Bringing cars from rFactor into GTR2: how?

[MJQT]

I see a lot of people who have converted tracks to and from the various ISImotor sims, and there seems to be a decent amount of documentation available about what is involved and how to do it.

However, I can find very little info on how to bring cars from the original rFactor into GTR2. What is required? Is it even feasible? Is it a massive amount of work?

Things that come to mind are translating physics behaviour, renaming and altering files (e.g. from SFX to AUD), moving from rF1 in-car displays to GTR2 MoTeC-type displays, and creating rain tyres. In particular, since they're both based on ISImotor, it should be possible to faithfully translate the original rF1 physics to GTR2... right?

 

[Zipdrive]

The rfactor mesh file (xxxxxxx.gmt) is not compatible with GTR2 and needs to be opened and then saved in the GTR2 gmt format with 3DSimEd. Not to mention that some material names need to be edited to match those of what GTR2 uses or results in a CTD.

Converting rfactor cars to GTR2 is not like converting GTL cars where you can do it the poormans way and just rename a few files in Windows Explorer. Even some of the physics files need redoing when converting the rfactor cars. GTR2 may use the same gMotor2 game engine but it was rewritten for the type of game that GTR2 simulates.

Even the Race07 cars/tracks need to be opened, edited and saved in the GTR2 format and that's a SimBin product. The nice thing with Race07 is that the physics files are pretty much drop and drive so other than a few optional edit tweaks they work without issues with Race07 to GTR2 conversions.

There are a lot of piss poor rfactor to GTR2 conversions where the individual just did what they had to so the rfactor mod would load in GTR2 without a CTD. Then there are those who basically rebuilt the rfactor car/mod/track from the ground up to work flawless in GTR2. Regardless, both ways need 3DSimEd to do it.

 

[MJQT]

@Zipdrive thanks so much for chiming in!

The rfactor mesh file (xxxxxxx.gmt) is not compatible with GTR2 and needs to be opened and then saved in the GTR2 gmt format with 3DSimEd. Not to mention that some material names need to be edited to match those of what GTR2 uses or results in a CTD.

This makes sense. I was expecting the need to use 3DSimEd due to issues like that.

Even some of the physics files need redoing when converting the rfactor cars. GTR2 may use the same gMotor2 game engine but it was rewritten for the type of game that GTR2 simulates.

I knew the GTR2 devs were using their own modifications on the gMotor2 engine, but didn't know how far it went. Interesting that some of the physics text files need redoing! Out of curiosity, do you know which parts? Tire? Engine torque curves? Suspension geometry?

There are a lot of piss poor rfactor to GTR2 conversions where the individual just did what they had to so the rfactor mod would load in GTR2 without a CTD.

Oh boy. Looking back, I've seen plenty of these too, but didn't know precisely why the GTR2 version was so janky compared to the original in rFactor... now I know

 

[Zipdrive]

Engine curve data is ok, just like gear ratios, it's some of the other engine values that GTR2 looks at differently. The same for some of the other files.

When ever I've converted a car from rfactor to GTR2 I just use a physics package from one of the stock GTR2 vehicles (or a mod with permission) and then tweak it to suit the car I'm converting. I do take some of the entries from the rfactor versions to get it close in performance but the heart of the physics files are good ol GTR2. I remember heat buildup and cooling of the engine and brakes being of different values between the 2 sims.

For a fun test, find an rfactor mod that has a similar car to one of the stock GTR2 cars, say an NGT Porsche or Ferrari. Then swap out the original GTR2 physics files for the rfactor versions and see how the car runs for 20 or so laps. You may have to edit/tweak a few things so as not to get a CTD or have the wheels looking like the car is a monster truck, but it should run and then you can compare the two sets of physics files and see the differences in game and line by line.

I haven't done any rfactor to GTR2 conversions for years so I can't even suggest what mods to play around with so that you can see and feel the differences by doing the physics package swap.

 

[MJQT]

Engine curve data is ok, just like gear ratios, it's some of the other engine values that GTR2 looks at differently. The same for some of the other files.

When ever I've converted a car from rfactor to GTR2 I just use a physics package from one of the stock GTR2 vehicles (or a mod with permission) and then tweak it to suit the car I'm converting. I do take some of the entries from the rfactor versions to get it close in performance but the heart of the physics files are good ol GTR2.

Interesting to know! Thanks for the info.

find an rfactor mod that has a similar car to one of the stock GTR2 cars, say an NGT Porsche or Ferrari. Then swap out the original GTR2 physics files for the rfactor versions and see how the car runs for 20 or so laps. You may have to edit/tweak a few things so as not to get a CTD or have the wheels looking like the car is a monster truck, but it should run and then you can compare the two sets of physics files and see the differences in game and line by line.

