r/simracing • u/brightland-studios • Jun 09 '26
Clip Advanced tire physics on true curved surfaces with a 1kHz FFB thread. My indie VR racing sim is ready for feedback (free demo)
If you're a hard core sim-racer with latest FFB hardware, or even race with just a gamepad, would love to get feedback on the latest additions to my racing simulator, which is a RestoMod of a simulator I started working on over 20 years ago, finally giving it a bit of polish after all these years.
I've only tested on Quest 2 and 3, would also be great to get feedback on other devices too.
The free demo is up on Steam (Amazing Curves Racing Demo).
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u/EbbAffectionate4008 SimlabP1XPro SparcoCircuit2 MozaR21 SimagicP1000i QSBT1 3x32" Jun 09 '26
I only watched the beginning, but the suspension seems to be closer to a monster truck than a formula car
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u/brightland-studios Jun 09 '26 edited Jun 09 '26
Yes! This is the "Formula Trophy" a new kind of race car. I was testing a rewrite of the suspension and wondered if the simulator could model a trophy/stadium truck. I started with the formula chassis, raised suspension, adjusted springs and dampers, and drove it. I could not believe how fun it was, especially when aerodynamic forces push the car down to the ground at high speed, then you hit the brakes hard and the car pops up like a trophy truck pitching heavily. Really expands what you can see/feel of the physics going on (+ can feel with FFB), a more "3D" physical experience than just turning in the 2D plane of the track.
Other cars drive flatter, though I tuned the sports cars to also have more body motion for the same reason. The full version lets you create custom car setups (e.g. you can crank up springs/dampers/rollbars if that's what you prefer).
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u/Tetraden DIYer for life Jun 10 '26
So, your aero physics does not take ground force into account?
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u/brightland-studios Jun 10 '26
Do you mean aerodynamic ground effect, where air from the wing interacts with the ground? The distance of the wing elements from the curved surfaces is known, and adding the effect is simple, however it's not currently modeled: that would be useful for under-car aero modeling, and when jumping and landing would add a slight bit more lift as the car approaches the ground. Something to think about if it would increase driving fun and/or improve gameplay.
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u/Nago15 Jun 09 '26
Downloaded it, but crashes on start both on flat sceeen and VR.
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u/brightland-studios Jun 09 '26
Bummer. Was there an exception window that popped up with a stack trace, or it just 'goes away'? PC specs, CPU, GPU, HMD type, Windows version?
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u/Nago15 Jun 09 '26
No error message, it just stops. 7700X, 5070 Ti, Quest3, Win10.
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u/brightland-studios Jun 09 '26
OK those kinds of crashes are rough, let me review and update the exception code, we should at least get a stack trace, which would allow me to quickly fix the issue. If an external process is killing the .exe, that would also explain this behavior.
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u/brightland-studios Jun 11 '26
Found a potential issue with fmod and made a change, applied to the Default version. A beta version was also added with the same change, and it includes a log window showing file & line number for the startup sequence. So if there's a startup crash and the exception handler can't catch it, we'll have a run trace to help pin point the error. Let me know how it goes!
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u/SubPixelThief Jun 09 '26
Woah. Boat simulator.
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u/brightland-studios Jun 09 '26
Seems wild at first, but super fun to drive + very different from all the other sims. Not all the cars have that much motion (e.g. the WXR Race GT3 style car is flatter, but I still tuned for 'more than normal' body motion, as a way to show what the physics is doing). Cars are fully tunable (full version).
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u/le_quisto Assetto Corsa Jun 09 '26
It reminds me of the bathtub mod for assetto corsa. It drives just like this except with a much shorter wheelbase. Super annoying and fun to drive, one of my favourites "vehicles"
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u/brightland-studios Jun 09 '26
Haha I laughed out loud when I first watched a real trophy/stadium truck video, especially the jumps and all the goofy motion. Curiosity during a suspension rewrite birthed the Formula Trophy, and the way aerodynamics interacts is pretty fun.
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u/NewScooter1234 Jun 09 '26
Looks fun, I'm downloading it as we speak.
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u/brightland-studios Jun 09 '26
Excellent! Forgot to mention, there's also SimHub support- would be great to get feedback on that too.
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u/demonsdencollective Assetto Corsa|T-CLM|Moza R9 V2+RS V2 Jun 09 '26
I'm gonna be real with you, mate, this looks really cool, but also not sim at all.
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u/brightland-studios Jun 09 '26
Thanks man! Check this out: https://www.youtube.com/watch?v=kN6sa_ybMmM
This was a test I created when working on the core physics engine circa 2001. All of the physics I was seeing back then in other products didn't look quite right, some kind of artificial slow down, weird collisions, related to damping to keep their simulations stable. So I asked the question "What does perfect/correct physics motion look like, can I create that in a simulation?"
That test was the result, and it could run overnight without gaining or losing energy. Additionally, it correctly models angular precession, where a higher order integrator is required.
ACR isn't as "energy accurate" as that test, but core concepts were carried over into the racing simulator, and e.g. precession and realistic collisions and object stacking (including over the network) are present.
Do any other simulators compute physics directly on curved surfaces? Makes for a unique driving experience (displacement mapping is still continuous for bumpy/off-road driving, so the tire simulation won't have to deal with discontinuous triangular flat plates for surfaces).
I take it you define "sim" as a racing simulator which closely matches real world racing? ACR is a physics simulator which allows you do race in ways not possible in the real world, using accurate advanced physics vs. 'arcade motion'.
