It is no secret that Straight4 Studios have big ambitions for Project Motor Racing. A new insight video explains the intricacies of their physics engine - and it will be going very deep.
Realism is key in sim racing, of course, but trying to depict race cars perfectly accurately in a virtual environment is no easy feat. For Project Motor Racing, developer Straight4 Studios aims to go at least one step further, however: Their physics engine looks seet to be extremely in-depth.
In the latest video insight into the project (a series called Roots: Drivers Wanted), Straight4's Principal Vehicle Programmer Ben Ponsford explains some of the challenges and goals in Project Motor Racing's physics simulation, noting that real race cars can often feel slightly different to different drivers in the same or very similar conditions.
This is due to the complexity of a race car. In a very basic way of looking at it, there are a few main factors that influence how a car behaves - its tires, aerodynamics, weight and power, first and foremost. Of course, there is much more to it - and Straight4 aims to simulate more of these intricacies. One of them even came naturally via their SETA-based tire model.
Straight4 Studios secured a publishing deal with GIANTS Software of Farming Simulator fame for Project Motor Racing.
He continued: "They talk about this bite the cars have, an immediacy to the turn-in that happens before they settle into the corner. We were able to see that it is actually a real thing, and it pulls out of the tyre model naturally, which we were pleased to see. That was the coolest thing that we've got out of the new physics."
There is more to it, too. The Project Motor Racing physics engine will run at a refresh rate of 720Hz, "but that is only the tip of the iceberg." While the vehicle movement, tire info and deformation, and the suspension operate at this frequency, but Ponsford also highlighted the various driveline components and how they interact with each other - which will be simulated at 7.200Hz.
Image: Straight4 Studios
In May 2023, Reiza and Straight4 announced that they would be cooperating, and Straight4 CEO Ian Bell specifically stated that he was "enormously impressed with what Renato and his studio were able to create in terms of feel and handling with Automobilista 2." It would not be far fetched to think that this tire model progress also benefitted from this cooperation.
The internal combustion engine model is based on physics attributes as well, such as the number of cylinders, an engine's bore and stroke and more, with them having an (ideally) accurate effect on torque curves and other aspects of the engine's behavior.
While this may sound complicated, it should - at least in theory - result in a much more accurate simulation of the driving without making it more difficult, but rather more natural. We are certainly keen to find out how this translates to the feel in our rigs once a playable version of Project Motor Racing becomes available.
"That allows us to see how the real engineers, over the course of its career, have made changes from track to track and over time as they've learned things", explained Ponsford. "We can go back and look at that data and try to understand, why have they done it? Does it make sense to us with the model that we've got, does it always feel like an improvement? Because it should do.
"We can also look at the track-to-track setup differences they made, and if we should be able to apply those same differences that they've made and it should work in the sim as well. That would also just verify that the whole detail of the model that we've got is correct."
What are your impressions of the physics engine insights for Project Motor Racing? What would you like to see in the sim? Let us know in the comments below and join the discussion in our Project Motor Racing forum!
Realism is key in sim racing, of course, but trying to depict race cars perfectly accurately in a virtual environment is no easy feat. For Project Motor Racing, developer Straight4 Studios aims to go at least one step further, however: Their physics engine looks seet to be extremely in-depth.
In the latest video insight into the project (a series called Roots: Drivers Wanted), Straight4's Principal Vehicle Programmer Ben Ponsford explains some of the challenges and goals in Project Motor Racing's physics simulation, noting that real race cars can often feel slightly different to different drivers in the same or very similar conditions.
This is due to the complexity of a race car. In a very basic way of looking at it, there are a few main factors that influence how a car behaves - its tires, aerodynamics, weight and power, first and foremost. Of course, there is much more to it - and Straight4 aims to simulate more of these intricacies. One of them even came naturally via their SETA-based tire model.
Straight4 Studios secured a publishing deal with GIANTS Software of Farming Simulator fame for Project Motor Racing.
Big, Positive Tire Model Surprise
"The biggest surprise we had was during development of the tire model. We ran it in a test environment at various different frequencies, and if you run the frequency at tens of thousands of times per second, you start to see this emergent behavior", noted Ponsford. "You get an initial peak of grip come out of a tire laterally, which very quickly fades away and then goes back to the normal slip curve behavior that is much more known. We have not seen this sort of phenomenon mentioned in any sort of publications, but race drivers talk about it."He continued: "They talk about this bite the cars have, an immediacy to the turn-in that happens before they settle into the corner. We were able to see that it is actually a real thing, and it pulls out of the tyre model naturally, which we were pleased to see. That was the coolest thing that we've got out of the new physics."
There is more to it, too. The Project Motor Racing physics engine will run at a refresh rate of 720Hz, "but that is only the tip of the iceberg." While the vehicle movement, tire info and deformation, and the suspension operate at this frequency, but Ponsford also highlighted the various driveline components and how they interact with each other - which will be simulated at 7.200Hz.
Image: Straight4 Studios
Straight4-Reiza Cooperation Possibly Helped
The SETA tire model is also present in Automobilista 2 via the Madness Engine - to which some of Project Motor Racing's team are connected via their work on the Project CARS a few years ago. AMS2 developer Reiza Studios has made big progress with that tire model and is set to release a big overhaul in this area, among many others, with their upcoming v1.6 update.In May 2023, Reiza and Straight4 announced that they would be cooperating, and Straight4 CEO Ian Bell specifically stated that he was "enormously impressed with what Renato and his studio were able to create in terms of feel and handling with Automobilista 2." It would not be far fetched to think that this tire model progress also benefitted from this cooperation.
Physics-based Internal Combustion Engine Model
"And the new internal combustion engine model we've got is actually very much quicker than that", according to Ponsford."We actually simulate every two degrees of crank rotation. That means something like 36.000Hz for typical RPM range that the race car engines will be running at."The internal combustion engine model is based on physics attributes as well, such as the number of cylinders, an engine's bore and stroke and more, with them having an (ideally) accurate effect on torque curves and other aspects of the engine's behavior.
While this may sound complicated, it should - at least in theory - result in a much more accurate simulation of the driving without making it more difficult, but rather more natural. We are certainly keen to find out how this translates to the feel in our rigs once a playable version of Project Motor Racing becomes available.
Blending Driver Feedback With Data
And it is not like Straight4 are simply relying on the physics engine to do its job and call it a day, either. For one, the studio works with Handling Consultant Ben Collins to gather feedback, and on the other hand, they acquired all the setup data for their hero car featured in their videos - the Lister Storm GT that @Michel Wolk and I got to see up close at Silverstone earlier this year."That allows us to see how the real engineers, over the course of its career, have made changes from track to track and over time as they've learned things", explained Ponsford. "We can go back and look at that data and try to understand, why have they done it? Does it make sense to us with the model that we've got, does it always feel like an improvement? Because it should do.
"We can also look at the track-to-track setup differences they made, and if we should be able to apply those same differences that they've made and it should work in the sim as well. That would also just verify that the whole detail of the model that we've got is correct."
What are your impressions of the physics engine insights for Project Motor Racing? What would you like to see in the sim? Let us know in the comments below and join the discussion in our Project Motor Racing forum!
