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2018 Season 2 Release Notes [2018.03.05.01]
REMINDER:
This update is not deployed yet!
This is a preview of what's to come!
The 2018 Season 2 Release will be deployed on Tuesday, March 6th!
This release features a host of new content, updates, features, and fixes for the iRacing experience. We hope you have fun out on the track of your choice!
Some highlights include:
• Additional functionality and performance enhancements for the iRacing BETA Interface
• Custom Car Classes
• Extensive Rallycross Race Control updates
• Dirt Oval cushion modeling improvements
• Complete hand-over-hand animations for all vehicles
• Brand new crowd system
• Audi R18
• Dallara IR18
• Porsche 919 Hybrid
• The Dirt Track at Charlotte
• Limaland Motorsports Park
• Pocono Raceway track upgrade
• Sonoma Raceway (Rallycross)
Full 2018 Season 2 Release details are below.
CHANGE LOG:
iRacing BETA Interface
- Some extensive background system updates have been completed for the iRacing BETA Interface to greatly enhance the speed, responsiveness, and stability of the application.
- Fixed Setups are now available when creating Hosted Sessions!
- - When making the vehicle selection, you can activate the "Fixed Setup" switch near the top-right corner of the vehicle.
- - - This allows you to select or upload the Setups to be used for the Hosted Session.
- Spectator Sessions are now available for Official Races!
- - Activate the "Show Running Sessions" switch near the top-right in the "Official Races" section of the interface. Then, click on one of the running races, and click the "Watch", "Spot", or "Crew", buttons to start that activity for that session.
- - Individual spotter settings and spotter passwords remain in development, and will be coming soon.
- An additional "Download" button has been added at the top of the Updater menu screen, so you can start downloads even faster!
- Additional indicators for when the iRacing BETA Interface is loading and/or processing information have been added.
- The Time Attack Launch screen now features an "Overall" view.
- The Time Attack Results screen now always shows your current position at the top, if you have one.
- - Click directly on it to jump to your row in the Results table!
- The Time Attack Results screen now features "Go to Beginning" and "Go to End" paging buttons.
- Improved support for scaling the iRacing BETA Interface.
- Improved support for the use of 4K (UHD) monitors.
- - If we detect you are using a 4K (UHD) display, you will get a prompt asking if you want to enable 4K Mode.
- - - If you ignore the prompt, or if you click "Don't show me this again," you can enable 4K Mode by opening the Settings Menu and clicking "Enable 4K Mode."
- The system for painting the Primary Sponsor has been improved.
- Fixed an issue where using the Test Drive function for a Race Series during Week 1 would not work correctly.
- Fixed the usage of plurals (-s, or -es).
- Fixed some text bugs.
Hosted Sessions
- Car Classes can now be selected when creating a hosted race.
- - Sessions are still limited to a total of 6 unique cars per session, and car classes can contain from 1 to 6 cars. The car class selections are grouped by the number of cars in the class.
- - - Car classes are represented as tabs in the interface, so only the cars for the selected car class are displayed.
- - This feature is currently only available on the Classic Membersite, not on the iRacing BETA Interface yet.
Custom Car Classes
- You are now able to create and edit your own Custom Car Classes for Hosted Sessions!
- - When selecting the "Use Car Classes" Option when creating a Hosted Session, a new link called "Create New Car Class..." is now displayed above the Car Class tabs. This link brings up a dialog where you can enter a name for the Custom Car Class and select a group of cars for that Custom Car Class. For "Rel. Speed" (Relative Speed), there is a suggested value displayed, which is the average of all the selected cars, but any number between 0 and 200 can be used.
- - - Rel. Speed values for Car Classes are hidden unless the "Grid Together" option is selected.
- - The Car Class dropdowns will now display iRacing's Car Classes as well as any Custom Car Classes you have created. Custom Car Classes will include an asterisk (*) in the name. You can edit your Custom Car Classes by using the "Edit..." link, which is displayed when one of your Custom Car Classes is selected. This will bring up the same dialog used when creating a Custom Car Class.
