[WIP] Jaguar XJ13 1967

Discussion in 'Vehicles' started by mantasisg, Nov 26, 2018.

  1. mantasisg

    mantasisg Registered

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    Thank you all for helping a lot, I did it all and more, and it is pretty much same stuff. Though I haven't tried to addapting whole other mod as placeholder and then changing bits, but i think it is little different from how it is now.

    I wonder could deformable tires be a problem or something, ps I haven't checked yet if the GT40 mod has tires flexing.

    And I have got some better insight into issue. Seems like game doesn't crash now as i disabled the FFB, or perhaps other things helped. But the issue remains. But now I am able to call a replay right at the beginning and check whats happening and how car looks. First of all car is for some reason turned 90degs to the left, and next issue is that it has no TIRE, SPINDLE, DEBRIS objects on it.

    I have also opened .veh file with 3Dsim and it opens model nicely. The Y axis is pointing left, and should be pointing backwards. Perhaps if i will rotate the car or change axis on export it will work, have to try it now.

    I am also renaming a lot of objects, for example lf_TIRE to tire_lf and so on...

    EDIT:

    GOT IT !!!! it was mostly naming issue I think. Fixed names and axis and have it in game.
     
    Last edited: Nov 29, 2018
  2. Bjørn

    Bjørn Registered

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    Sounds great, dawg!

    Now, show us ;)
     
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  3. mantasisg

    mantasisg Registered

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    I would love to show it now, but I can't figure out some stuff.

    First is that body paint is not reflective which is weird because the very first time when I launched it and when it had no wheels and body was rotated it was very reflective right from the scratch, and I can not make it like that again.

    Second is that I can change specularity settings in DevMode, but it doesn't seem to get saved, so i suppose I have to write down values and re-apply them in gJed.

    Third issue is that some meshes aren't visible from cockpit or from exterior. At first interior objects were invisible from exterior camera, they were under instance "COCKPIT", I changed instance to "BODY_IN", and now it is not visible from interior camera, but visible from exterior.

    I wish there was some documentation about how to name objects, and how to name instances and how to use them.

    EDIT:

    Seems like I understood that you have to have object in cockpit and in bodyin instances if you want to have them visible from interior and exterior cams. Now I noticed that my engine elements aren't visible from interior cam.

    I am pretty much only fighting for body paint reflections now, my main goal at the moment, couldn't solve it yet.

    EDIT AGAIN:

    In gJed I noticed that reflections appear when there is no diffuse, or in other words in night. For some reason diffuse cancels reflections for me.

    EDIT haha:

    Nope in game it is unreflective even in darkness, though it is interesting how windshields stay reflective in night like if it would still be a day...

    MORNING EDIT :D Solved car being unreflective ! It was caused by "skin" in teams folder... one problem stays - reflectivity is full blown at night.
     
    Last edited: Dec 1, 2018
  4. mantasisg

    mantasisg Registered

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    Ok, I have finally something that is "something" in game, to be more precise in devmode. I still have to improve and tweak a lot of things to reach the basic level for the model. It is a bit annoying when I don't really get how material tweaking values in dev mode works, I am confused once it seems to be different from gJed, then it seems different from how it was last time tweaked in devmode, and I have to tweak them every single time I launch devmode, I'm not going to have good results this way.

    Here are some acceptable screens from Devmode:
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    I still have big issue with reflectivity, it is just wrong when there is no lighting. It is already a bit bright in shadows, but when sun goes down it progressively looks worse, and in night is absolutely wrong, any ideas what could be wrong ?

    [​IMG]
     
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  5. Bjørn

    Bjørn Registered

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    Which shaders are you using for the carbody? I don't use GJED myself... I am a 3Dsimed-'noob' :) If you use the material menu in devmode you can play around with the values and get what you'd like to see in-game, note down the numbers and plot them into GJED or 3Dsimed/3DS MAX, save the GMT and it should stay like that until you save the GMT again with different shader settings...

    EDIT: And yes, most "correct" shaders for body use as of right now (with future released shaders it might change) the reflectiveness is controlled with the alpha channel of the textures.
     
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  6. mantasisg

    mantasisg Registered

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    I use car body shader. There is also other car body shader with more stuff in it, but that shader didn't work for me nor in gJed nor in devmode, it basically used normal map for diffuse...

    And I did exactly that, I wrote down values from mats in devmode as i was adjusting them, then applied those values to gJed saved gmt, opened devmode, and values were different.

    I know that reflections are controled by diffusion texture alpha channel, but it doesn't explain to me why reflections blows out in darkness, look at windows, it is same with them. It is also like that in gJed, though in gJed car is not reflective in the day at all, but it gets reflective in darkness, though in gJed it looks right at that point.

