How Wheel World's massive rolling landscapes were made possible with Houdini

Small indie dev teams needn't be limited in the scope of their projects. There are plenty of resources and tools to help realise large worlds, as in the case of Wheel World, a serene cycling adventure game set in a stunning cel-shaded semi-open world.

Wheel World is also a significant step up from developer Messhof's previous pixel art side-scrolling fighting game series Nidhogg, instead taking inspiration from open world games like The Legend of Zelda: Breath of the Wild and sports games like Motocross Madness and Lonely Mountains: Downhill.

But while the team is technically larger than before, that still amounts to about ten people, with just two artists at the moment. How can they manage to build the large biomes required for your rider to cycle around? By having a vital third member on the art team. Well, they're not a person but rather Houdini, a procedural generation art tool for 3D animation, used not only by AAA studios but also indies. (Houdini features on our list of the best 3D modelling software.)

"Even for a reasonably sized art team, I think building a city is quite daunting," says co-art director Dan Hunter. "For a small team like ours, it meant that I could create a tool that, for example, creates barriers like a wooden fence, and then I can give that to Mark [Essen, creative director] or other designers and they can specify the length and colour. Rather than me going, 'You need a fence that's 10 meters long,' you can just say, 'Here's a fence, build it three miles if you want," and then you build on that."

Not to be confused with generative AI, procedural generation relies on providing rules and parameters, which, in the case of building a town, could mean determining width and length of buildings and how far apart they are from each other, but which can also include some randomisation to add variation. (Read our Houdini tutorials for an idea of how this works.)

"I could have made a suite of 10 buildings, but it would have looked really generic," Hunter explains. "[With Houdini], I give it parameters that say extrude or make a building this high but then at that height maybe go two meters above that and two meters below that. Then almost anything you can think of that would be attached to a house I then add in, so it might have windows here but there's a 50% chance there's going to be a flower basket on the window, as well as doors picked from 20 selections of doors."

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There are still props that are built by hand, such as air-conditioning units and satellite dishes, but these are also objects that would be realistically identical, which Houdini can then add into the mix with instructions, such as ensuring it's always placed at least five metres off the ground or only on a rooftop.

Using procedural generation doesn't mean Wheel World is lacking in any artistic personality. Indeed, it's very committed to its cel-shaded comic book aesthetic not just in character models but in environments, such as the first main Italy-inspired biome Tramonto.

It's a style that had been established early by the game's original art director Abel Oroz (Rime, Arise), based on illustrative posters of Tour de France from the '50s, back when the game had been titled Ghost Bike. "His vision was really clear, it's a very European-looking game," Hunter says of his predecessor. "In some biomes we move away from that, but I think he really did capture that sense of a Tuscan world, so it was a real pleasure to work with him and replicate his artwork."

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To achieve that flat shade effect, he tells me that the game doesn't actually have any textures, instead everything is vertex painted, although the aesthetic also hides the detail of the models that have a deliberately wobbly appearance. "We don't have parallel lines, we don't have straight lines, so a building will kind of be wobbled. There is kind of a decent amount of polygons in those things, but that's just to create a kind of roundness and wobbliness to everything."

Another trick to maintain that hand-drawn feel or that it feels like "something you would do in Photoshop", is how the details are rendered based on your distance. "When you're up close, you can pick out individual trees in a forest, but if you look at that on a mountain across the other side of the map, you would just kind of see an outline of green and brown, and it becomes a bit more abstract,"

Hunter explains. "We were kind of very cognisant of it needing to look like the concept art, but it's also a 3D thing as well, so what does it look like going away from you or coming towards you? We spent a lot of time figuring this stuff out."

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Wheel World is launching summer 2025 on PC, PS5, and Xbox Series X/S. A demo is currently available via Steam Next Fest. Visit the Messhof website for more details.