- - By using Custom Car Classes, anything about a Car Class can be changed, although it is not recommended to stray too far from the original purpose of the Car Class.
- - Race Results from past races using a Custom Car Class will use the current name of the Custom Car Class that was used, not the name at the time of the event.
- - This feature is currently only available on the Classic Membersite, not on the iRacing BETA Interface yet.
Race Sessions
- An indicator denoting that a final Race event is Official (Ranked) or Unofficial (Unranked) has been restored to the Session screen and its Info page.
Dynamic Track
- Some updates have been made to the debris throwing system.
- - The physics for debris now utilize a new collision system. This should eliminate the ability for thrown particles to slip through walls, making their build-up more accurate.
Dirt
- Dirt heights across all areas of the track now allow for a greater possible range of dirt amounts.
- - This will allow for both a greater build-up of dirt on the track, and allow for deeper digging-down of the dirt surface.
- Dirt cushion modeling has been greatly improved.
- - This is a pretty big change to how dirt ovals behave as the tracks are worn in. With this update, the cornering force from the cushion and increased banking that naturally develops should be noticeably greater, and the outside should be faster as a result.
- The mean starting usage state for Dirt Oval Heat Races has been increased, and the variance of this value has also been increased slightly.
Rallycross
- The starting area for Rallycross tracks is now well defined for Race Control.
- - The F3 Black Box now correctly sorts the cars on the starting grid.
- The F3 Black Box is now aware of the starting area and the Joker Lap area when computing the time delta, and displaying information.
- - Cars on the race path are always displayed as normal.
- - Cars on the starting area are always dimmed, like cars in pit lane.
- - Cars on the optional path(s) always have a cyan background color across their row.
- The gained time rule can now deal with the Joker Lap, and should correctly maintain and track your yield status regardless of what path combination you take.
- Race Lines have been adjusted on some Rallycross configurations to improve accuracy.
- Excessive post-race penalty time is now converted to post-race lap penalties.
Lone Qualifying
- Fixed an issue where ghost effects and skids were showing up from other cars during these sessions.
Driver Swap
- iRating exchanges are now possible in scheduled driver-swap races. The Info tab on the Session screen will indicate whether or not iRating will be impacted by this particular team racing event. iRating exchanges in driver swap races are being enabled as of the deployment of 2018 Season 2 during the 13th week.
Hybrid Engines
- Hybrid system can no longer be deployed while pit speed limiter is active.
Controls
- The Sim should now make better estimates for controller calibration when initially starting up the Simulation.
- Joystick calibration routine has been adjusted to reduce the likelihood of a noisy joystick axis getting detected.
- Improved the ability to map a multiple button press trigger to a single control response.
- - For Example: Button A = Action 1 -and- Button A + Button B = Action 2
- Support for mapping actions to buttons that are permanently held down (for example a position switch that simulates pressing and holding a button), has been added.
- - When mapping button controls, iRacing would normally watch for the "button release" event before mapping that input to the action. But in this case a user can hit "Enter" when mapping the control to accept the held-button (or switch position) in its current location.
Feedback
- Markers have been added to the driving control interface elements to indicate if you are dragging your brake or clutch. Markers will light up if there is any input at all on a control.
Spotter
- A new switch has been added to the [SPCC] section of the "app.ini" file, called "carLowHiAtStart"
- - carLowHiAtStart=0 = Spotter "Car Low / High" calls are disabled for a short duration after the green. (Default functionality)
- - carLowHiAtStart=1 = Spotter "Car Low / High" calls are enabled as soon as you get the green.
Driver Animation
- Hand-over-hand steering animations have now been completed for all cars!
- - We have fully implemented driver hand animations for all iRacing vehicles.
Animated Pit Crew
- The pit crew members' running routes have been adjusted slightly to minimize clipping through larger vehicles.
- The pit crew members with a war wagon should now appear correctly on loaded replays.