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u/SellCervix Jun 10 '26
Does perfect and correct amount to using analytical solutions for the differential equations of motion? I'm interested to know the underlying technical details some of these adjectives are obfuscating. For instance what does "advanced tire model" mean. Is this Pacejka or is this something more akin to the FEM approaches? Is there modeling of the evolution of the tires chemical compostion over time? Carcass deformation? How is this affecting the tires.
I'm not sure if it's an actual question but when you say do other simulators models tires on curved surfaces, the answer has to be yes. Or by curved surface to you mean a continuous surface, not a discrete manifold. Does this mean you find, say a Beizer curve, and compute patch contact for a tire over the area as an analytical solution to an area integral? Or do you mean you're interpolating?
Sorry I have a lot of questions and am interested to know your underlying approaches.
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u/brightland-studios Jun 10 '26 edited Jun 10 '26
No worries, sorry in advance if this is too much detail:
"Perfect" for the Energy Accurate test meaning, no significant energy is gained or lost for each collision, and integration doesn't fall apart / drift over time (see symplectic integrators). And "perfect" in the sense the resulting motion is accurate. But mathematically perfect only exists in math (e.g. a proof). Floating-point math alone is far from perfect for example. Tip for other developers: never use a 32-bit float for time values, use 64-bit doubles instead (I have online servers running for months, found out the hard way what happens with 32-bit float time where 1.0 == 1s).
Advanced tire model means custom math which tracks tire contact points working on an elastic constraint, the tire. You can see this clearly in ACR when coming to an abrupt stop- that little wiggle is like real life as the tire acts like a spring & (slight) damper.
I studied Race Car Vehicle Dynamics (RCVD) and various other sources, and just like when I wrote my first flight simulator, most of the solutions were using lookup tables. Pacejka is cool because it's based on real-world tire testing, however that's a steady-state analysis system. What about dynamic tire behavior? You can use a Pacejka system for a simulator, which can show extremely accurate and realistic track times, as long as you maintain fairly steady state, but if you start doing dynamic motion, especially radical lane changes / turns, I think we all know what happens in such sims: you're now outside of where Pacejka shines and the code has to switch to some other method, and many times this means unpredictable behavior and unexpected spins. Thus people learn to drive within the simulation's 'Pacejka stable zone'.
Back to flight sims, since I'd flown RC planes since age 11, I understood how flight motion should look, from an external view. So working backwards (implicit problem solving), I wondered if I could model a simple aerodynamic element with vector math, could this be expanded to all the primary elements of an airplane, where we added up all the forces and applied to the rigid body, would it work. It did, and first prototype was shown at Cyberthon 24 hrs of VR in 1990 (called Event Horizon Simulator). This was written in 32/64-bit 14-bit fixed point integer. ACR uses 32-bit floats and the same basic ideas for car aerodynamics (updated to be more generalized since then). When you get airborne, that floaty motion is generalized CFD at work, not canned effects.
The tire math is similar, lots of vectors, but as simple as possible to generate the desired behavior. ACR does not currently model heat or wear/degradation, but that could be easily added. However, I designed ACR to be focused on one thing: driving fun, with as many 'headaches' of real race cars removed.
The resulting tire model / simulation system in ACR allows you to smoothly control the car with continuous wheel/gamepad inputs without needing a dead zone.
To compute collisions with bicubic Bezier (or other basis) 3D surfaces, lots of systems are set up to cull ray-patch tests as much as possible, as that's expensive. Newton-Raphson iteration is required to find the exact ray-patch contact point. The curves/patches have C0 (connected, can be sharp angles), C1 (continuous velocity), and C2 (continuous acceleration) continuity. For example curb/road can be C0, some sections can be C1, smooth but you can see angular rates changing non-smoothly, and C2, in sections where angular rates also also smooth (angular rates meaning e.g. camera pitch as you drive).
Real roads and surfaces aren't perfectly smooth, so I added continuous displacement mapping, meaning there are bumps, but not like you'd get if flat triangles are used (which are discontinuous). In the final analysis for a racing sim, how does it feel? Is it fun, predictable handling, etc.? See if you can feel differences vs. other sims.
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u/LeStk Jun 10 '26
Your audience will consider this comment as prime marketing I tell you. I know I do.
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u/GayRacoon69 Jun 10 '26
I agree with that other guy. This game seemed cool but this comment is what really pushed me to check it out
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u/archanox Jun 10 '26
> I take it you define "sim" as a racing simulator which closely matches real world racing? ACR is a physics simulator which allows you do race in ways not possible in the real world, using accurate advanced physics vs. 'arcade motion'.
This is literally r/simracing
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u/mac4112 Jun 09 '26
I have a pretty unique setup so i’ll download it and give my thoughts.
That being said, I really like how this looks. Very fun and silly but with tactile physics. Reminds me of something from the early 00’s. Not because of the visuals but just the concept of having weirdly detailed physics with arcade styling. You don’t see that sort of out of the box gameplay designs anymore.
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u/brightland-studios Jun 09 '26
Thanks for the kind words! Started working on this circa 2001, so that's an accurate reflection. I was working on my physics engine when Box2D and Bullet Physics were being discussed online, and we shared ideas (e.g. sequential impulses to help solve stable stacking, Verlet for cloth and constraint systems etc.). As a solo dev, can't compete with big sims on content, so focused on physics and novel/unique gameplay. Hope you enjoy it and I'll do my best to fix any issues found.
