More realistic cars for ROR? Explanation, tips and demo vehicle

masfilip

I just like Rigs of Rods.
Joined
Aug 26, 2018
Messages
13
Location
Prague, Czech Republic
#1
Hello,
I have been thinking about this for a long time and now we can discuss it.

Everybody who plays ROR feels, that sometimes cars in ROR doesn´t drive as easy as in other games. I started thinking about this long time ago and there can be many factors that contributes to this fact. It could be caused by ROR itself, or by the way that authors build their cars. When I look at most of the cars in ROR, I think it can be improved if authors do some things little different.

Because this may be very difficult to understand, I also built special "test car", which takes my thoughts into practice and you can download it below. It should be car very similar to my Mazda 626 1.8, FWD family sedan with front and rear Mc Pherson axle.

Now I will try to quickly explain most of this vehicle´s truckfile. As I mentioned, I tried to do something that matches to my real car in terms of driving characteristics and performance, so don´t look at deformation, which is not completely perfect. In terms of crashing, it is similar to Gabesters cars, so it has deformable and openable doors and hood, but that doesn´t really matter.

So to start, beginning of this vehicle is similar to other cars... I will skip some sections and only explain important sections, where I applied my thinking.

First change comes at engoption section. Here I have very low engine inertia, so you can rev car on neutral and engine RPM will rise and drop realistically. Clutchforce is also very low, but that is nothing new when you build car in ROR. Then comes minimass section, that defines the least possible weight of node, which may be very useful when you try to do realistic very light wheels. Torquecurve section is good for making realistic engine characteristics and for realistic acceleration.

Code:
engine
;min rpm, max rpm, torque, differential ratio, rear gear, neutral, first, second, third, fourth, fifth, sixth...
3800.0, 5280.0, 145.0, 3.619, 3.166, 1.000, 3.307, 1.833, 1.310, 0.970, 0.755, -1.00

engoption
;inertia, type, clutchforce, shifttime, clutchtime, postshifttime, stallRPM, idleRPM, maxIdleMixture, minIdleMixture
0.014, c, 90, 0.55, 0.55, 0.55, 400, 800, 0.48, 0.1

minimass
0.5

torquecurve
0,0
600, 0.80
1000, 0.82
2500, 1.00
4000, 0.96
5500, 0.78
6600, 0.56
Then we have nodes and beams section. There is nothing special, just try to think about weight distribution in real car, which is really important.
For Beams, I use values like:
Code:
set_beam_defaults 3000000,  80,    40000,  99000000, 0.02, tracks/beamblack, 0.45
which are good for stability with +-4 kg nodes. But this depends on how light or heavy is node, so here you need to know basics of weight tuning. So that is same as building other cars in ROR. Very important is last number, which defines elastic deformation of beam - more here: http://docs.rigsofrods.org/vehicle-creation/fileformat-truck/#beams

So if you skip that super long nodes and beams sections, you get to meshwheels section. Here you must set right beam_defaults, so you can easily do very light wheels, which makes driving more realistic. To do this, they shouldn´t have too high sping and damping:
Code:
set_beam_defaults 400000, 100,  2500000,  3000000, 0.02, tracks/beamblack, 0.0
meshwheels2
;tyre_radius, rim_radius,width,numrays,node1,node2,snode,braked,propulsed, arm, mass, spring, damping, side, meshname material
;front
0.30, 0.0, 0.28, 16, 63, 64, 9999, 4, 1, 67, 15.0, 104000.0, 200.0, r, wheel.mesh tracks/trans
0.30, 0.0, 0.28, 16, 67, 68, 9999, 4, 1, 63, 15.0, 104000.0, 200.0, l, wheel.mesh tracks/trans
;rear
0.30, 0.0, 0.28, 16, 82, 81, 9999, 1, 0, 77, 15.0, 104000.0, 200.0, r, wheel.mesh tracks/trans
0.30, 0.0, 0.28, 16, 77, 78, 9999, 1, 0, 82, 15.0, 104000.0, 200.0, l, wheel.mesh tracks/trans

axles
w1(63 64), w2(67 68), d(s)
I think this setting is pretty good, wheels are light, but also feel like having enough grip, which is very important for good and easy driving.
Then I put axles section, which is normally used for cars: http://docs.rigsofrods.org/vehicle-creation/fileformat-truck/#axles
So if you skip these shocks, command and hydros stuff, last important stuff is fusedrag: http://docs.rigsofrods.org/vehicle-creation/fileformat-truck/#fusedrag
Code:
fusedrag
0, 16, 0.32, NACA0009.afl
Fusedrag helps you to reach higher top speed, and that may be helpful when you have realistic acceleration but slower car.

And so, thats it ;) I hope that we will have more realistic cars in ROR. But these small improvements may be also useful for big vehicles, like trucks or buses.
Also, if you want to use this example vehicle for your project, it is OK, just let me know. I will be happy if it helps you :) And if you have any tips or ideas, let me know.

By the way, in zip are actually two test vehicles - they are almost same, but one has normal meshwheels and second one has flexbodywheels, which are more realistic but they may affect FPS because they are more complex.
 

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