Hi there,
Thinking about this, I would like to offer an alternative. My intention is not to have a game like option to play with a car in C4D, but to get closer to a comfortable set up for an animation that results in a car/tire movement. Lets start with a single tire. (All of that is a suggestion/brainstorming)
First we need a path, a “Spline” with a vertices/point on each frame. This can be taken from any baked animation of Character>Manager>Cappucino. In the Timeline (keyframe) the function is called Position Track to Spline. Have at typical “head and tail” of 10 or 20 frames padded to your animation, I will explain later.
If that is a flat Spline with no altitude change, you might project a copy to the surface. Mesh>Spline>Project. With that we have two splines, one above the surface, and which can (if needed) work as “rail”, to get things stable.
I repeat the idea with the axis and the null: Use a child null to pull it to the tire size, which gives two objects and with that the radius.
With the splines we have a representation of the path, and the information of the next position and all other position as well. This allows now to calculate the the distance between Spline vertices, and even the direction. The spline allows as well with the Mesh>Transform Tools>Magnet to manipulate the Spline (preferably a copy), take a large radius if the tire jumps for example.
The points or vertices allows as well to calculate an average position, which could be used for the shock-absorbers and springs to get some “delay” kind of data, as these elements sits between the car body and the tire. With that average, we getting closer to the brainstorming of a whole vehicle.
The rear tires follow the front tires, the front tires follow the next vertices. The frame work of the vehicle follows the average motion based on inertia. based on the numbers of tires, two, three or four. We have to decide how to manage the movement of the vehicle. With two it is rather simple, but it needs an idea to get the tilt movement established in the curves. Having driven a motorcycle bike, the last one a self-build replica of an “EGLI” bol d or, I know how to get the bike into a curve, after 70K miles this is muscle-memory, but it is always lead by an little counter curve. Anyway, that is maybe not really visible.
For a car, I would think of the rear axis as one point (position Mix in XPresso) and the two front tires/axis as two more points. With that we have three points to stabilize the framework of the vehicle. Position, Target and Up vector will create a stabile triangle. The position of each should be an average of the positions—how many—is based on the “set up of the car. A sports-car has maybe half of a second, a family station wagon up to two seconds. Which would be an easy thing in Python (loops) but not impossible in XPresso, but way more work.
I hope that little brainstorming helps to create you very own car set up. Some “Euler Angle” problems will occur if the tire stops, but perhaps a “If” question about equal position of target and tire might heal that. ;o)
There are other methods, with several Null Objects, overcoming some problems. It is all in the preparation, and as I mentioned initially, the target for me is a rendering, not simulating a game interactivity. For game like things, perhaps Dynamic and Python is the key, with key board directing.
Enjoy your weekend