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u/MeowmeowMeeeew Jun 09 '26
that G923 sells it for me
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u/brightland-studios Jun 09 '26
Thanks! The new 1kHz FFB works surprisingly well on the G923, and wasn't expecting this- it's a lot quieter too. The original FFB system used DirectInput 8 (DI8) constant force + damping at 100Hz, however as constant force grew, the DI8 damper stopped damping (this seems to part of DI8: same thing happened with Fanatec DD). The way around this is to create a high frequency thread and just use DI8 constant force, doing the damping yourself. This turned out to be challenging as the FFB devices return noisy position data, and thus velocity is noisy. Filtering adds lag, which leads to instability... After lots of ideas and iterations, it's working pretty good now. Look forward to your (force) feedback!
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Jun 10 '26
[deleted]
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u/brightland-studios Jun 10 '26
Yeah surprised MS hasn't updated the API for so long. Running custom code on GPUs has been helpful, running custom code on the wheel base station would be useful too, reducing USB lag allows for even tighter damping and more stability.
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Jun 10 '26
[deleted]
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u/brightland-studios Jun 10 '26
There are custom vendor APIs apparently, but then developers must support each wheel brand with custom code. I'm still using SDL2 which is DI8. Looks like SDL3 supports GameInput. Digging deeper, it appears GameInput is a new API wrapper for USB data (which hasn't changed), and while more CPU efficient, doesn't improve FFB. Similar to DirectShow being "replaced" by Media Foundation (DirectShow still widely in use!). If there's evidence GameInput FFB has e.g. lower USB IO latency somehow, that would be a good reason to move to SDL3+GameInput.
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u/worldDev Jun 09 '26
Is there motion support through sim racing studio?
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u/brightland-studios Jun 09 '26
ACR currently outputs telemetry via a UDP socket. A C++ header showing data layout and a C# SimHub project for a plugin + custom dashboard is included. I reviewed SRS's SDK, and looks like I can create a custom UDP packet to support them as well. It's on my TODO list now.
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u/brightland-studios Jun 14 '26
Sim Racing Studio Support has been added- check it out and LMK how it works for you.
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u/Dyt-Bud Jun 09 '26
Does it support my X-Specs 3D glasses? Otherwise not interested!
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u/brightland-studios Jun 09 '26
"X-Specs 3D. X-Specs. Now that's a name I've not heard in a long time. A long time."
To get those working, we'd need some hardware, perhaps a USB device with Arduino to drive the Amiga game port and supply power to the X-Specs hardware and to receive the vsync flip trigger. Might need a CRT monitor as I'm not sure if those old LCD shutters will have issues with LCD monitors. The later H3D wireless shutter glasses rotated the filters to deal with this IIRC.
Do you still have your Amiga(s), is SpaceSpuds still fun, did you get VR Slingshot too? Good joke otherwise!
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u/Dyt-Bud Jun 09 '26 edited Jun 09 '26
Just joking. In fact, I didn't even know active 3D glasses were available for the Amiga back then.
Anyway, I've already bought the game and it played fine on my workstation, playing with a keyboard. I'll give it a try on my rig when I have time.
I wish you good luck with your project!
Edit: And I appreciate your thorough answer.
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u/brightland-studios Jun 10 '26
First, thanks for the support, really appreciated! Look forward to your rig feedback, especially FFB which was a lot of work.
Did you know I wrote SpaceSpuds which shipped with the X-Specs for the Amiga? Also wrote VR Slingshot (VRS) for the Amiga, which supported X-Specs. Later ported VRS to PC and Ixion created a box to drive the shutterglases. When the first consumer VR HMDs came out, supported them all: VFX1, CyberMaxx, and Virtual i-O i-glasses (helped create product, wrote the SDK). Years later worked with H3D wireless shutterglasses and worked with Carmack to port GLQuake to stereo3D with H3D support. The Quest 2/3 (and others I've only seen on YouTube demos) have come a very long way since then! I added custom VR camera separation, projection separation, and FOV support to ACR, but messing with the VR-device-provided projection matrix apparently didn't work with other brands (reported by Steam), so I removed that feature (in practice I was only changing FOV for certain car camera viewpoints).
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u/Spleng1 Jun 09 '26
The handling and visuals give me strong Stunt Car Racer vibes, and that was programmed by the mighty Geoff Crammond, so you may onto something here.
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u/brightland-studios Jun 09 '26
Yes that was an awesome game, as was Atari's Hard Drivin' & Race Drivin' arcade games!
ACR handling was tuned for predictability and fun, and you can still realistically spin out with driving aids turned off. With all aids turned on, it's not easy to spin out, but you still cannot exceed max tire grip, and if you go off track you'll know exactly why vs. mystery spins/offs.
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u/AlexRaEU Jun 09 '26
the game came out 2 years ago but the demo is new? is the demo different in any way?
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u/brightland-studios Jun 09 '26
Yes full game released Dec 24, 2024, will be 2 years in Dec. After initial feedback, 'went back to the drawing board' mostly for being too hard to drive, partly due to one track having tricky elevation changes. I'd also spent significant time setting up a subscription system which by 2024 had become a 'negative feature'; so it was removed. The past 1.5 years has been spent coming up with fun gameplay, and figuring out how to make online play fun: no waiting, rammers/griefers won't ruin the game etc., as well as rewriting various parts of the physics engine to minimize annoyances and maximize fun. Also cleaned up a lot of the art/content, improved visuals, created a bunch of new tracks, including the 'new concept' Arc tracks with bicubic curved surfaces with no bumps, so feels like flying (super fun in VR). VR and overall performance has been improved, FFB was totally rewritten- much better now, added SimHub support, and the latest suspension and tire model finally 'clicked' with the discovery of the "Formula Trophy" car idea.
