Since Europa Universalis III, Paradox Development Studio’s grand strategy games have owed a debt to Prussian general Carl von Clausewitz, or at least his name. The Clausewitz engine has powered every internal Paradox Interactive game since 2007, but starting with upcoming grand strategy game Imperator: Rome, it’s getting a pretty significant upgrade. Yes, it’s also named after a Napoleonic era general: Antoine-Henri Jomini.

“Naming is the hardest thing in software,” jokes engine team lead John Wordsworth.

Jomini isn’t taking over, and Clausewitz isn’t going anywhere; the pair are two halves of the same engine. “Clausewitz is a bunch of code that you can use to make games,” says Wordsworth. “Theoretically, you could use it to make a city-builder, a strategy game, an FPS … not that it would give you any tools for that, but you could, theoretically.

“Jomini is specifically for the top-down, map-based games. The overall vision is to try and share tech across as many of our projects as possible, so we can make bigger games, better games, faster.”


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For pros and modders

Above: Imperator: Rome should be friendlier to modders thanks to the Jomini improvements.

Image Credit: Paradox Interactive

The most significant difference between the engine we’ve seen in the likes of Crusader Kings II or Stellaris and the new Clausewitz-Jomini alliance is the inclusion of proper tools, which will affect everyone, from those that design the games to those that mod them.

“Modders always ask us why we don’t give them the tools we use to make the games, but we don’t have any. People are the tools. That’s the biggest thing we’re changing. So we’ve got two tools engineers in our team, and we’re recruiting two more. Half of our team is going to be building tools, going forward.”

For the designers, the new tools mean that they can focus on what they’re good at, specialities like art or writing, instead of editing text files. This doesn’t mean that Imperator and future games won’t permit modders and developers to make big changes by dipping into the text files, just that coding will no longer be a barrier.

“Let’s imagine Stephen King or the world’s best 3D artist came to our door, looking for a job on a new game. We’d have to ask them: ‘Can you script? Can you edit text files with curly brackets?’ Now we don’t need to.”

In the World War II game Hearts of Iron IV, if artists want to make a small adjustment, they need to go into Photoshop, tweak some pixels on the map, fire up the game again and reload the map, see if the changes look good, go back into Photoshop. It’s a bit of a slog for the tiniest of adjustments. With the new tools, all these changes can take place while the game is running live. Artists can paint the map, essentially, and the see the impact of their tweaks instantly.

Wordsworth sees his role as empowering the designers and modders, whether they’re adding some mountains to the map or creating a custom UI for an overhaul mod. “Our games are often compared to Excel, so we’ve completely reworked the GUI system. Not only is it flashier, we’ve changed the way you can make new ones. Modders should be able to make super-fancy UIs without editing any code in the game. I think it comes down to that: We want to put as much power as we can into the hands of the people who are making content. They shouldn’t have to ask a coder for help.”

Changes under the hood

Above: This may look like a map from Europa Universallis, but the tech running Imperator: Rome is different.

Image Credit: Paradox Interactive

Paradox has only been providing hands-off demonstrations of Imperator, so a lot of the engine changes remain invisible, though the visual enhancements are clearly noticeable. The map itself is a striking representation of the world of antiquity, making its predecessors look drab in comparison. It’s bursting with tiny geographical details, as well as plenty of settlements that grow and change physically, while the Italian coast — only Italy is ready to be shown off at the moment — just screams “It’s time for a beach holiday.”

“We’ve completely rewritten the graphics rendering system,” Wordsworth explains. “So now we can use DirectX 11 features, and the way that the games interact with the graphics layer has gone up a generation. So the games are now able to have more advanced graphics features with less effort, which is super helpful for making the shiny screenshots for the showfloor.”

Audio has similarly been given attention. The team has switched to Firelight Technologies’ popular FMOD tool, which is a significant upgrade over the old — very basic — audio system.

“It was basically a jukebox,” Wordsworth admits. “You can play a sound with a line of script, and that’s it. Now our audio engineers have live audio editing features where it’s basically like an audio suite. They can connect to the game while it’s running, tweak all the levels, maybe add some bass, add a compressor to make the sound effects stand out more in the background. You’re going to want your headphones on when you play Imperator because it’s going to be a step ahead.”

Clausewitz’s latest evolution won’t be seen in Paradox’s previous titles because they’d be completely different games with different system requirements. The aim is still to keep future games accessible, however, even if you’re playing on a PC or laptop without too many bells or whistles. Aside from the 64-bit requirement, Imperator will be modular, letting you turn off a lot of the new features being introduced by the upgraded engine.

Working on Jomini has also provided Paradox with an opportunity to tackle performance. With so many AIs, end-game states, and options to consider, games can start to slow down. “In an FPS, in a boss battle, you know that this is as hard as it gets,” says Wordsworth. “There are five bad guys, two bosses, and all these bullets flying around, and you can just test that over and over until it works. In a strategy game, there’s an infinite number of end-game states, so you handpick the ones you’re going to try to optimize.”

Above: Hearts of Iron IV looks a bit like Imperator — at least at map level.

Image Credit: Paradox

In Hearts of Iron, Germany is always a popular nation, so Paradox can make assumptions about what the world is going to look like. But these are also games where Argentina can take over the world and, at any point, there are countless AIs trying to figure out where to send their units or what routes to take, out of a massive list of options.

“Hopefully what we’re going to see in our upcoming games is maybe the simulation won’t run faster, but the game will run smoother. We know that sometimes the game’s going to be in a state where you’ve got a thousand AIs and they’re struggling to figure out where to send their units because there are so many choices, and that’s going to take time. There’s no way to simulate a thousand AIs much quicker. OK, maybe you could make it a bit quicker, but you’re going to hit your limit. If we can keep the game drawing a 60fps even though it’s thinking in the background, then the user experience will be better.”

Heady anticipation

Wordsworth is excited by the new direction, saying that it shows how Paradox is now treating the tech as its own thing. It’s a long way from the pre-Clausewitz days of just copying and pasting code between games to see if it works. It seems appropriate, too, that a lot of changes have been driven by what modders want. The studio’s grand strategy games have long been platforms for creative amateur designers, many of whom ended up with jobs at Paradox.

“One thing I really want to push is that we’re working on all these tools, and unless someone from legal comes in with a big hammer and says I can’t, we’re really hoping to give these to all the modders. Instead of appreciating us from afar, you can get your hands dirty. See what we do, how we work, and have a go yourself.”

Imperator: Rome is due out in 2019.

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