Yeah, this would definitely be the most sensible way of doing it. Maybe one mod to study would be something like the rF1 Enduracers Flat6 mod, which is presumably quite similar to the GTR2 NGT Porsche.

 

[Zipdrive]

Maybe one mod to study would be something like the rF1 Enduracers Flat6 mod, which is presumably quite similar to the GTR2 NGT Porsche.

Yeah, the idea is not to make it exactly like the stock GTR2 car physics but to see how unchanged (not including required edits) rfactor physics perform in GTR2 with a similar car.

Use and rename all the physics files.

hdv --> hdc
tbc --> tyr
pm --> sp
engine.ini --> engine.eng
gears.ini --> gears.grb
damage.ini --> damage.dmg
sfx -->aud (optional if your going to use the rfactor sounds)

Also don't forget to edit the various entries in the new HDC file to use the other newly renamed rfactor physics files. You could leave some of the names as is but I'm old school and like to keep everything GTR2 friendly.

It will take a bit of file tweaking but it's a great way to learn.

I have a lot of respect for those individuals that can scratch build or super tweak the physics files from one gmotor2 game to the next so that the mod performs the same regardless of what sim your using it in.

 

[The Iron Wolf]

Yeah, the idea is not to make it exactly like the stock GTR2 car physics but to see how unchanged (not including required edits) rfactor physics perform in GTR2 with a similar car.

Use and rename all the physics files.

hdv --> hdc
tbc --> tyr
pm --> sp
engine.ini --> engine.eng
gears.ini --> gears.grb
damage.ini --> damage.dmg
sfx -->aud (optional if your going to use the rfactor sounds)

Also don't forget to edit the various entries in the new HDC file to use the other newly renamed rfactor physics files. You could leave some of the names as is but I'm old school and like to keep everything GTR2 friendly.

It will take a bit of file tweaking but it's a great way to learn.

I have a lot of respect for those individuals that can scratch build or super tweak the physics files from one gmotor2 game to the next so that the mod performs the same regardless of what sim your using it in.

Do you happen to know how above files were named in F1C (which is ancestor of both rF1 and GTR2)? I am under impression that GTR2 changed from rF1 mostly in graphics, but rF1 evolved further after GTR2 work started. Most notably, rF1 has physics and graphics on separate threads, so physics rate is independent of framerate. Don't quote me on that, those are just my guesses coming from my plugin work (GTR2 plugin model is identical to rF1 plugin model, which suggests code mostly stayed the same).

 

[Zipdrive]

F1 2002, F1C, NASCAR Thunder 2003 & 2004 gMotor1 sims all use the same physics file names as rfactor.

The original SimBin FIA GTR physics file names are the same as GTR2.

I don't know the inner workings of rfactor, or GTR2 for that matter, so can't give you any info there. It could be that with GTR2 focusing only on GT type physics and rfactor having a wider variety of stock vehicles and physics from GT Style Racing to Open Wheel it's possible that ISI could have updated their code to allow the physics to be on a separate thread. This would allow room for future physics types in the code without much if any performance hit.

 

[MJQT]

Yeah, the idea is not to make it exactly like the stock GTR2 car physics but to see how unchanged (not including required edits) rfactor physics perform in GTR2 with a similar car.

Ah! I see. So you can literally figure out where rFactor physics files go janky in GTR2. Got it. Thanks for the clarification

Related to how I misinterpreted Zipdrive's comment, though – anyone know mods that were released by the original creators for both rFactor and GTR2? I can think of tracks where this was the case, but not cars. If such mods exist, might be helpful in learning from experts who knew what specific changes needed to be made.

F1 2002, F1C, NASCAR Thunder 2003 & 2004 gMotor1 sims all use the same physics file names as rfactor.

Oh wow! NASCAR Thunder on PC was ISI-based too? Holy crap... I had no idea. I played the living crap out of that game back in the day. Had no idea I was playing on gMotor! EDIT: off topic, I know, but I couldn't help myself

 

[Zipdrive]

Ah! I see. So you can literally figure out where rFactor physics files go janky in GTR2. Got it. Thanks for the clarification

Exactally my friend.

That's why the rfactor mod you mentioned as a NGT Porsche replacement would be a great live test and learning experiance for how to tweak and edit rfactor physics files so that they not just work in GTR2 but work well. The bonus is that those fellas have made good rfactor mods so the physics package for their Porsche should also be close to the real thing.