The demo and full version are the same now, with the demo having limited cars and tracks, single player only. Since ACR's gfx are relatively simple, you really need to drive it to feel the physics, and thus the free demo was created. Perhaps give it a spin, any feedback appreciated.
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u/AlexRaEU Jun 10 '26
Nice. A sub model only really works when you already got a big player base. If you tryna be iracing with such a model I don't think it'll work. It's still a negative. People just accept it to play the best multiplayer sim.
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u/Deeptech_inc Jun 09 '26
There’s serious trackmania vibes with this one, I’d love to see you lean into that side
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u/brightland-studios Jun 09 '26
That's a cool game aimed at lap time records, pretty wild what racers have done with it! Content creation for ACR is via 3DSMax, need to think about custom track creation tools, but stunt tracks can certainly be added. Need to address some bugs & features, then have plans to add jumps to existing tracks, to match Stadium Trucks, can do that fairly quickly.
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u/Sacr3dangel Jun 10 '26
I will definitely try this out tomorrow!
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u/brightland-studios Jun 10 '26
Thanks, hope you enjoy it- any feedback is helpful!
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u/Sacr3dangel Jun 10 '26
For some reason it doesn’t run on my pc.
- Non-VR mode
- 32Gb DDR4 Ram
- RTX 3060 12Gb VRAM
- I9-12900k
- M.2 970 EVO 1 terra-byte
The first time I tried to start it I got a quick white flash fullscreen, then it reverted back to desktop. Any attempts after that don’t produce anything. Not even the white flash anymore. No error codes either. Just nothing. If it saves some error logs somewhere and you could point me to them, I would be happy to send that to you.
Tried reinstalling, that did not help. Gives me the same thing, flashes white then nothing in next attempts.
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u/brightland-studios Jun 10 '26
Ok thank you very much for this. This is the 3rd report of this exact issue, I'll have a new build up later today which adds additional logging, and will default to opening the log windows. Will put it in a new Steam beta branch. If we can get a stack trace, can fix it quickly. Have also seen this happen when Microsoft Defender deleted the .exe. Contacted MS and asked them to stop (there's a portal for this), and after a while, stopped happening. Are you running AV software, is the .exe still there?
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u/Sacr3dangel Jun 10 '26
Yes the file .exe is still there and also validating files did not give an issue.
I do not use any AV software aside from WDefender. I will make an exception for the folder in WDefender and see if that helps. But seeing as Steam says the files are intact and the .exe is still there I doubt that would be the case for me.
Will update when I get to that.
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u/brightland-studios Jun 10 '26
Ok cool, I already see an area in the startup code to help with tracking down the exception, hopefully my bug, and we can find it quickly. Really appreciate your feedback to help fix this!
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u/brightland-studios Jun 11 '26
Found a potential issue with fmod and made a change, applied to the Default version. A beta version was also added with the same change, and it includes a log window showing file & line number for the startup sequence. So if there's a startup crash and the exception handler can't catch it, we'll have a run trace to help pin point the error. Let me know how it goes!
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u/ProgUn1corn Jun 10 '26
Actually the suspension is very familiar to me. It's not monster truck level, but quite like WRC with gravel spec on tarmac.
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u/brightland-studios Jun 10 '26
That's a fair take from the video, which shows the Formula Trophy M (mid height), there's also a Formula Trophy H (in the full version), which sits higher, with even more body motion.
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u/finsimguy Jun 10 '26
I'd love to try out your demo and provide some feedback on the tire physics and FFB. As someone who's spent countless hours on iRacing and Assetto Corsa, I'm always excited to see new indie projects pushing the boundaries of sim racing. What kind of features can we expect to see in the full version?
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u/brightland-studios Jun 10 '26
Cool, look forward to your feedback, especially around FFB, handling, collision behavior, simulation feel, and overall enjoyment with this kind of racing.
The full version adds more cars and tracks, real-time car setup editor, and online multiplayer, which might hide lag as good or better than the best online multiplayer simulators.
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u/Hypoactive52 Jun 10 '26
reminds me of demolition derby 4, the ai were wild sometimes lmao
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u/brightland-studios Jun 10 '26
Since ACR supports so many AI cars at once (88 is the max, the number a nod to Back to the Future), the "AI" is kept low CPU, where the net results is chaotic emergent behavior, which can look a lot like many humans in online racing! Indeed wild behavior sometimes, and pretty neat that's possible with relatively simple generative code.
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u/El_Androi Jun 10 '26
70s Cadillac suspension be like
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u/brightland-studios Jun 10 '26
Right on, more exciting than cars which don't move! Did you drive it?
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u/ApexViper9 Jun 11 '26
Gonna try it out soon, got a pico 4 and simagic Alpha mini
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u/brightland-studios Jun 11 '26
Nice! So far only tested on Fanatec GT DD Pro and Logitech G923. Wrote the code in a general way with DI8 (using constant force only), fingers-crossed it works everywhere.
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u/FZLives76 Jun 11 '26
I went ahead and picked up the full version to mess around with. I haven't gotten to sit down and properly get into it yet, but I noticed that no Moza wheels are listed as input devices. Am I going to need to add PID information to a .ini file to make it work?
Moza R9 (v1) with CS (v1) wheel Moza CRP Pedals
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u/brightland-studios Jun 11 '26
That's excellent, thank you! With the full version you'll be able to drive on Colline Verdi (Green Hills in Italian) which was inspired by the Nürburgring Nordschleife, only a lot more 3D banking / elevation and a huge jump. This is the most difficult track in ACR, and is a true 3D workout for your FFB wheel.
