Project Universal Cars for Orbiter (UCFO) Development Thread

Can you print output that shows the values of empty_mass, max_front_weight, and max_rear_weight? I think they need to be explicitly passed to the function in C++, but I could be wrong.
 
Thunder Chicken said:
Can you print output that shows the values of empty_mass, max_front_weight, and max_rear_weight? I think they need to be explicitly passed to the function in C++, but I could be wrong.
Click to expand...
Give me a second.

Starts pressing random keys
EDIT: I'm going to re-read the XR5 source code, because it had compression in the landing gear and I think it might work.

EDIT2: Oh God...
Code: 
**** /tmp/Orbiter.log
000000.000: Finished setting up render state
000000.000:
000000.000: **** Creating simulation session
000000.000: VSOP87(E) Sun: Precision 1.0e-06, Terms 554/6634
000000.000: VSOP87(B) Mercury: Precision 1.0e-05, Terms 167/7123
000000.000: VSOP87(B) Venus: Precision 1.0e-05, Terms 79/1710
000000.000: VSOP87(B) Earth: Precision 1.0e-08, Terms 2564/2564
000000.000: ELP82: Precision 1.0e-05, Terms 116/829
000000.000: VSOP87(B) Mars: Precision 1.0e-05, Terms 405/6400
000000.000: VSOP87(B) Jupiter: Precision 1.0e-06, Terms 1624/3625
000000.000: VSOP87(B) Saturn: Precision 1.0e-06, Terms 2904/6365
000000.000: SATSAT Mimas: Terms 113
000000.000: SATSAT Enceladus: Terms 33
000000.000: SATSAT Tethys: Terms 101
000000.000: SATSAT Dione: Terms 59
000000.000: SATSAT Rhea: Terms 68
000000.000: SATSAT Titan: Terms 100
000000.000: SATSAT Iapetus: Terms 605
000000.000: VSOP87(B) Uranus: Precision 1.0e-06, Terms 1827/5269
000000.000: VSOP87(B) Neptune: Precision 1.0e-06, Terms 391/2024
000000.000: Finished initialising world
000000.000: 3CV: FrontLeftWheelID: 8
000000.000: 3CV: FrontRightWheelID: 7
000000.000: 3CV: RearRightWheelID: 14
000000.000: 3CV: RearLeftWheelID: 13
000000.000: Finished initialising status
000000.000: Finished initialising camera
000000.000: Finished setting up render state
000000.000: empty_mass: 500.00
000000.000: max_weight_front: inf
000000.000: max_weight_rear: -inf
000000.000: Finished initialising panels

000000.000: empty_mass: 500.00 Correct
000000.000: max_weight_front: inf ?
000000.000: max_weight_rear: -inf ?

Apparently the values are going to infinity...
 
Last edited:
Well after initializing the variables in the constructor I no longer have infinite values (how did I forget?).
Screenshot_2025enero03183840.jpeg
But now the car sinks, but at least it no longer does CTD or segfault.

This is the result of the Orbiter log:
000000.000: empty_mass: 500.00
000000.000: max_weight_front: 266.42
000000.000: max_weight_rear: 5131.96


Clearly there is an imbalance, what could it be?
 
Matias Saibene said:
Well after initializing the variables in the constructor I no longer have infinite values (how did I forget?).
But now the car sinks, but at least it no longer does CTD or segfault.

This is the result of the Orbiter log:
000000.000: empty_mass: 500.00
000000.000: max_weight_front: 266.42
000000.000: max_weight_rear: 5131.96


Clearly there is an imbalance, what could it be?
Click to expand...
The empty mass is in kilograms, but the weight is in Newtons. 500 kg * g ~ 4905 N. The total maximum weight obtained in
ClbkPostCreation should also include fuel weight, which should explain why the sum of the front and rear weights is ~5400 N.

Does the vessel remain level while it sinks? From the front and rear weights it seems that the CG of the vessel is pretty much on top of the rear axle.
 
I just saw the picture of the setting of the car. The only thing that jumps out at me is that you may have set the front wheel contact points at the level of the front wheel axles. The rear wheels look like they are set appropriately.
 
Thunder Chicken said:
I just saw the picture of the setting of the car. The only thing that jumps out at me is that you may have set the front wheel contact points at the level of the front wheel axles. The rear wheels look like they are set appropriately.
Click to expand...
Now I corrected the values, they were indeed wrong.

It's funny, sometimes it gives infinity and other times it doesn't.
I probably need to initialize more variables in the constructor.
 
