VehicleControl handbreak

Troubleshooting physics
1

Hi Guys…
Im having trouble getting my vehicle to stop…
Does anyone know of a good strategy to implement a handbreak or engine break using VehicleControl. When i break i set

accelerate(0);
brake(100);

but if the vehicle has stopped on an incline… It seems wobble down the hill. It looks like the break is applied in pulses. so it looks like a wobble

i have also tried adding these which helped a little… But not enough

    setFrictionSlip(20);
    setFriction(1f);
    setDamping(.75f, .75f);
2

I personally have never worked with the vehicle control, but since this is all connected to physics, you could try to just disable your physics control (RigidBodyControl or so) and maybe it does work.

4

Can you maybe show a video with physics bebug enabled?

5

sure… here you go

it not hugely noticeable but over time… the vehicle drift quite a bit…

I also tried increasing the friction from 1 to 100 . But that didn’t help… I think its between 0-1 anyway

6

Did you try to disable the whole physics control, so that it kind of freezes at the last position?

7

no didnt try that… wouldn’t that have more consequences… like not responding to things running into it. I would have to replace the controller with with a rigid body… Or perhaps insert a rigid body like an anchor or stopper…

8

I am not sure, but maybe it does work if you enable kinematic mode during the time the vehicle stands still.

9

Have you tried setting the friction (as well as the other settings) on the floor as well?

10

I just tried it now. But no effect… Its still slipping down hill…
on the terrain i have

CollisionShape sceneShape = new HeightfieldCollisionShape(terrain.getHeightMap(), new Vector3f(1, 1, 1));
RigidBodyControl landscape = new RigidBodyControl(sceneShape, 0);
landscape.setRestitution(0);
landscape.setLinearDamping(1);
landscape.setFriction(1);
loadModel.addControl(landscape);

and on the vehicle i put

public class BetterVehicleControl extends VehicleControl implements GameCharacterControl{   

public BetterVehicleControl(int mass, GameVehicleNode vehicleNode, VehicleBlenderModel blenderModel, AssetManager assetManager) {
    ...
    setFrictionSlip(20);
    setFriction(1f);
    setDamping(.75f, .75f);
11

In short no, I actually suspect due to some deep diving, that there is a bug in the bullet source, that roughly overestimates the braking force by the Wheelamount. My simple solution was to simply check
a) is brak applied?
b) is speed < x
if so just freeze the vehicle in place by changing mass to 0
→ If required add a collision listener, to unfreeze if something else crashes into.