- Fixed an issue where the animated pit stop was not appearing correctly with team swaps.
- Fixed an issue where the level-of-detail distances for some pit crew members was causing them to lose their heads.
- Fixed an issue where the pit stop could break when driving in backwards.
Opponent Cars
- All opponent-controlled vehicles will now have their actual gear and RPMs displayed in their cockpits.
Crowds
- A new system has been created and implemented for crowds at all tracks!
- - The folks in the stands should now appear more realistic than before.
- - This system will function as follows depending on your Crowd Detail setting:
- - - OFF = No crowds
- - - LOW = The crowds display with front-faces only
- - - MEDIUM = The crowds are in full attendance
- - - HIGH = Additional 3D characters are added around the track
Rendering
- Fixed an issue where some tires were showing up as white-wall or chrome-wall.
Replay
- Performance improvements have been made to the mechanism used to prepare the replay world for playback.
- - This change will be most noticeable when skipping around in a replay, getting out of the car in the Sim, and playing through a session change within a replay. The effect on the Skew (S) bar during these operations should now be greatly diminished.
Video Capture
- The video capture API has been updated.
- The file format, ".MP4" is now the default file format for the video capture system.
Telemetry
- The old telemetry session string will now clear when launching a new session via the iRacing Beta Interface.
Peripherals
- Support has been added for LED rev lights on the new Thrustmaster TS-PC RACER Ferrari Challenge wheel.
- The Fanatec Light API version has been updated to 3.2.
CARS:
Audi R18
- NEW CAR!
- - The Audi R18 has been added to the iRacing virtual garage!
- - This is a Le Mans Prototype (LMP1-H) race car, and is now available for purchase in the iRacing Store.
Audi R8 LMS GT3
- The range of toe settings has been expanded so target toe values may be achieved over a larger range of camber settings.
- Driver seating position has been moved further back in the car.
- - This change also alters the driver viewpoint.
BMW Z4 GT3
- Baseline setup has been adjusted so it can pass Tech with any fuel level.
Chevrolet Monte Carlo SS
- Season setups have been updated.
Dallara DW12
- All users who had purchased this vehicle within the past six months will receive $11.95 in iRacing credits. This is to compensate for the release of the Dallara IR18 so soon after their investment. Thank you for your purchase!
- This vehicle has been added to the garage of all users!
- - The Dallara DW12 is now considered part of the iRacing default content.
- Max Travel of dampers will now always remain positive.
- Honda logos have been removed from this vehicle.
Dallara IR18
- NEW CAR!
- - The Dallara IR18 has been added to the iRacing virtual garage!
- - This is the new IndyCar, and is now available for purchase in the iRacing Store.
Dirt Late Model
- (ALL) - Updated front bumpstop rate curves with more accurate data.
- (ALL) - Updated shock lengths and positions using more accurate data.
- (ALL) - Adjusted weight and inertia properties. Setups can now be more easily shared across all versions of the dirt late model.
- (ALL) - Trimmed nose valence and door skirts in the solid model to more typical lengths and adjusted collision elements accordingly.
- (ALL) - Adjusted collision elements in the nose and tail to allow closer racing per member suggestions and feedback.
- (ALL) - The driver's view position has been adjusted slightly.
- (Limited) - Improved cockpit engine sounds.
- (ALL) - Season setups have been updated.
Dirt Midget
- Two new iRacing paint schemes have been added to this vehicle.
- Garage fuel ranges have been updated to include three settings.
- - Lowest setting is for Qualification
- - Middle setting is for Heats and Consolation races
- - Highest setting is for Feature races.
- Season setups have been updated.
Dirt Sprint Car
- (ALL) - Last season's suspension update has been reverted.
- (ALL) - Nose wing angle is now adjustable in the garage.
- (ALL) - Garage fuel ranges have been updated to include three settings.
- - Lowest setting is for Qualification
- - Middle setting is for Heats and Consolation races
- - Highest setting is for Feature races.
- (ALL) - Adjusted the collision model of opponent cars.