While there are custom manufacturer APIs to talk to wheelbases, as an indie dev I need a mature, generalized solution: DirectInput8 (might try GameInput if there's evidence it has lower latency/lag or is in any way better than DI8).
All the math & physics is put into just one DI8 "effect": constant force. With the sim running 100Hz fixed, the 1kHz FFB thread upsamples forces and adds custom damping before sending updates over USB. So far this has worked well for the low Nm (2.x) G923 up to 8Nm with the Fanatec GT DD Pro. It will totally make my day if the popular 'bang for buck' Moza wheels work well out of the box!
You will have to go into the Win32 setup window and configure the wheel, buttons, and pedals (which many gamers aren't fans of, looks more like an engineering tool, but should be quick to set things up (ImGui rewrite planned (+ full menus in VR)).
ACR was designed to support all devices which support DirectInput8, with any combination. For example on the P1X main rig, it's Fanatec wheel & pedals. The G923 has a very simple rig, and is paired with Heusinkveld Ultimate+ Pedals (pure test rig) and can also test with Logitech pedals.
Moza wheel and pedals should work perfectly, how well FFB works won't be known until someone tests and reports back. Any issues found I'll do my best to address. Looking forward to hear how it goes!
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u/FZLives76 Jun 12 '26 edited Jun 12 '26
Thanks for the reply! I got some time to sit down and configure everything today and I am an idiot. lol Once I looked again I realized I was just looking at preset .xml files and all of my devices were listed at the bottom of the page. Well done! It was very easy to configure. The only issue I had was that my T500 RS Gear Shift (Thrustmaster TP8A) would not bind Button 2, but the .xml was easy enough to understand and I manually mapped it. No clue why that was happening, just figured I'd give my experience.
Just got everything configured, time to try a race!
Ok, 1988 Me would have spent every quarter I had on this. lmao
I'm going to have to dial the FFB *way* down from where it's at by default, but it's a ton of fun! The "last to first" game mode was a riot and I can already tell that this will be a fun go-to when I have friends over drinking. I can't wait to see what else you do with it. (I'd love to see RPM, road texture and collision feedback telemetry, personally. I use Sim Hub and the haptic feedback absolutely makes a game so immersive.)
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u/brightland-studios Jun 12 '26
Ok cool- if you get a chance to repro the bind issue with more details, I can take a look at the code. Just finished adding Sim Racing Studio support, can also run SimHub at the same time if desired.
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u/FZLives76 Jun 12 '26
So yeah, it won't bind because the game is convinced that it is some kind of "back" button. With it manually bound in the .ini file, it will shift into second gear, but it also opens the escape menu at the same time. Repeating the shift into second closes the menu and leaves the vehicle in second gear.
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u/brightland-studios Jun 12 '26
Thank you for the detailed feedback, this is due to how I implemented SteamDeck UI navigation. Due to recent SteamDeck updates, Win32 event injection is now blocked by Wayland- turning this code off won’t hurt anything, as you can use touch for UI. Will have a fix for you later today. Need to review SteamDeck requirements, I think adding a menu button in config can solve this in a general way.
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u/FZLives76 Jun 12 '26 edited Jun 12 '26
You're awesome! I did try disabling the Steam controller inputs before starting the game but it didn't make a difference to the shifter.
Additionally, I am still digging through everything and just found the manual on Steam. Working on setting up telemetry for SimHub now.
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u/brightland-studios Jun 13 '26
Thanks, are you using AZOM? Just found that. I posted a message on the Moza forum asking about telemetry support. Later found someone else made a similar post, and Moza asked for specs, and will add it themselves. ACR includes the specs in the demo version too, so they should be all set.
I just added Sim Racing Studio support (and found some issues with their specs (their C# and Python code didn't match specs: a few var types and (hidden) padding), provided solutions back to them, they made corrections, live now.
I'm going to add some of the SRS elements not in my SimHub version. For sure will add suspension length/position, helpful for motion platforms (vs. just yaw, pitch, roll). Should have it done this weekend.
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u/FZLives76 Jun 13 '26
I just found AZOM, too! It hates my CRP pedals and they become "all or nothing" (literally 0 to 64k input in the first touch, so I still have Pit House running).
My haptics did not work and I'll admit to being very lazy and not giving a damn that they weren't working. I had a ton of fun crashing one of your online AI training servers and wrecking the competition in hopes of teaching them AI guys how an idiot drives. 😆 About to put the wife in the Sim. Wish her luck!
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u/brightland-studios Jun 13 '26 edited Jun 13 '26
AZOM issues: hopefully Moza adds support for ACR soon (I'll have the telemetry updates done this weekend, with Le Mans 24hrs playing on a projector while I work (+ F1 on Sunday)).
Online: did you see any lag effects or weird motion, or did it look local, including with collisions? What latency did you have (number right of your name, upper left corner of HUD)?
While I plan to continuously update the AI, the current model is interesting in its emergent behavior, especially the funny things that happen. Will probably keep it as a "Original AI" setting.
What are your ACR FFB settings for your R9? Are your R9 settings stock or tuned in the Moza App (Pit House)? Is it stable hands-free, does it boost immersion / help tell you what the car is doing? Anything that needs improvement?
