Physx Vehicle wheels radius

Gaming and Visualization Technologies APIs Physics Modeling (closed)
1

Hello.
I have configured vehicle, and it drives!
It is 4WD and 4 wheels.

But, with wheels radius above 0.5(0.6) of real diameter of wheel.
Code:

WheelRadiuses[i] = std::max(WheelAABBs[i].GetSize().y, WheelAABBs[i].GetSize().z) * 0.975f * 1.0f;

GetSize returns 2.0f * Extents_of_AABB(from center to max).
In this configuration, vehicle drives normally. With suspension travel and etc.

But. In this code(that describes REAL wheel radius):

WheelRadiuses[i] = std::max(WheelAABBs[i].GetSize().y, WheelAABBs[i].GetSize().z) * 0.975f * 0.5f;

Vehicle not drives!
Wheels spinning, but vehicle body is freezed.

Screenshot from PVD(real wheel radius):
https://yadi.sk/d/-G3z0NCfcTwwc
And from app:
https://yadi.sk/d/7-1HrSm9cTx26

I found another problem:
after some vehicle moving, I stop vehicle.
And after stopping, vehicle’s body goes up.
next, when I start driving, body goes down.

P.S. body not collides with ground.

2

So you reduce the wheels radius by half and the car doesn’t move, right? Any chance that the body of the car is resting on the ground?

3

Yes.

Look at screenshots.
There are no any intersections of the body and the ground.

4

MikePhysX, help me.
I don’t understand problem!!

This problem(more important, than wheel radius):
after some vehicle moving, I stop vehicle.
And after stopping, vehicle’s body goes up.
next, when I start driving, body goes down.

5

Could you please provide a PVD capture? I don’t know what the problem is just by looking at the screenshots.

6

Ok, it’s here:
https://yadi.sk/d/VWBXvt8dcaqRD

  • problem: unstable drive in a straight line(steering = 0).
    tends to the left-right

  • dependence vehicle physics by size of vehicle and world.
    on scale = 1, vehicle very nimble and quick, suspension works at full travel, not kept road(not straight line driving, with steering = 0).
    on scale = 2, vehicle very heavy, and the suspension does not work, and very well-kept road!

7

I’m not sure what is going on with your vehicle exactly, but why do you have 65 scenes, and more importantly, why does the vehicle have 1430 shapes on it???
External Media

8

MikePhysX, why it can occurs?

m_pScene = m_pPhysicsSDK->createScene(SceneDesc);

calls one time!

vehicle have 38 shapes.
I trace in debug app, step-by-step, create scene calls once.

wtf?

9

And you aren’t looping on it?

10

Yes!
only one time initialization.

11

I don’t understand either. I have never seen anything quite like that PVD capture. It doesn’t make sense to me. I would need a repro application to make more progress with it.

–Mike