I'm not familiar with any modder who has made their vehicle mod for both rfactor and GTR2 other than BorekS. I have found that those that made mods for rfactor, because of it's more versatile physics, mainly stayed with the ISI flagship. I think rfactor central is still online and it use to list the mod's author. There maybe a name that rings a bell.

Oh wow! NASCAR Thunder on PC was ISI-based too? Holy crap... I had no idea. I played the living crap out of that game back in the day

Yep and NASCAR Sim Racing as well. I currently have that one installed with some fixes I made so that it looks a little better on the more modern hardware. Mainly the LOD changes at further distances. Having the bodies and wheels change back and forth from Lod A to Lod B and then C in a matter of a few car lengths was getting to me.

 

[The Iron Wolf]

because of it's more versatile physics, mainly stayed with the ISI flagship

Other than physics/FFB decoupled from the framerate, can you give specific details how exactly rF1 is more versatile in terms of physics? Not saying it isn't so, just learning and taking notes for my own education.

 

[Zipdrive]

David Wright would be the fella to try and get more in depth info from regarding GTR2 physics. I believe he knew/knows some of the SimBin fellas and could easily debunk or confirm what I have mentioned. I can only go by what I've personally tried and have driven over the years on those two sims and there is a difference in the physics engines. How much so on the core level is above my pay grade.

As for rfactor being more versatile all you have to do is compare various mods on both sims. rfactor seems to do the various racing types well (minus the AI needing work), where as GTR2 does GT type racing great, yet off road and even oval racing on GTR2 fall behind. Why ? Easy, the core physics of GTR2 have been tuned for GT style racing. Try getting a GTR2 Off Road mod airborn on the track, and I don't mean flying though the air after a crash, LOL. In rfactor it's not a problem to get a little air. Why can it be done in rfactor and not GTR2 ? Because rfactors physics are more versatile and not locked to a specific style of racing.

If someone can point out my being wrong please chime in and straighten me out. Haven't had a good straighting for a while

I don't use GTR2 for any racing types other than GT style racing, which is my personal favorite anyways. For other types of racing, be it oval, off road, kart I always used rfactor because any GTR2 conversion I found did not feel/handle the way it did on rfactor, regardless of how good the converted physics were, what settings I used or FFB I had set, and believe me I tried many different settings.

Found this thread Iron Wolf https://www.racedepartment.com/threads/handling-in-gtr2-versus-rfactor.182467/ Seems to debunk my findings somewhat but I stand by what I've wrote. I'm too stubborn not too.

 

[jgf]

........There are a lot of piss poor rfactor to GTR2 conversions where the individual just did what they had to so the rfactor mod would load in GTR2 without a CTD......

LOL!

Auto Union from rf GP37 mod (my repaint):

Auto Union from GTR2 conversion (note also square brake "discs" on Alfa in background):

I wonder if it's even feasible to salvage this mess.

Cockpit view of tires, imagine them rolling:

 

[The Iron Wolf]

David Wright would be the fella to try and get more in depth info from regarding GTR2 physics. I believe he knew/knows some of the SimBin fellas and could easily debunk or confirm what I have mentioned. I can only go by what I've personally tried and have driven over the years on those two sims and there is a difference in the physics engines. How much so on the core level is above my pay grade.

As for rfactor being more versatile all you have to do is compare various mods on both sims. rfactor seems to do the various racing types well (minus the AI needing work), where as GTR2 does GT type racing great, yet off road and even oval racing on GTR2 fall behind. Why ? Easy, the core physics of GTR2 have been tuned for GT style racing. Try getting a GTR2 Off Road mod airborn on the track, and I don't mean flying though the air after a crash, LOL. In rfactor it's not a problem to get a little air. Why can it be done in rfactor and not GTR2 ? Because rfactors physics are more versatile and not locked to a specific style of racing.

If someone can point out my being wrong please chime in and straighten me out. Haven't had a good straighting for a while

I don't use GTR2 for any racing types other than GT style racing, which is my personal favorite anyways. For other types of racing, be it oval, off road, kart I always used rfactor because any GTR2 conversion I found did not feel/handle the way it did on rfactor, regardless of how good the converted physics were, what settings I used or FFB I had set, and believe me I tried many different settings.

Found this thread Iron Wolf https://www.racedepartment.com/threads/handling-in-gtr2-versus-rfactor.182467/ Seems to both confirm and debunk what I've mentioned.