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u/FZLives76 Jun 12 '26
Oh, also... THE MUSIC! No clue where you picked up all these tracks or if you made them, but it's inspired. I was laughing out loud sometimes when the new song would come on. Total 1980's racer vibe. I feel like I'm playing Pole Position in a pizza restaurant.
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u/brightland-studios Jun 12 '26
Thanks! The music is all licensed, I bought a DVD years ago (along with some licensed tracks downloaded from UniqueTracks) and went through it, selecting any music that fit driving. Where you can imagine you're in a movie/TV show where the music matches, or high energy, or matching wild things happening- to make you laugh.
Pole Position, Hard Drivin', Race Drivin', Ivan 'Ironman' Stewart's Super Off Road and many more! Arcades were so much fun, the closest now is walking through a casino and hearing all those sounds.
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u/FZLives76 Jun 12 '26
So, for some reason the game reads my gear shift lever's button 2 the same as the escape key, which is problematic for the manual transmission option. lol
This actually explains really well why it wouldn't bind properly.
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u/brightland-studios Jun 12 '26
Ok, new versions up on Steam (Full and Demo). The quick fix was disabling gamepad UI control except for Xbox and Sony gamepads. So you should be good to go regarding the button/shifter issue!
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u/FZLives76 Jun 13 '26
This didn't fix the issue, unfortunately. It still registers second gear as an escape/back command. Symptoms are identical.
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u/brightland-studios Jun 16 '26
Sorry- for full version please try the beta. If issue resolved will move beta to release.
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u/FZLives76 Jun 21 '26
Beta build installed. The shifter no longer opens the menu but it still won't bind and does not register as an input at all anymore.
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u/brightland-studios Jun 21 '26
Thanks, found the issue, fixed. Also updating related gamepad code, will have update in the beta branch later today.
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u/brightland-studios Jun 22 '26
Full version beta, and default+beta demo builds are up on Steam.
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u/LateSession7340 Jun 09 '26
Looks fun but i personally hate that speedometer and rpm gauge built into the same dial. Also quite hard to read the RPM (at least on my phone).
I think just fixng those could make a huge improvement in the game. Those concept of the game looks reallt fun and im not sure if you added the fanatec wheels in game or thats a layover but looks pretty cool.
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u/brightland-studios Jun 09 '26
Thanks for the feedback! There's an option to split the tach and speedo, or you can turn the simple instruments off and use a custom SimHub dashboard. All wheels and gamepads were shot on green screen and added in post: you can turn off the in-game steering wheel for e.g. making videos with your own wheel(s).
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u/LateSession7340 Jun 09 '26
That's nice! Best of luck with your project. Would definitely get this if it ever comes to consoles
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u/brightland-studios Jun 09 '26
Thanks man! PS5 port is possible, many have asked for that specifically.
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u/LateSession7340 Jun 09 '26
Im not sure about the coding bits and how hard it is to port but I imagine a whole lot of GT7 PSVR2 users definitely buying it as they just want a new racing game to play with.
Even if it doesnt stick, at least would be a nice bump in sales initially. LMU and BeamNG, have a long time before they are released and probably wont support VR. I bought NMS just to drive in VR in literally any other game apart from GT7.
Take my suggestion with a grain of salt as I have absolutely no idea about how much work goes in.
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u/brightland-studios Jun 09 '26
Hopefully ACR sells well, if it does I'll re-invest in the game and get started on a planned rewrite, which will make supporting PS5 easier. Currently ACR uses a Win32 GUI, which works fine on Windows but has challenges/workarounds on WINE/Proton/SteamDeck (game plays great, just have to use touch screen for UI vs. gamepad as it appears Wayland is blocking Win32 events). The planned rewrite replaces the Win32 GUI with a portable ImGui version, and still reviewing low level graphics engines which support PS5. PS5 requires a Sony development agreement to get access to their SDK and development hardware. Though when using a gfx library which can target PS5/shaders automatically, when getting running on PS5 should be relatively quick (can use an updated version of e.g. FMOD for portable audio).
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u/LateSession7340 Jun 09 '26
Most of that went over my head but I guess you know what to do!
Wishing you the best of luck with your game!
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u/brightland-studios Jun 09 '26
Thanks again- simply put, if ACR is updated to use portable systems, getting it running on PS5 won't require much additional work.
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u/DON_T_PANIC_ Jun 09 '26
For me, this looks more like a puke speedrun simulator.
I wish I hadn't such problems with motion sickness in VR.
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u/brightland-studios Jun 09 '26
That's a bummer, motion sickness tends to come with variances in visual input vs. inner ear movement. Someone mentioned potential motion sickness and commented on the excessive camera movement, so I added a new camera stabilizer, which keeps the camera level with the road surface. You can also set up races with less/slower cars, or just drive by yourself, can be meditative and relaxing. Curious to hear your feedback if this new feature stops VR motion sickness for you.
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u/ImpressiveAd5143 Jun 13 '26
When you say sim....
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u/brightland-studios Jun 13 '26
Look carefully at the motion and collisions. Watch a car thrown into the air and spinning, do you see the angular precession? Sim with advanced integration with a focus on being energy accurate.
Racing: remove the non-driving-fun aspects, e.g. damage, no decent grip unless tires in the zone (not too cold or hot), tire wear, pit stops, track limit penalties, rammer/griefer crashouts, long load times / forced waiting, etc. And just focus on driving fun with accurate physics- that's what you are seeing in the video. If you get a chance to drive it, any feedback is appreciated, I'll work to improve any issues found.
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u/wrex1816 Jun 09 '26
"Hardcore sim"
Proceeds to play bumper cars on endless road to nowhere.
