How to control the wheel velocity in btRaycastVehicle?

[mostfool]

I'm new to bullet, and I want to build a car with btRaycastVehicle, I need to add a motor to the wheel to control the rotation velocity of the wheel. But I can't find any function or method can do this.
Is anybody ever faced the same problem? how to sovle ?
Thank you!

[Erwin Coumans]

You are using the raycast vehicle, which doesn't have actual wheels but ray casts instead, so there is no such method.

If you need more accurate vehicles, you can build the wheels using rigid body cylinders and hinge constraints. Open Dynamics Engine has a special wheel constraint, that can help. It would be easy to port this to Bullet if you need it.

Hope this helps,
Erwin