One thing to note is that the suspension should keep the vessel level so long as the z-position of the CG in vessel coordinates is anywhere between the z-positions of the front and rear axles. If it is outside of that range you'll get a negative front or rear weight, and subsequently you'll have negative damping values. The car will flip forward or backward in a physically correct manner if this happens.

The code also assumes that the CG is on the centerline of the vessel (x=0). If the CG is not at x=0, then you would need to vary the stiffness of the left and right suspension components as well. My assumption was that this was going to be used for more-or-less conventional symmetric vessels.

If implemented correctly, this code should allow you to put the car on any planetary body, with any positive value of local acceleration of gravity, and the car should sit appropriately with the wheels on the surface.
 
Well, I tested the code on Orbiter Windows to rule out any Linux issues and I can confirm that... my code is broken on cross-platform.

As soon as I apply the accelerator the simulator explodes.
 
Well, I think I fixed it... temporarily. What I did was split the weight by 2 and spread it between the front and rear. It's not a great solution but it allows me to keep going until I have something better.

Thank you all for your help and ideas.
 
Matias Saibene said:
Well, I think I fixed it... temporarily. What I did was split the weight by 2 and spread it between the front and rear. It's not a great solution but it allows me to keep going until I have something better.

Thank you all for your help and ideas.
Click to expand...
I don't know if this is what is happening, but if your mesh is initially loaded such that contact points are well below the surface, when the touchdown points are set in ClbkPostCreation, that can cause an excessively large force on the touchdown point springs which can send the vessel into space instantly. You should try setting the altitude of the car in the scenario such that the tire contacts are pretty close to the surface. That might help.
 
Thunder Chicken said:
I don't know if this is what is happening, but if your mesh is initially loaded such that contact points are well below the surface, when the touchdown points are set in ClbkPostCreation, that can cause an excessively large force on the touchdown point springs which can send the vessel into space instantly. You should try setting the altitude of the car in the scenario such that the tire contacts are pretty close to the surface. That might help.
Click to expand...
I tried that too without positive results.
 
Matias Saibene said:
Click to expand...
Looks good! You may be having steering problems due to the weight distribution on the tires. From your numbers most of the weight is on the rear wheels, and very little weight is on the front wheels used for steering. When you accelerate that will unload the front wheels even more. The front wheels will skid more easily in that situation, which is a correct behavior.

You may want to consider using ShiftMesh to relocate the CG about half-way between the front and rear wheels to put more weight on the front wheels.
 
Thunder Chicken said:
Looks good! You may be having steering problems due to the weight distribution on the tires. From your numbers most of the weight is on the rear wheels, and very little weight is on the front wheels used for steering. When you accelerate that will unload the front wheels even more. The front wheels will skid more easily in that situation, which is a correct behavior.

You may want to consider using ShiftMesh to relocate the CG about half-way between the front and rear wheels to put more weight on the front wheels.
Click to expand...
Thanks, though I haven't actually programmed the rotation keys yet.
I'm programming this like a house of cards carefully adding each function and testing it one by one.
 
Now I have another problem that causes segfaults.
It turns out that when I start to turn (by pressing 1 or 3 on the numeric keypad) Orbiter crashes. Both on Linux and Windows.
I used Cppcheck to fix all my code and initialize some variables that I had forgotten, I also used Valgrind to debug it but Valgrind tells me that it is a ZTreeMgr error (on Linux).
And on Windows the Orbiter log itself tells me that it is a D3D9 problem.
I suspect that it is something with the TouchdownPoints again and that is why I am going to study the GeneralVehicle code from fred18, to see if I can adapt it to mine and fix it. But I also have the doubt:
am I causing problems for D3D9 too?

This is from my Orbiter log:

000163.281: D3D9ERROR: D:\a\orbiter\orbiter\OVP\D3D9Client\Scene.cpp Line:1249 Error:-2005530516 pDevice->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER | D3DCLEAR_STENCIL, 0, 1.0f, 0L)

and I use this code to load the mesh:
C++: 
void UCFO::clbkSetClassCaps(FILEHANDLE cfg){


    //Get vessel parameters from configuration file,
    //and set the physical vessel parameters.

    if(!oapiReadItem_string(cfg, "Mesh", MeshName)){
        TerminateAtError("Mesh", GetName(), "car");
    }

    SetMeshVisibilityMode (AddMesh (mhUCFO = oapiLoadMeshGlobal (MeshName)), MESHVIS_ALWAYS);
}...

Am I doing something wrong?
 