- (ALL) - Season setups have been updated.
Dirt Sprint Car Non-Winged
- (ALL) - Removed the ability to make in-car cockpit adjustments to shocks.
- - 2018 USAC Rule Book 307-I: "Suspension adjustments by the driver from the cockpit will not be permitted."
- (ALL) - Garage fuel ranges have been updated to include three settings.
- - Lowest setting is for Qualification
- - Middle setting is for Heats and Consolation races
- - Highest setting is for Feature races.
- (ALL) - Season setups have been updated.
Dirt Street Stock
- Rev limit has been increased from 6200 RPM to 6800 RPM.
- - Season setups have been updated accordingly.
Dirt U.M.P. Modified
- Season setups have been updated.
Ford GT - 2017
- Fixed an issue where duplicate hub models were appearing when viewing from inside the cockpit.
Ford Mustang FR500S
- This car has been converted to now use PBR shaders.
- Fixed an issue where the mirrors were not using the correct aspect ratio.
Indycar Dallara circa 2011
- Honda logos have been removed from this vehicle.
McLaren MP4-30
- Hybrid control and deployment have been re-tooled. The existing deployment strategies have been replaced by a single strategy that is track-position aware. Deployment is completely cut when the car speed exceeds a fixed percent of the expected maximum speed on the current straightaway (end-of-straight or EOS speeds).
- - There are two user modes: Automatic and Manual Trim.
- - - In Automatic mode, the system calculates and applies an offset to the % EOS speed cut parameter that attempts to balance harvested and deployed electrical energy. Per the description, this mode requires no intervention from the driver - you simply get in and drive.
- - - In Manual mode, the user specifies a Trim via the MFH knob (1 to 14), in 2% increments from -12% to +14%. Setting 7 applies a 0% trim. -ve offsets cut deployment at lower speeds, resulting in net energy savings while +ve offsets result in deployment cuts at higher speeds, draining the battery. Note that the base %EOS speed cut parameter and expected EOS speeds are generated using ref-line calculations that have been modified to handle hybrid power units (ref-line calcs are used for the driving line display and race control functions like applying track-cutting time penalties in real-time).
- MGU-K power is now shown on the digital display.
- A Qualifying mode has been added for MGU-K deployment.
- Dynamic brake biasing and handling of MGU-K harvesting has been updated.
- - The car is now much more stable at brake release, even with very aggressive re-gen setting.
- The cure-based degradation and wear-based degradation of the tires has been increased.
- - Please evaluate this change over the 7-10 days after release, and please provide us with feedback. If necessary, we will adjust this again before the start of the F1 WCS.
Mercedes-AMG GT3
- 2018 Season 2 BoP adjustments: -15 kg minimum weight, reduced drag sensitivity for rear wing adjustments at greater than 4 degrees (so higher angles generate less drag), slightly reduced overall aero drag.
Modified - SK
- Season setups have been updated.
NASCAR Camping World Chevrolet Silverado
- Contingency decals have been updated for the 2018 season.
NASCAR Camping World Toyota Tundra
- Contingency decals have been updated for the 2018 season.
NASCAR K&N Pro Chevrolet Impala
- Season setups have been updated.
NASCAR Monster Energy Cup Chevrolet SS
- Contingency decals have been updated for the 2018 season.
- Season setups have been updated.
NASCAR Monster Energy Cup Ford Fusion
- Contingency decals have been updated for the 2018 season.
- Season setups have been updated.
NASCAR Monster Energy Cup Toyota Camry
- Contingency decals have been updated for the 2018 season.
- Season setups have been updated.
NASCAR Whelen Tour Modified
- Season setups have been updated.
NASCAR XFINITY Chevrolet Camaro
- Contingency decals have been updated for the 2018 season.
- Season setups have been updated.
NASCAR XFINITY Ford Mustang
- Contingency decals have been updated for the 2018 season.
- Season setups have been updated.
