castle. Five years on from release, ArmA II can still cause the best PC's framerate to drop with the view distance set to maximum.

Looking to their native Czech countryside obviously provided easy access to an area which could be mapped with precision and detail, but Bohemia had exacting selection criteria. The area needed to be between 10x10 and 20x20 kilometres to get the sense of expansiveness Bohemia wanted. It also had to be square, because Bohemia's in-house graphics engine, Real Virtuality, does not support rectangular maps in its map-frame. Lastly, it Bohemia didn't want it be an island, because their last two games had been set on islands.  Instead, they wanted an area that was part of a larger landmass, with a mixture of coastal and mountainous borders.

In the end Buchta selected an area centred around the Czech village of Povrly, where the river Elbe turns sharply northward from its previously easterly flow, which Buchta describes as "A good basis for a natural coastline." More importantly, the terrain surrounding this area provided a lot of variation in a relatively compact space.

"In the normal Czech landscape you can often walk one kilometre, and you will walk just over one field," he says. "In this part, because of its volcanic origin, the terrain is very rugged with lots of local things like hills, small valleys, things like that. If you walk across one kilometre of Chernarus you will probably cross several roads, go through a forest, through a field, through a meadow, and maybe through a village or two. So it just felt perfect."

Chernogorsk Centre

Chernogorsk Centre: The centre of Chernogorsk, Chernarus' largest city, viewed from the huge factory which makes up a third of the city's urban sprawl.

Buchta created a digital elevation model of the area, and transformed it into a  contour representation using Geoinformatic software. This enabled him to preserve the landscape's bumps and troughs, but also edit those contours where he felt it was necessary. "I used this because we wanted to remove the outer bank of Elbe river to create the sea. I wanted to make some areas for villages flat, because at that time most household buildings [in Real Virtuality] were designed to be placed on flat surfaces or small slopes."

Once the basic terrain was mapped out, development focussed on filling Chernarus with things to see. This involved three groups of objects; forests and other natural landmarks, towns and cities, and the road network. Chernarus' extensive woodland was randomly or semi-randomly generated using tech Bohemia designed for its Real Virtuality engine. This amounted to somewhere between 700,000 and 800,000 objects. "It's like 50 or 40% of the real-life forest density," Buchta points out. "And I'm not even talking about the amount of forest species you need in the real-life forests of Chernarus. We really had to simplify it. But still, results were quite overwhelming."

Chernarus' road network was formed by combining the real-life road network of the area with some simple trial-and-error design. The cities and towns, meanwhile, were almost completely hand-crafted. The urban areas of Chernarus, such as the industrial Chernogorsk or the more commercial Elektrozavodsk, represented something of a problem for the team. The real-life towns in the Elbe valley were far too large to render in Real Virtuality without obliterating the game's framerate (generally buildings require a significantly greater polygon density to render convincingly than landscapes), yet they still wanted to make the cities feel expansive and complex.


Comparing the Chernarus map to the map of the area around the Czech town of Povrly, you can see where the river Elbe has been transformed into Chernarus' coastline.

"We are always trying to stick to some basic city-layout, with biggest houses and services in the middle, and some residential area around it, as well as some industry which is logically bound to the transportation - the railway or the road network," Buchta says. It was also important to ensure towns either had unique buildings in them or a running theme to aid the player during navigation.

When it was released with ArmA II in 2009, Chernarus was already a mightily impressive creation. But ArmA II was beset with performance issues, meaning many players were unable to fully enjoy the game and thus fully enjoy Chernarus. Furthermore, Bohemia's military simulators cater to very specific tastes. There was a risk Chernarus might be quickly forgotten about. But all that has now changed completely thanks to DayZ.

The importance of DayZ in Chernarus' story cannot be underestimated. It has added a further two million players to this moody eastern-bloc world, and the way the game is built means players are encouraged to explore it in its entirety, something that the ArmA games have never quite achieved. Most importantly though, DayZ's success means Chernarus is developing and evolving further.

Many of these additions are pipe-dreams of Buchta's from years before. "I remember that I always wanted some more buildings, for example, cars services, medical centres, police stations. I would say current DayZ developments still takes a lot from our original wishlists. Of course we had to process it a lot and see how to modernise it and how to answer specific needs of DayZ." In this case, Buchta's old designs and DayZ's needs tessellated nicely. DayZ players tend to cluster around the large coastal cities, where weapons and medical supplies are easily acquired. So in March, medical centres and police stations were added in some of the smaller towns in the centre, west and North of the map.


Zelenogorsk: On a personal note, my favourite Chernarus location is the town of Zelenogorsk and the surrounding, bowl-shaped valley.

Yet interestingly the cities are changing as well, taking advantage of the eight years of technological advancement to creep closer toward a truer representation of a large town. Cranes have appeared in the skyline above the eastern city of Berezino, a metaphor for the developer's own plans to build up these areas, and Chernogorsk saw the addition of a new tenement suburb, an area which had a powerful effect on Buchta. "As they are done using only a few types of objects, they are not so performance heavy. Essentially DayZ's map designer was able to style them as we seem them in the real-life location. When I saw it I was really amazed because I knew it from my childhood. I remembered it."

As of a few months ago, Buchta's involvement with the development of Chernarus ceased. The most recent and all future changes and additions to the map will be handled purely by the DayZ team. They'll be adding their own stories to Chernarus' already deep and rich history. It's rare that a videogame world gets such an extended lease of life like this, and Buchta is pleased to see how the DayZ team will further shape his original creation.

"It's like when you raise a kid, and give them basic education and then you release them to school, and now Chernarus is attending university. You can only witness it from the distance as a parent and you can hope for the best, and there are moments where you are pleased to see what you started becoming something greater."