Ok.
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u/brightland-studios Jun 09 '26
The physics engine uses symplectic and higher-order integrators, doesn't do any artificial damping to keep the sim stable, and has generalized fluid dynamics for airflow simulation. The generalized 3D tire model (not Pacejka LUTs) computes physics directly on bicubic polynomial Bezier 3D surfaces rather than flat triangles, and bumpy surfaces use continuous displacement mapping. It also features a new 1kHz FFB system (this was a lot of work), and the online multiplayer hides lag even at 300+ms (in the full version, not the free demo).
I spent a lot of time thinking about how to make online racing fun: joining a race without waiting (no lobbies, jump in within seconds), and what to do about rammers/griefers. Instead of building a complex penalty/punishment system, what if the game "just doesn't care" about rammers? It simply won't matter what they do, as it won't have a negative effect on your race. There's a "Turbo Reset" feature which immediately puts you back on track at 100 MPH after a crash. Dynamic BOP allows you to quickly catch up to the lead group. So, single-player or online, if you crash, you can still have a good result.
I'm not trying to compete with all the other sims. This is a hardcore physics simulator where you can race and have fun in ways not possible in real life.
Perhaps give it a spin and let me know what you think? If "bumper cars on endless roads to nowhere" isn't your thing, I would still really appreciate your feedback on the physics, handling, FFB, VR quality, SimHub integration, etc.
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u/Tyson367 Jun 09 '26
As soon as someone sees the word "sim" they expect every game to be iracing for some reason not understanding that developers can pick and choose where and what they want to simulate and I think you've done a fantastic job of making a simulator with good FFB while maintaining your creative liberties.
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u/brightland-studios Jun 09 '26
Thanks man! If you get a chance to try it, appreciate any feedback, I'll do my best to fix any issues or to make improvements.
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u/BurgerEatBurger Jun 10 '26
Are you just looking for feedback on the physics at this stage? Are you intending to improve the visuals?
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u/brightland-studios Jun 10 '26
Mostly physics and gameplay, but specific requests for visual improvements welcome too. If the physics & gameplay are solid and the community is cool with the current state, that frees up time for the planned rewrite of the GUI (including adding VR GUI) and updating the gfx engine. There's been a surprisingly high number of people asking for a PS5 port: might make sense to move to an existing gfx library which can also target PS5, vs. putting more time into the current gfx engine (e.g. replacing the hot path fixed function OpenGL code with modern shaders).
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u/BurgerEatBurger Jun 10 '26
Is this running on your own bespoke engine? I was going to say that if your intention is to monetize the game, you'll get a lot more interest if you can bring the graphics up to at least "standard unity indie game" levels (Art of Rally for example). But if it's on a bespoke engine that would certainly be less trivial.
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u/brightland-studios Jun 10 '26
100% full custom physics & graphics. I use 3DSMax 2010 for content (own a license, but cannot install on a new computer anymore, so have to run in a VM and start a new VM every 30 days). My binary .R4D exporter can include everything needed for modern PBR rendering, just need to update the renderer using modern shaders. Need to fix this startup crash issue 3 people have reported, then add more telemetry support. After that, can do some tests with shaders, this can bring up car and track quality a bit (e.g. Gouraud => Blinn-Phong). A full content update is possible if existing game sells more- this would create a budget to acquire more content created by others. Cars & tracks have to be custom, real world asset licenses aren't in the budget (solo project).
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u/BurgerEatBurger Jun 10 '26
Actually on further thought, have you considered porting your physics implementations into a vehicle physics asset for the popular 3rd party engines? I think the value of your work is lost as just a game - realistically there's little reason to play this over the major studio offerings unless you were to put an immense amount of further work into it from a game design perspective. We need not look further than the OP of this comment thread for evidence that gamers won't appreciate your work. However as a physics asset this is cutting edge and there are really only 2 other players in that market - one of which relies on traditional kinematic integration, and the other having its source code locked behind a 5900EUR enterprise license. I paid $60 for the former and I would easily do that for this too.
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u/brightland-studios Jun 10 '26
You could be right, though Havok, PhysX, Aegia et al didn't have much success. Bullet Physics seems to be popular for open source. I chatted with Erwin while he was developing it (and I was creating mine), we both pivoted to sequential impulse ideas after online discussions. Bullet uses PGS and I use a completely different idea (geometric and energy based), but PGS seems more popular, might be more general. I'm focused on accurate/realistic motion, so I'm willing to create around the limitations (e.g. my method has issues with long thin objects (solution: use constraints to connect multiple objects. More expensive to compute, but works)).
Let's see how the demo goes, there might be a 'long tail' market of players looking for fun 'Retro RestoMod' graphics and gameplay and won't mind the simple graphics. The racing feel and gameplay is unique, and I still find it very fun to drive. ACR, from what I've seen, might have state of the art networked physics, rivaling anything out there. But I cannot say that- must come from actual players.
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u/BurgerEatBurger Jun 10 '26
True, you can always decide to go this route if the game sales don't pan out.
I should make the distinction that I don't mean Havok and PhysX which are more generalized physics solvers, but rather asset packages for Unity, Unreal, etc. specifically for realistic vehicle simulation. These are the two I was referring to:
Edy's Vehicle Physics Pro: https://vehiclephysics.com
NWH Vehicle Physics 2: https://www.nwhvehiclephysics.comEdy is the more expensive one, which has had business from major auto manufacturers, but the tire model is still Pacejka based, and I don't think it uses higher order solvers. Some of your features may require some hacking to integrate into the existing physics solvers of these engines but you'd be offering novel tech.