NASCAR XFINITY Toyota Camry
- Contingency decals have been updated for the 2018 season.
- Season setups have been updated.
Porsche 911 GT3 Cup Car (991)
- Anti-roll bar stiffness has been increased.
- Drivetrain stiffness has been increased.
Porsche 919 Hybrid
- NEW CAR!
- - The Porsche 919 Hybrid has been added to the iRacing virtual garage!
- - This is a Le Mans Prototype (LMP1-H) race car, and is now available for purchase in the iRacing Store.
Sprint Car
- Season setups have been updated.
V8 Supercar Ford Falcon circa 2012
- Fixed an issue where the mirrors were not using the correct aspect ratio.
TRACKS:
Atlanta Motor Speedway
- (Oval) - Track surface grip level has been increased slightly.
Circuit des 24 Heures du Mans
- Adjusted the audio system for the jet flyover.
The Dirt Track at Charlotte
- NEW TRACK!
- - The Dirt Track at Charlotte has been added to the digital landscape of iRacing!
- - This dirt oval track is now available for purchase in the iRacing Store.
- - - This is a stand-alone track; this is not a new configuration for Charlotte Motor Speedway.
Limaland Motorsports Park
- NEW TRACK!
- - The Limaland Motorsports Park has been added to the digital landscape of iRacing!
- - This dirt oval track is now available for purchase in the iRacing Store.
Pocono Raceway
- UPGRADED TRACK!
- - Pocono Raceway has been significantly updated to a version circa 2016, and includes a re-pave of the track surface.
- - The original Pocono Raceway has been re-named "Pocono Raceway - 2011".
- - This asphalt oval track is now available for purchase in the iRacing Store.
- - This track upgrade includes the following:
- - - Re-scanned and re-photographed the track.
- - - Using that scan, modeled new track geometry from scratch.
- - - Created brand new track surface textures for every surface using our latest methods.
- - - Upgraded a variety of the most prominent track objects from the old track by re-modeling and re-texturing them to our current art standards.
- Ownership of this track will be automatically granted to users who already owned the previous version, Pocono Raceway - 2011.
Pocono Raceway - 2011
- This track is formerly known as "Pocono Raceway."
- - It has been renamed to "Pocono Raceway - 2011" to make room for the upgraded version of the track.
- Ownership of this track will be automatically granted to all iRacing users, and it is now considered part of the default iRacing content.
Richmond Raceway
- This track is formerly known as "Richmond International Raceway."
- - It has been re-branded "Richmond Raceway" to reflect the changes to this track in the real world.
Sonoma Raceway
- NEW TRACK CONFIGURATION!
- - A new Rallycross configuration has been added to this track!
- - A member who already owns or purchases this track gains access to this new configuration.
USA International Speedway
- (Dirt) - Fixed a surface type bug on the back stretch of the track.
encore une grosse release
Le BOP sera à présent modifié en cours de saison, et il est vrai que la Mercedes avait perdu un peu de terrain face aux autres... En espérant que ces changements aient des effets minimes car ce serait une plaie si on devait changer de voiture à chaque fois.
There have been a bunch of questions raised in this thread and I'd like to answer as many as I can. I picked questions that came up multiple times, and questions or comments that were particularly on point. So here we go, somewhat in order of most asked:
1) Given what I know now, that this NTM effort was going to consume 10+ years of my life, do I wish I had pursued an empirical approach instead?
No. Absolutely not. I actually did pursue an empirical approach for 20 years, while at Papyrus and during the early years of iRacing. That taught me something important: an empirical approach gets slower and slower the more tires you try to model and the more cars you try to model. There are just too many variables, and to adjust them requires a lot of testing and feedback between changes. Inevitably someone will bring up an issue where the empirical model deviates from real tires, and that involves adding some new bit to the model, with more parameters, which now need to be added to all the tires and cars... more testing, feedback, ad nauseum.