    That actually body paint + damage shader, because it gets kinda redirected to this when I take body paint shader. In general in devmode car looks ok in day, and in gjed it looks ok in night :D

    [​IMG]
     
    Last edited: Dec 1, 2018
  7. Bjørn

    Bjørn Registered

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    I use "car body paint + damage + rain" I haven't really paid that much attention to reflections and the differences in day and night environments... I will from now on, see if I can spot or recreate your issues

    You've come a long way though - big ups for that. rF2 graphical engine is a bit of a dinosaur, we can't deny that I think - it could be a weak point... But I'm sure you can find a setting that suits both day and night - you know, a better compromise. The reflections seem to be stronger at dusk, like before it gets really dark, right... But I must admit I haven't paid much attention to it - but I will now.
     
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  8. mantasisg

    mantasisg Registered

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    Yeah I think rF2 engine is old and have a few places where it could be better. But I don't think that it is obsolete, in many ways I think it is better than A LOT of other games/engines. For example I absolutely love how the light works, how the world gets illuminated, how many options and flexibility there are. Luminance is probably something I love the most in rF2, it is so alive, everything counts: which direction you look, the sun position, whats the sky like, headlights and lamps... In other games it is so apparent how luminance is so static, but in rF2 it appears to be simulated, and quite well. A friend came a week ago, and he is very much into games, I pointed out to him how the track illumination is alive in rF2, and he agreed, he said that it is perhaps best that he seen in games, because it just looks right, we drove in Oulton Park, which looks super well. We ofcourse didn't deny that it is nowhere near GTSport for example, but we are conscious enough to understand that it is not simulated graphics, but prebaked lighting...

    I saw iRacing announcment of dynamic day/night transitions today, the luminance doesn't appear to be simulated, at least seems that it is the "flat" diffuse power way + angles of specularity. But I really like dynamic cloud shadows thats a big deal IMO. I saw option of clouds casting shadows in rF2 as well, or sparks, but seems like it is disabled now. I think rF2 is a bit weaker when it comes to shadows and reflections, I wonder if it could be improved with raytracing technology, I wonder if it would be possible to implement to rF2 engine. AFAIK rF2 engine is very scalable, but how much ? S397 really did great job opimizing it, it is great now ! Though I don't use max settings, I find the looks of rF2 really good, perhaps lacks some candy here and there, but it looks true to me, but artists has to do a good job to really pull the potential.

    I find rF2 super realsitic from onboard view at real time. It doesn't look as well from exterior cams or/and in stills. Speaking of cameras, it is weak point of rF2 for sure, with more control it could make the exterior view look much more appealing, also would enable being "photography simulator", those nice screenshoots does help a lot.

    Bwoah... after all this... I have to add that my night reflection issue is probably not graphics engine related at all, must be something off. Perhaps it would be best to wait a bit more for new paint shader, I like how it looks in recent preview.
     
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  9. KittX

    KittX Registered

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    The shader most likely is set up wrong.
     
  10. mantasisg

    mantasisg Registered

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    I am having great fun with physics now. Looks like there are so much things and so much posibilities and it is actually quite pleasant to work on. I am not vehicle dynamics expert, but I do have some interest in it, I am also structural engineer so I am slightly familiar with physics, mechanics... So maybe I can do something. Though I would be glad to share the work with someone who would like to, and has good understanding and knowledge.

    I am very happy that such website exist: http://meetme.bplaced.net/rF2_onlineTools/ISI/PhysicsGlossary.htm#HDV
    also with some tools http://meetme.bplaced.net/rF2_onlineTools/. I am having great time reading it.

    Yesterday I was driving the car a lot, tweaking a lot. I felt the car is absolutely not twitchy, I have set inertia box randomly, just randomly making it smaller. Today I have decided that it would be better to use 3D model to determine how the inertia box could actually look like, and I have got much smaller box than I guessed.

    Look, do you think this mass distribution box make sense ? The very rear is basically only body shell, and at the front there is a radiator, so it pushes mass distribution a bit. Sides are cut a little bit because there is relatively little mass too, and the top is obvious.

    [​IMG]
     
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  11. Bozak

    Bozak Registered

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    It does not make a noticable difference if you make just a bit smaller the car, weight is more noticable and CGHeight.
    Use the calculate inertia button at rF2 online tools and be done with it.

    Another great site for physics by yoss here
    Also S397 Development Blog
     
  12. philrob

    philrob Registered

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    mantasisg,
    using these figures i make the inertia to be:
    Wheelbase 2,410 mm (95 in)[1]
    Length 4,810 mm (189 in)[1]
    Width 1,800 mm (71 in)[1]
    Height 1,000 mm (39 in)[1]
    Curb weight 998 kg (2,200 lb)[1]

    Mass=1068 // all mass except fuel including 70 kg driver
    Inertia=(2148.1, 2347.5, 377.4) // all inertia except fuel
     
  13. mantasisg

    mantasisg Registered

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    Thanks for the blog link, a lot of interesting things to read. Another link is exact same site like I already used haha
    To me it seems like inertia does difference, especially when driving on the limits, and it should be that way, mass distribution should be very important.