Thanks for the thread. My impression is based on both telemetry and driving is that it is all up to how cars are configured. I found some GTR2 F1 cars to handle very similarly to how good ones (by me) do in rF2 (I have to admit I never got into rF1 deeply due to absence of rain). But, yes, many many cars handle awfully, but again it always felt like specific mod issue, not engine issue which seems to be extremely similar especially in physics. And I tried many F1 mods in rF1 (and even rF2) that drive entirely awful.

I always promise myself to not discuss physics without numbers and equations and keep breaking my promise ... all I say is subjective of course.

EDIT: and I see David confirmed my subjective observation: 99% same physics engine + new options for stock cars and more configuration values exposed.

 

[jgf]

..... Try getting a GTR2 Off Road mod airborn on the track,....

Not off-road, but I've gotten F1 cars airborne in GTR2; the last two hills at the old Sachsenring are deadly due to a slight curve at the crest of each. The cars understeer horribly when not on the ground.

 

[Zipdrive]

Not off-road, but I've gotten F1 cars airborne in GTR2; the last two hills at the old Sachsenring are deadly due to a slight curve at the crest of each. The cars understeer horribly when not on the ground.

When I'm mention airborne I mean like this

.

Myself and others have tried to get GTR2 to do it as I made Off Road mods and others have made some off road tracks, both like in WCORR and the tamer off road tracks from ToCA3

I've had the steering go lite in GTR2 when the front wheels make less contact with the track when I've gone over an exaggerated bump or hill but I have never seen a car fully leave the track.

As for that beaut of a conversion it looks like whoever done it only used the low (far distance) LOD meshes. Compare the rfactor GEN file to the GTR2 CAS file or post them somewhere and I'll have a quick peek to see if it's just a bad edit.

 

[Bjarne Hansen]

EDIT: and I see David confirmed my subjective observation: 99% same physics engine + new options for stock cars and more configuration values exposed.

That is the same % difference that there is between chimpanzee and human DNA

I would agree with zipdrive that gtr2 are more limited in the car physics than rf1/AMS but does GT cars better than rf1 does.

One thing I adopt are BumpStopRisingSpring and BumpStopRisingDamper for each wheel or the rf1 conversion are jumping up and down and even the AI have issues driving the cars.

In general I find lighter cars are not behaving and feeling as great in Gtr2 as in rf1/Ams.
Maybe I do not know how to make the physics but I have also not tried a lighter mod type that was as great in Gtr2 as in AMS.
Doesn't mean they can't be good fun but it isn't same detailed physic feel to them.

 

[MJQT]

I've had the steering go lite in GTR2 when the front wheels make less contact with the track when I've gone over an exaggerated bump or hill but I have never seen a car fully leave the track.

This is really interesting, as it squares with a couple things I was observing the other day while driving the 2016-17 Trackaholics GTR2 Aussie Supercars mod the other day back-to-back with the AMS Super V8 and V8 Factor in rF1.

You know how V8 Supercars often get up on two wheels after hitting a kerb hard?

I could do it in AMS and V8 Factor, but I couldn't get GTR2 to do it... instead, in GTR2, the car just bounced/shook violently and got all light seemingly on both sides of the car after me trying to hit the kerb only with two wheels on one side of the car. I figured I was driving weirdly somehow, or the mod's physics were somewhat incorrect. But maybe it's GTR2's fault?

This is also related to my original question, because I was thinking about whether it would be worth it to learn all this 3DSimEd and physics stuff to bring a Supercars mod like V8Factor into GTR2 (if I could get permission). Since GTR2 has rain and allows driver swaps and saving races in single player – which would be super cool when doing a mock Bathurst 1000 or Gold Coast 600 or whatever. But this would throw a serious wrench in that plan.

EDIT: Has anyone else been able to get a Supercars mod up on two wheels in GTR2?

 

[The Iron Wolf]

One thing I adopt are BumpStopRisingSpring and BumpStopRisingDamper for each wheel or the rf1 conversion are jumping up and down and even the AI have issues driving the cars.

Good points. Suspension stuff might feel different because of physics update rate. At some point in the future, I will likely attempt decoupling player physics from framerate in my plugin (low priority thing, however). But you say even AI behaves differently, so maybe there are deeper tweaks somewhere. In any case good info here.

 

[jgf]

......

As for that beaut of a conversion it looks like whoever done it only used the low (far distance) LOD meshes. Compare the rfactor GEN file to the GTR2 CAS file or post them somewhere and I'll have a quick peek to see if it's just a bad edit.

No idea what i'm looking for,so here are files for Auto Union; other cars have similar issues (the ERA cockpit view shows no front brake drums or spindles, just tires and rims floating there).