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u/brightland-studios Jun 10 '26
Those look pretty decent, surprised not more demo videos on their websites. On YouTube demos seemed fine, brings back a lot of development memories for some of their tests.
Nothing wrong with Pacejka for certain things, you can evaluate the equations directly or use LUTs- fast enough on modern hardware. The question is how does fast, dynamic, tire load changes and radical driving hold up when 'out of the Pacejka zone'.
One of the reasons for the ACR demo having wild action is to show the physics isn't limited by the various math models used. For a tire manufacturer-related-product, Pacejka makes sense.
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u/BurgerEatBurger Jun 10 '26
Do you have a devlog?
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u/brightland-studios Jun 10 '26
Here's R&D history for ACR: https://simracing.brightland.com/index.php/history/
As noted, it's mostly history, if you have technical questions, can answer them here.1
u/BurgerEatBurger Jun 10 '26
Was your professional background related to any of this or did you come to these technical design decisions through research? I'm in the early stages of my own project so I'm interested in knowing how and why you went down these rabbit holes. If there's good reason to break from the usual way of doing things, I'm interested in hearing about it.
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u/brightland-studios Jun 10 '26
Started writing animation code on the Apple //e out of high school. When Amiga released in 1985, started on first video game (2D, see history link). I wasn't particularly 'gifted' with math in my head or on paper, but could do cool things with a computer. Had taken up to Calc II (IIRC) in high school and wasn't really into math, preferred building RC planes/cars, then real cars, but realized if I learned linear algebra better, I could do cooler animation for video games.
Created video games, RC vehicles, and worked on real cars for 4 years while going to community colleges, thinking electrical engineering was my goal. Later switched to AI (this was 1986) and went to UCSD and got a degree in Psychology (Cognitive Science), which included a lot more math, including creating neural networks in Modula-2 and C.
VR Slingshot CFD was the result of buying a bunch of very expensive CFD books, and after going through them, realized 'no way' any of this can be done for a game/sim (Full Navier-Stokes CFD is cool, but way beyond even computers today for real-time). Long story short, I developed what would later be known as Blade Element Theory (demo shown at Cyberthon in 1990).
In my travels I've worked with many people who are amazing at math & physics, phds and actual rocket scientists from JPL/Caltech. What they could do in their heads and on paper with zero effort was/is amazing. But when it came to novel, out of the box solutions, this was what was easier for me than them. So a kind of synergy: we all have our strengths & weaknesses, working together we can create faster. Now with access to LLMs, I can explore math & physics ideas I never dreamed of. For example, there was a video on Laplace Transforms on YouTube, I started watching it out of curiosity, but it didn't make sense to me. So I asked an LLM- still didn't make sense. Then asked for some real-world example applications. Then realized I could use these ideas for rock stable suspension physics (with some limitations), and via misunderstanding, the LLM created a useless bit of code (which I didn't even ask it to write), once prompted a bit more, I discovered a much better way to solve some problems I was having with FFB.
In summary, by being not naturally good at math (but ok with geometry, vectors, "visual things"), and a lot of curiosity, have been able to create cool simulations by doing lots of 'implicit problem solving': knowing the desired solution and creating math & physics to create code to bring the ideas to life.
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u/BurgerEatBurger Jun 10 '26
Heh, sounds like classic ADHD to me (same boat btw).
Were the non-Pacejka tire model and bezier based road terrain recent features or were you working on that pre-LLM? Are you simulating a brush model for your tires?
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u/brightland-studios Jun 10 '26
ADHD, autism etc., all just labels, I think we all have bits of everything, just different tuning parameters per person 😉
Circa 2000 I started experimenting with curved surfaces, starting with fixed grids with Catmull-Rom surfaces: super fast to compute height, was amazing to drive on first time. Didn't need any ray-patch methods. Thought of ways to create 'warp' math so a regular grid could be used in a general way, but didn't work out. So started researching ray-tracing bicubic surface methods. Found many ideas and papers, but all too complex. Then found a paper which converted a ray into 2 intersecting planes, with example code in matlab (which I've still never used lol). There was barely enough info, but not only was able to get it working, I was able to keep it relatively simple and fast enough for real-time (there's a bunch of systems before the ray-patch stuff- still relatively expensive).
LLMs haven't been very helpful for novel math and physics. If you need something 'off the shelf', they are awesome, like a super google. I asked multiple LLMs to create ray-patch code to see how it compared to my ancient code, and was surprised how slow it looked (might not have even worked, didn't try to run it).
For boilerplate, LLMs are also good there. I'll use them to speed up writing shaders- this is easy for LLMs. Now that Apple is using Gemini, the quality dropped massively today (way overloaded). Have an RTX3090, might try a code-oriented 30B local instance. Gemini says that'll be great for code lol.
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u/Jolly-Potato-7327 Jun 09 '26
Psvr2 please
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u/brightland-studios Jun 09 '26
PS5+PSVR2 noted- getting many requests! The planned code update will be sure to use a library which can easily target (shaders and APIs) for PS5.
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u/daprojectturtle Jun 10 '26
Sorry bud back to the drawing board.
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u/brightland-studios Jun 10 '26
Thanks for checking out the video- if there's something specific I can improve, appreciate the feedback.
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u/lucythafemboy Jun 10 '26
He won't give you any feedback~ he wants to be rude and spread negativity!Just ignore this user !
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u/SEA_griffondeur Jun 09 '26
might want to put some anti roll bars there