With the physically based model, there has been a lot of work required to get to where we are now, but the development is getting faster, not slower. That's because the more we know, the easier it gets. There have been several times that the model produced a behavior that was surprising, but upon looking more closely at real data we realized that behavior was correct. Very often the numbers and concepts that we already know allow us to think more clearly about what we don't know. It's absolutely the right approach--I am stoked about the V7 model. Lots of things are right about it. Will it have some issues? Probably. It'll take a while to transition over to it as well, but it's a big step in the right direction.
As an example apart from tires, think about Ptolemy's epicycles as a way to describe the movement of the planets, versus Kepler's elliptical orbits around the sun. Ptolemy's model was definitely empirical. No way to figure out how many circles upon circles any particular planet needed, or how large those circles should be, or anything. It's just a massive curve fit against a model that has no basis in a theory of why. Kepler came up with a much better, simpler curve fit, though he also didn't know why. Sadly, he died thinking his 25+ years of work had been a complete failure because he hadn't been able to explain the divine order of the heavens. Isaac Newton, though, was aware of Kepler's work (amazingly, if you've ever read Kepler's work, which is... way out there) and it was one of the things that helped lead to his theory of gravitation. Look how much more progress resulted from Kepler and Newton's theory than from Ptolemy's. A good predictive theory beats big data any day of the week.
The Magic Formula is like Ptolemy's epicycles. It fits data well (sort of) and can predict with fair accuracy what needs to be predicted in most common situations. Our physically-based model is like Newton's theory, in that it is able to explain what's going on and even predict things we didn't know. Well, in fact it's way more sophisticated and interesting and way cooler than Newton's model of gravitation, but we've been able to stand on the shoulders of a lot more giants than Newton could, so he still wins the smartest guy award by, like, a long way. For example, Newton did all his important work before Euler was even born!! Plus we use Newton's theory of gravitation in the sim, and it works really well, so we have to give him that. Also, because calculus.
2) How do you go about validating all this work?
This is a great question, and unfortunately it has a much more complicated and unsatisfying answer than all of us would like. Ideal answer is: "For every element of this model we've devised experiments which have verified our theory, and we have published many papers in peer-reviewed journals, and our results have been independently corroborated in other laboratories around the world." Sorry, not that way. It's more like a mundane, everyday part of the process.
Fortunately, a great many scientists around the world have published books and papers in peer-reviewed journals which provide results that we can use to build our model. The most important thing to remember is that once we see a paper with some data, and we use that data to come up with a bit of theory, we can NOT use that same data to validate the theory. We have to find new data, which we haven't seen before. We often get data from auto manufacturers, or race teams, or even (rarely) tire companies, in addition to finding more books and more papers. Sometimes, we use data to theorize, sometimes we use it to validate. But not both. Data is often very dependent on the exact experiment conducted. Good papers will explain in great detail the conditions of the experiment reported and the materials used. Using that detail, I can reproduce that experiment virtually, sometimes with code, sometimes in a spreadsheet, and see what my model outputs. I have read a lot of papers reporting on dynamic experiments on rubber. Most of them provide the rubber recipe; if not, the data is of more limited value.
In creating any complicated simulation, there will always be a lot of unknown numbers. But the more we learn, the more those numbers become constrained to have a range of reasonable values. It's a bit like putting together a jigsaw puzzle. At first, it seems impossible, but once you begin to fit a few bits together, and the outline becomes clearer, the easier it gets. The process is always one of double, triple, quadruple checking against new data.
As a general principle, I'm always trying to eliminate any "magic" (i.e. inexplicable) numbers. Every number we use should have a basis in reality, either it was measured (and we know under what conditions), or it is derivable from a largely accepted physical theory. Some numbers are quite easy to derive, like the moment of inertia of the right front wheel about its spin axis. Some numbers much less so, like how hot will the right front carcass be after 20 laps at Charlotte? But many numbers are related to each other--the right front carcass temperature is related to the pressure build after 20 laps, and so if we know one of those numbers (we might learn pressure build from a race team), we can deduce at least a small reasonable range for the other. For a long time, the rolling drag for a tire was computed with an empirical model, because we had no way to really calculate what it was from first principles. And in order to make all the cars and tires end up with reasonable temperature and pressure builds we'd have to turn a magic knob, the Rolling Heat Multiplier, in order to get numbers that were in the right ballpark.
