A video published recently by SideFX, the developer behind 3D animation software Houdini, has revealed some of the inner workings of Polyphony Digital and how the team uses procedural generation.
The four-minute clip consists of a to-camera interview with Polyphony Digital’s environment design team chief technical artist Akira Saito, who talks about the use of Houdini in developing Gran Turismo 7.
As an environment artist Saito is of course primarily interested in how procedural generation helps artists with the creation of the game’s tracks. For GT7 that includes not only landscapes but roads and buildings too.
One specific item Saito brings up is road junctions. Creating smooth and realistic intersections is something that’s difficult and time-consuming for the artists, but it’s possible to automate this process with Houdini.
Another area Saito notes is in polygon reduction in landscapes. This technique allows the environment team to simplify complex landscapes — such as distant mountains — to reduce the rendering workload of the console, while keeping them true to the original captures.
Importantly Houdini does this in a non-destructive manner. This preserves the information throughout the production pipeline, allowing for it to be retrieved and altered by the various artists.
Saito also comments on the recent implementation of Universal Scene Description (USD) for Gran Turismo 7’s development. Originally developed by Pixar, and first used in the animated feature Brave, USD is a technology for the collaborative creation of three-dimensional virtual spaces — sometimes used in manufacturing to create “digital twins” of real-world objects.
PD currently only uses USD with Solaris, a feature in Houdini for building scenes for look development (the overall aesthetics of a project) and lighting, but Saito notes that further implementations of USD are being investigated.
Elsewhere on the lighting front, Saito comments on the use of “metadata” — data not visible in the game itself — in real-time lighting and dynamic camera movements on the cars.
One final area in which PD uses procedural generation is in the vehicles themselves. Although Saito notes he’s not part of the car team, he does comment that they use Houdini in the creation of custom vehicle parts, including wheels.
Although it’s only a short video, it does nonetheless give a lot of insight into the graphical development of Gran Turismo, and a look at how the team may leverage these technologies to reduce artists’ workloads for future entries in the series.