Attachments

Matias Saibene said:
Now I have another problem that causes segfaults.
It turns out that when I start to turn (by pressing 1 or 3 on the numeric keypad) Orbiter crashes. Both on Linux and Windows.
I used Cppcheck to fix all my code and initialize some variables that I had forgotten, I also used Valgrind to debug it but Valgrind tells me that it is a ZTreeMgr error (on Linux).
And on Windows the Orbiter log itself tells me that it is a D3D9 problem.
I suspect that it is something with the TouchdownPoints again and that is why I am going to study the GeneralVehicle code from fred18, to see if I can adapt it to mine and fix it. But I also have the doubt:
am I causing problems for D3D9 too?

This is from my Orbiter log:

000163.281: D3D9ERROR: D:\a\orbiter\orbiter\OVP\D3D9Client\Scene.cpp Line:1249 Error:-2005530516 pDevice->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER | D3DCLEAR_STENCIL, 0, 1.0f, 0L)

and I use this code to load the mesh:
C++: 
void UCFO::clbkSetClassCaps(FILEHANDLE cfg){


    //Get vessel parameters from configuration file,
    //and set the physical vessel parameters.

    if(!oapiReadItem_string(cfg, "Mesh", MeshName)){
        TerminateAtError("Mesh", GetName(), "car");
    }

    SetMeshVisibilityMode (AddMesh (mhUCFO = oapiLoadMeshGlobal (MeshName)), MESHVIS_ALWAYS);
}...

Am I doing something wrong?
Click to expand...
Do you also get this when you hit the throttle or any other key, or just the keypad 1/3 keys?

You might want to temporarily disable the touchdown point definitions and see if you still get the segfault hitting those keys to isolate the problem. You really can't fix the problem until you know for certain where it resides.
 
Thunder Chicken said:
Do you also get this when you hit the throttle or any other key, or just the keypad 1/3 keys?

You might want to temporarily disable the touchdown point definitions and see if you still get the segfault hitting those keys to isolate the problem. You really can't fix the problem until you know for certain where it resides.
Click to expand...
Only when I press the 1/3 keys.
I'll try your suggestion.

EDIT:
Valgrind tells me that the problem is in how I define the animations (correct me if I'm wrong):
Code: 
==35813== 8 bytes in 1 blocks are still reachable in loss record 242 of 48,264
==35813==    at 0x4846613: operator new[](unsigned long) (vg_replace_malloc.c:729)
==35813==    by 0x3676A2: Vessel::AddAnimationComponent(unsigned int, double, double, MGROUP_TRANSFORM*, ANIMATIONCOMP*) (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x370060: VESSEL::AddAnimationComponent(unsigned int, double, double, MGROUP_TRANSFORM*, void*) const (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x1633BEDD: UCFO::DefineAnimations() (main.cpp:407)
==35813==    by 0x1633D5B7: UCFO::clbkSetClassCaps(void*) (main.cpp:711)
==35813==    by 0x346AC3: Vessel::SetClassCaps(std::basic_ifstream<char, std::char_traits<char> >&) (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x346377: Vessel::Vessel(PlanetarySystem const*, char const*, char const*, std::basic_ifstream<char, std::char_traits<char> >&) (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x2ED94B: PlanetarySystem::InitState(char const*) (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x2D8625: Orbiter::StartSession(Config*, char const*) (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x2D830B: Orbiter::Launch(char const*) (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x302B22: DlgLaunchpad::DrawScenarios() (in /home/matias/orbiter_test/Orbiter/Orbiter)
==35813==    by 0x3028A4: DlgLaunchpad::Show() (in /home/matias/orbiter_test/Orbiter/Orbiter)

And it refers to these lines:

C++: 
ANIMATIONCOMPONENT_HANDLE flw_parent1 = AddAnimationComponent(anim_left_front_wheel_steer, 0, 1, &left_front_wheel_steer);

    ANIMATIONCOMPONENT_HANDLE flw_parent2 = AddAnimationComponent(anim_left_front_wheel_travel, 0, 1,&left_front_wheel_travel, flw_parent1);

    AddAnimationComponent(anim_left_front_wheel_rotation, 0, 1, &left_front_wheel_rotate, flw_parent2);

In fact, none of the wheel animations work.
 
Last edited:
I'm no valgrind expert, nor a linux developer, but the output of valgrind seems more like telling you that there's a memory-leak (one has constructed an object with "new", but that object is never released - with "delete").
As ther's no delete, valgrind cannot tell you where that is missing - it can only help you by telling what created object is still not released at programm end.

That should of course be fixed, but has most likely nothing to do with the non-working of the animation(s).
 
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