Now, we are able to compute rolling drag from the carcass model, and the material parameters in the carcass, which are also measurable. We'll retain the Rolling Heat Multiplier for now in case we miss the mark from time to time, but it had better turn out to be 1.0 (i.e. no change required to the model rolling drag) for almost every tire. If not, then that will be good information for us. Maybe it will be just about 1.2 for all the tires, in which case there is something that isn't being accounted for in the model, or maybe it will be some very different number for every tire, in which case I will start trying to figure out what I'm doing wrong. There aren't very many magic numbers like this left in the tire model. No magic numbers and all right answers = good model. In that sense, validation is a continuous part of the work.
Some validation certainly comes from "feel," and the feedback from real racers who should know how it feels. We do a lot of that sort of testing, too. But feel can be illusory, so we have to be careful. There is always lag in force feedback wheels, and a lack of seat-of-the-pants forces, which make controlling a slide more difficult than in real life. I always find that I'm over-driving the car in-sim and being too aggressive with the car (which I believe is fairly common among all of us). In the past, every time I'd do a race weekend, I'd be much faster back in the sim afterwards. Why? Because the real car would force me to be smoother and not over-drive it as much. Using that same approach in the sim is better. If it "feels right" in the sim, sometimes that means it's too forgiving of your (probable) over-driving. Once you get used to a more realistic, less forgiving feel, it's just as easy to control. You just have to be smoother and keep your eyes up so you can respond faster to over-rotation, or any other bad situation.
3) When will flat spots be modeled?
95% of the behavior of a lockup is modeled already. Nobody is being denied a championship because somebody else is locking up in every corner and paying no price for it. Modeling the remaining 5% is on the to-do list, but currently it comes after rain, which is another feature everybody wants--until they get it.
4) How much rubber curing is happening on track?
Not much at all, unless your carcass temps are greater than 265 Fahrenheit (130 C). This pretty much limits it to high speed oval racing, and even there it's just one effect out of several that reduce grip.
5) Tell us more about tire failure from excessive heat.
I don't want to over-hype this, it'll be some kind of rapid deflation event (i.e. inflation pressure goes to zero, just like current tire failures) based on exceeding some temperature for too long a time. The main thing is to provide a reasonable downside to running very low tire pressures. But even before failure, running pressures that are too low will in many cases not be fastest. Also, for now the behavior approaching, at, and beyond the critical speed can be a little weird due to some simplifications in the model. That is something I'm aware of and will try to address.
6) How reliable are lab results when reverse engineering rubber compounds?
These more provide a range of values, and constrain what's possible. We get a pretty good idea of how much of the compound is carbon black, less accurate is the determination of polymer vs. oil content. The lab tests give some raw data sweeps that are very useful, as well. Another double check is testing Shore A hardness of the tire's tread. But that depends on temperature, how long a reading (one second, three seconds, ten seconds?), and on the thickness of the tread, so care must be taken. Telemetry data is useful for grip determination (especially since our track geometry is close to exact), but aero forces need to be known precisely.
7) Why not update all the cars at once with the new tires?
Going to the V7 model is like having a new tire manufacturer come into a race series. Cars are often designed around the tires. Changing tire constructions and/or rubber compounds can change a car's handling quite a lot, even in the real world. So a lot of testing and setup work needs to be done. It's better to get feedback from a more limited number of cars at first. If there is something in the model that needs to be changed, we can do that without messing up setups for all the cars. Also, more work is necessary in the V7 code to properly do dirt. I think in the long run it will be better, but we'll probably stick with V6 on dirt for a while. Dirt masks the over-the-limit breakaway that is one of the biggest issues on pavement.
8) ...let's should be lets.
