Creating game assets is a famously expensive business. With a team of hundreds it’s possible to produce your own take on Los Angeles, the Caribbean or even a postapocalyptic Washington DC, but smaller studios have neither the time nor the manpower to build game worlds on that scale using traditional modelling. One solution is procedural generation, which Hello Games is using to create the vast universe of No Man’s Sky. Another is a science dating back to the mid-19th century: photogrammetry.
Polish studio The Astronauts has employed photogrammetry in creating The Vanishing Of Ethan Carter’s lush world, and couldn’t be happier with the results. In general terms, photogrammetry is the accurate measurement of the environment and objects within it from photographs and other non-contact sensors, such as ultraviolet or thermal imaging. For The Astronauts, it’s an affordable alternative to expensive laser scanning (the technique used to capture actors’ faces in Alien: Isolation) and an efficient route to photorealistic texturing.
“The quality still gets us,” says art director Andrzej ‘Andrew’ Poznanski. “It’s sort of mind-blowing. I’ve seen my fair share of really high quality assets, I’ve worked with amazing graphics artists, but when I look at [assets created by photogrammetry], it still gets me. No art team, at least in a reasonable time frame, can capture reality and its nuances like photogrammetry.
“There are always tiny details that you lose [when creating assets] – those things that you don’t perceive consciously that make or break the reality. That’s especially true for how erosion works in reality: how moss moves up the walls and works its way into any crack in the
The Astronauts on why photogrammetry could revolutionise game making for small teams
pavement, how erosion shoots up the corners of stone blocks, and how rain hits a building from certain angles but not from others. These are all things you think you know, you think you notice them, but when you sit at a computer and create a game asset, you’ll most probably miss those things. Photogrammetry adds those things automatically.”
All you need to make use of this powerful technique is a camera and photogrammetry software (The Astronauts uses Agisoft PhotoScan, which Poznanski describes as “the best one out there”). Recreating an object takes around 40 to 50 photos to cover every angle once the shots are fed into the software and composited. Any camera will do, even an entry-level point-and-shoot, though the quality of your assets will obviously be dictated by the quality of your kit.
“Of course, it’s not quite that simple,” says game designer and The Astronauts co-founder Adrian Chmielarz. “There’s a lot of work before and after, but the gist of it is you photograph it, get it to the software and there you go: you have an extremely photorealistic in-game asset.”
That extreme photorealism pays little heed to memory limits, however. “Realtime graphics love repeating things,” Poznanski says. “Repeating assets, tiling textures along entire walls, with carefully placed geometry at angles wherever you need them and only as many as you need. Photogrammetry doesn’t care about that. It spits out millions of triangles where you only need a few hundred. It will give you one unique huge 4K or 8K texture where you would otherwise use a tileable, versatile texture that’s probably 64 times smaller, maybe with a few additional details.” The process doesn’t quite bypass the artist, then. There’s a lot of work to be done post-capture to clean up and optimise textures and objects, and even then they remain large. But thanks to the increasing amounts of graphics memory on PC cards and in Sony and Microsoft’s new boxes, these file sizes needn’t be a problem. Traditional occlusion methods still work, and play a bigger role in keeping things running at a decent pace.
Poznanski explains: “We’ve come up with a new method of texture compression in-house, which allows those huge textures to be two-and-ahalf times smaller than they would regularly be in memory.
“[Photogrammetry] requires a lot of tricks, but that’s the beauty of it: it still requires talent and experience. It’s not like everyone these days will be able to spit out huge open-world environments. But if you have the skill and you experiment with it a lot, it allows for great things.”
Chmielarz agrees: “Once you’ve figured it out – and it’s constantly being improved – it’s going to be a way of acquiring really high-quality in-game assets for a lot of studios, not just indies. But it’s especially important for indies; we have three-and-a-half artists producing an open-world environment that’s something like four kilometres square. If we weren’t working with photogrammetry, we would still have a pretty large game, but not to the extent we are shooting for now.”
“It’s going to be a way of acquiring really high-quality in-game assets for a lot of studios, not just indies”
From top: Adrian Chmielarz, game designer, and art director Andrzej ‘Andrew’ Poznanski