If you remember the lead-up to the release of Forza Motorsport, you might also recall that developer Turn 10 Studios had promised the post-launch addition of ray-traced global illumination (RTGI). However, nine months after the October 2023 debut of the game, there’s been no further mention of the feature in an official capacity.

Thankfully, Forza Motorsport forum user Viper3dc discovered a way to enable RTGI on PC via a ‘mod’. All you need to do is grab the XML files from the Visual Target folder (within the Forza Motorsport\Content\media\pcfamily\renderscenarios folder) and copy them into the Ultra folder, thus overwriting the Ultra settings.

Digital Foundry’s Alexander Battaglia has now analyzed the mod and found out that it improves visuals in various ways beyond just ray traced global illumination. For example, the Visual Target preset improves draw distance, level of detail, and object density, including grass.

Interestingly, this preset also expands ray traced reflections to apply to rougher materials. The expansion greatly improves visuals when using cockpit view, for instance.

Of course, the biggest visual improvement comes from enabling RTGI, which enhances ambient shadowing across various track details and adds bounce lighting, allowing local lights to take on the color of the surfaces that are being reflected.

There are various caveats to modding Forza Motorsport, though. There may be visual bugs and crashes, and replays do not appear to be using the correct ray-traced reflections, which means gameplay will actually look better. Moreover, RTGI appears to occasionally introduce visible noise and even some flickering, and the rain appears to be incorrectly reflected on the roads at nighttime. Then there’s the added performance cost, of course. With an RTX 3080 at 1440p, the Visual Preset mod runs 27% slower than the Ultra preset when using the default camera view. The performance cost is even higher with the cockpit camera view, going up to 40% slower performance when the mod is enabled.

These downsides are to be expected, given that Turn 10 still hasn’t officially enabled these advanced graphics settings in the game. They can currently be considered as a preview of a potential future update.