Thanks a lot for your reply. Unfortunately, I couldn't find anything helpful in the documentation.
Let me explain in more detail.
In abstract terms, I need an object that can can represent a vector field, with the appropriate API allowing to obtain vector values at any point (or set of points) in space.
In practical terms, I need to get the force exerted by, e.g. a Wind object, on a particle at a given world position. This is the wind force that a C4D particle at that position would "feel" when simulated. Is there a public API to get that force? I stress again that the force is normally position-dependent, hence the "parameters" of the Wind are not what I'm looking for. For some force fields (e.g. drag), the force depends on the velocity (again, that of each specific particle); for others (such as gravity) the force would be constant.
The only thing I could find in the documentation that resembles what I am looking for are the functions for sampling a field:
FieldObject::Sample() and related. These functions allow getting field values at a set of points in space, which is exactly what I need. However, C4D fields seem to be geometric objects, not directly related to dynamics, and seem designed to represent falloffs rather than vector fields. I will end up using C4D fields if there's nothing else available, but I'd rather let clients use the appropriate C4D tools for particle dynamics. On the other hand, maybe I'm wrong about C4D fields - can they be used to directly influence particle motion?