The car demo seems to work by adding force, but In my simulation, I would like to set the wheel speed directly, so the change might be more drastic...

I have created a car with four wheels. Two were JointHinge2 type(for motor), two were JointBall(for support only).

I will set the velocity of two JointHinge2 wheels directly to control the car. What's more, I would like the velocity immediately changed to the value I set, so I set the dParamFMax to Max of float.

However, When I implement it, the car will bounce when velocity suddenly has a large change. What can I do to avoid this bounce and have a smooth car movement?

The reason is that I would like to simulate an infra-red sensor, which will return the distance data of the nearest object on its radial way.

The infra-red sensor can be used for avoiding obstacle.

The principle is quite like a GeomRay, which can be used to get the distance between its origin and the contact point with another object.

So I would like to use the ODE.dCollide() for it. In fact, the GeomRay is not quite useful for me, what I want to get is the distance which will be returned by the function.

I hope I have explained clearly.  I don't know how to set the parameters for the dCollide() function.

I will be glad to know if there's better method.  

Ode.dCollide(SWIGTYPE_p_dGeomID o1,SWIGTYPE_p_dGeomID o2,int flags,dContactGeom contact,int skip);

How can I determine the 'flags' and 'skip' parameter?
The document said flags is the num of collide data you want to get, but if I want to get all, how to set it?

What' more, the 'skip' is the size of dContactGeom class, how to get its size?

Thanks!

To be more specific, i would like to get the distance from a specific point with a specific direction to its nearest object in the Virtual Environment. It's something like a
ray and the object it shine on.

So I would first try to create a GeomRay object, and then use the dCollide function to get the distance. But I have the problems in using the function as I have mentioned.

Ode.dCollide(SWIGTYPE_p_dGeomID o1,SWIGTYPE_p_dGeomID o2,int flags,dContactGeom contact,int skip);

I would like to use this function to get the distance between the start point of a GeomRay and the Geom it contacts with.

How should I set the parameter flags and skip? I don't know the size of dContactGeom object.  

Thanks!