Oh jeez, I have to admit to being an apostrophe Nazi myself, so it's quite embarrassing to have let this slip through. Fixed! Thanks, Todd! Won't happen again...
9) How does this compare to the tire manufacturers' models, and would they be interested in what you're doing?
I don't really know the answer to this, but I can speculate. A large tire manufacturer has very different goals than a sim-racing developer. One, they don't need a model that runs in real-time. So they can use finite element analysis (FEM) extensively. For us, that's a little like ray-traced graphics from the movie industry. We may be able to get there some day, but probably there will always be a faster way to draw things. Tire manufacturers probably care the most about being able to sell more tires to a public that has little interest in driving at the limit. We are interested in selling more memberships to the limit-driving cognoscenti. The public buys tires based on the three things that are mandated to be measured by the government: grip rating (essentially how good the tire is at stopping while locked up at 40 mph on a wet road), mileage (miles per gallon of fuel burned, that is, essentially rolling drag on the highway), and wear rating (how many miles it will go before I have to buy a new one). Also, the public don't want their tires to pop when running over a beer can. On this, we can agree--racers don't want that, either. The public want tires that are not too noisy or harsh on the highway.
So much of the FEM work that tire companies do (but not all, I'm sure) has to do with: where and how does heat build up in the tire? What are the stresses at key points and how long can the tire materials last with that stress and heat? How can we better remove water from the tread area? How do we make the tread blocks quieter? If Joe Public doesn't pay any attention to his inflation pressures and is driving on the highway with 5 psi in a rear tire, how do we protect him from himself? And us from liability? How do we simultaneously increase wet grip, decrease rolling drag, and make the tire last longer? Can we do all this with cheaper materials? And of course, can we make a really cool video to run during the Super Bowl? (preferably with a little baby being saved by our FEM model graphics)
We care about the first (how and where of heat build up), but much less about the others. My guess is the tire companies are already able to get better numbers for their purposes than we are. But we are better at getting numbers for our purposes than they are.
10) Have you seen Nicki Thiim's video?
Yes. And I have to say, Nicki's videos are as much fun to watch as it is to listen to Jens Voigt announcing a bike race. In other words, awesome! And to be honest, he is right about the V5 slip and grip over the limit model. Although, I think it is not as bad as he makes it sound. Ok, it is if it's hot out. But he also says that he loves the "curb-surfing" (a great term) and that has much to do with the V6 carcass stiffnesses, which I think are very good. And he liked everything else about iRacing, including the graphics and track geometry realism. I think he's right about that, too.
11) What is the sampling rate of your physics model?
360 Hz, is the short answer. But we calculate forces twice per update step, so we do player tire force calculations at least 4x2x360 = 2880 times per second. More if some of the tires are contacting multiple surfaces (i.e. curbs). We use IEEE floats.
C'est sur sa to-do list mais bien que 95% du travail est fait, ça passera après la pluie
Pour la réponse 3, pas sûr qu'il ait tort en disant/rajoutant: "until they get it"
N'empêche que le jour où on aura différent type de gomme et qu'après 12H de course au Mans, il commence à pleuvoir au Mans à des endroits précis du circuit... et tout ça dans le noir... Je kifferai grave
... mais la taquinerie, la petite remarque (censée) en plus, ça m'a fait sourire
J'avais pas le son au boulot mais ce que j'ai retenu c'est qu'elle a la conduite à gauche donc c'est parfait ^^
et c'est pas rien comme détails
Bah bizarrement grace a testrive j'ai roulé avec la HPD ces derniers jours, et je me suis pas rendu compte de suite qu'elle était en conduite à droite... Je comprenais pas pourquoi je prenais des offtracks dans les virages à gauche ahah
Téléchargement en cours 4.75G.
+ les téléchargements optionnels! ... 3h30 de téléchargement! Ouch
Idem GGRRR
Alors ces LMP1 ça envoie du couscous ?
13 minutes de download, le temps de me faire à manger avant de faire craquer la carte de crédit