rFactor 2 – October Roadmap Update

October has just ended and obviously that can only mean one thing – roadmap update time! Reiza Studios published its dev update for October just yesterday and Studio 397 followed only a couple of hours later.

More (mod) content

Studio 397 just released its GT3 Power Pack for rFactor 2. But content for this year does not stop there. The developer is pushing to release a brand-new, still unannounced track before this year’s Christmas. Any guesses?

Moreover, the GT3 pack introduced rFactor 2’s new content store. Said Steam store has now been opened to third parties as well. So, in a couple of weeks’/ months’ time first third-party mods will probably start to appear as paid-content in the new rFactor 2 content store.

Progress on Zandvoort is being made as well but not as much as expected. Hence, the final version of the track will not arrive until 2018.

However, a lot more progress has been made on the model of Corvette C7.R GTE. Physics and sounds are now the current objectives for the car and even other GTE models are being considered and evaluated.

Some of the Tatuus models are already in development as well, although they are still their early stages.

Studio 397 also applauds the success the community has been having with Crew Chief and is now reconsidering its spotter situation in rFactor 2.

DirectX 11

Yes, DirectX 11 has probably been discussed more than enough by now, but Studio 397 really wants to get it right. Additional feedback was provided at this year’s SimRacing Expo and Studio 397 wants to take the time to implement the feedback together with content updates and an improved – not new – HUD.

A new HUD will appear at some stage next year and the stable DirectX 11 version is scheduled for launch within the rest 2017 together with the next major update. That update will then also feature the already teased rain effects.

Tyre physics

Lots of work is also going on in the tyre physics department too. Here is what Studio 397’s Michael Borda had to say on the struggles of implementing tyre physics and how Studio 397 overcame them:

Since the inception of rFactor 2, we’ve calculated centrifugal forces in a ‘quasi-static model’, thinking this simplification was correct or close enough to reality to not require deeper adjustment. It was considered fact, when in reality, accelerations should be calculated localized as the distribution in the contact patch can vary significantly to the original behavior. Some correlation issues crept up over time, and as we’ve collected more data, it became apparent that it wasn’t on the data side. You may think that this might be sloppy, however, the reality is the way data is measured, interpreted (smoothed / adjusted / fitted), scaled, or worst of all, even copied between tyres, makes trusting data a very difficult thing to do. In this case we had strong suspicions that the data was measured under a single condition, simply offset and then applied to different data points. This doubt left plenty of room for us to believe that our model was probably correct, when considering the obvious short-cuts the manufacturer had taken in measuring the data. So everything was rosy, we thought, and then we finally obtained the same type of data from another tyre manufacturer. This time, they went to the extra step of measuring at multiple loads. Once we had this corroborating information, it became obvious there was a glaring issue with our tyre model. Of course, this was an original part of the tyre model that hadn’t been touched for years, taken for granted. This was also a essentially a non-issue before the introduction of the contact patch model. After a little thinking and investigating, it became obvious that our ‘harmless’ simplification, wasn’t so harmless after-all.

To describe the effect in practical terms, after some early testing, it is quite obvious that the ‘speed sensitivity’ of tyres is decreased. A reduction of speed sensitivity, meaning that the tyres lose less grip as a direct consequence of rotational speed. The resulting contact patch is a little bigger (longer), especially when compared to the previous tyres under a combination of both high speed and load. As you apply slip angle, the longer contact patch increases the sliding speed towards the trailing edge of the contact patch, making tyres more prone to overheat at high speed. A larger patch also increases cooling (as contact conductance is the primary driver of heat dissipation in a tyre). In general, tyre temperatures will probably be slightly higher, so you may need to increase conduction slightly to achieve realistic temperatures. In terms of overall feeling, this is the biggest change in rF2 since the introduction of the contact patch model. This also marks the first major change to the QSA model itself.

So now, with the latest newly-released build, we now calculate localized accelerations, and our QSA model, becomes a little bit less “quasi-static” than before.

About the Author

Paul Heidekruger

Sim racing, tech, drums, guitars, music, games, everything with wheels, also 1/4 Kiwi.