elchtest mod :)

[sebiastisch]

Thanks for your detailed explanation!

The problem is, that the center of mass wheel speed v is actually updated one step after the torque was applied to the wheel?
Is that the reason for the discrepancy between the linear from rotational speed r*w and the linear speed v?

In other words: When accelerating, vdrift calculates the new rotational speed, uses that and the old linear velocity to calculate the slip and then uses this to calculate the new linear forces (and speeds). Thus the resulting forces depend on the timestep, although they shouldn't.
Doesn't raising the wheel inertia change the whole car behavior?
There is no way to calculate that in a closed formula?

Do you plan to simulate the wheels as a rigid body? If you can afford to run bullet at 600-1000Hz in you simulation I would propose to create the whole vehicle/suspension in blender/maya. Export it as .bullet and load it into your bullet world.

We could do this in our simulation, as the computers we are using here, are probably not comparable to the normal vdrift players equipment. But it sounds like a lot of work and I don't see the benefits, as in our research the higher abstraction level (decision making and A.I Stuff) is in the foreground it is a little over the top. Additionally, I think the susppension does not need so high framerates. Just like the chassis does not need as high framerates as the suspension. nevertheless the wheels are already in our bullet world (as dynamic objects without mass). but their state is completely managed by vdrift. what i can already do is check for collision with the world (this is no problem, even with the high update rates, as vdrift runs on something like 1/480s^-1 and bullet uses 1/60 at the moment).
Which means, at the moment the car moves/"rolls" 8 steps in a static bullet world, then the bullet update checks for chassis crashes and sets the bullet world forward. i will upload a video, if i find the time and if you are interested.

i guess i will just set the wheel contacts with the cylinder collision instead of the raycast. this should do the thing for us.

Just an off topic question: Are there different kinds of suspensions modeled in vdrift?

BTW: forget about the inheritance stuff, I was writing about in my last post. The btActionInterface does give enough access (although not very much). You can model the rigid bodys (wheels and chassis) in your special action interface.