    Thanks, but thats not really right. Mass distribution is usually not equal to overall dimensions of a car. There is indeed some mass everywhere from the tip to the tip, but if you'd chop ~40cm from the rear end of my car like a cake it would be not heavy. Then if you'd chop and weight next ~40cm, where engine bits starts and more, then it would be really heavy. Though when mass is two times further it has four times more inertia, you still have to make a good guess to approximate it to the shape of a box.
     
  14. philrob

    philrob Registered

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    Mantasisg,
    Yes i agree with your suggestion of using an box to approximate the Inertia and that is what most programs and indeed this one do.
    However they do not chop bits off and make it a reshaped box, just a shorter or narrower box.The programs to work this out
    also do not take into account engine, fuel tank positions.( non that i know of)

    We do have within RF2 a way to tell the Engine where the mass is located and where the fuel tank is.

    Porsche 956 rear engined like the XJ

    FuelTankPos=(0.0, 0.24, -1.20) // location of tank relative to center of rear axle in reference plane

    Mass=936
    Inertia=(970,1298,328)
    CGRearRange=(0.590, 0.00, 0) // fraction of weight on rear tires


    Skip Barber RF2 rear engined

    FuelTankPos=(0.0, 0.15,-0.65)
    Mass=629
    Inertia=(628.43,680.62,112.5)
    CGRearRange=(0.604, 0.001, 1)

    RF2 has another parameter for fuel tank
    which might be worth looking into

    FuelTankForceDistrib=(0.4:front_subbody:(0,0,-0.18),0.6:rear_subbody:(0,0,0.18) Skip Barber
    i would be very interested if you find a means of doing this.
     
  15. mantasisg

    mantasisg Registered

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    Yes the cars are rear mid engined.

    In terms of inertia it doesn't matter if it is an engine or a piece of led, or something metal unrelated at all, everything is just mass that needs to travel around certain axis. I don't know why fuel tank inertia is separate, maybe to interpolate it with fuel load ?

    Interesting stuff with [FuelTankForceDistrib] parameter. I think it is pretty clear what it does. It is meaningful for me as fuel tanks are centered to the chassis. Also the fuel tanks are on the sides, I wonder if I could tell rF2 that there are two tanks, one on the right side, and one on the left side.

    I suppose you checked MAK Corp 956 inertia values. If you'd check what values would be with actual car dimensions you would be surprised
     
  16. Emery

    Emery Registered

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    If you calculate the inertia for the two full tanks, you'll find that it is different than a single tank because of their distance from the center, thus there's no reason for rF2 to know that there's two tanks when it comes to inertia (unless you're drawing fuel from only one tank at a time which, considering their location on the sides, would be a bad idea for a race car). Yes, it's an extra step to calculate two inertias and combine them.

    If you want a more precise inertia calculation for whole car (gearbox, engine, battery, driver, etc), here's an Excel spreadsheet that can help: http://www.car-engineer.com/vehicle-inertia-calculation-tool/ (link for spreadsheet is Excel symbol at end of article). All you need are the mass of each item and their XYZ coordinates.
     
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  17. philrob

    philrob Registered

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    Emery,
    many thanks for this, i have never found a spreadsheet as good as this one before.Something else i will have to try and work out, to go with hundreds of other parameters.
     
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  18. mantasisg

    mantasisg Registered

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    Calculating every little bit of vehicle is a bit of overkill, maybe would be useful at the very high precision level such as for professional racing teams, and still IMO they would make a lot simplifications, because thats just how it is in engineering.

    Today I learned one thing. NominalMaxSteeringTorque does not set higher steering torque with higher value, but the opposite happens. It pretty much scales the torque to FFB. It is a bit confusing, as explanation is saying: "Maximum steering arm torque to effect force feedback strength". I don't completely understand it, but I understand that practically FFB is much heavier with value on 5 than on 20. Does it mean that it sets the refference torque from which FFB begins to be developed, but maybe then it should be "minimum" in explanation, rather than maximum ? Or does it simply set steering torque which should make full 1:1 effect on FFB ?
     
  19. MaD_King

    MaD_King Registered

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    Yes I confirm ;)
     
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  20. Bozak

    Bozak Registered

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    In DevMode drive the car and click ctrl+V, at the lower left of your screen you will see a value of RawStr=xx.xxNm
    As you drive this number will go up when there is strong FFB. The highest number that you see is the one to use for NominalMaxSteeringTorque=xx at controls-hdv.

    There are more combination with ctrl+ other letters in devmode, just try to find them :)
     
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