we want to create intersection lines of a brep with a infinite plane in C++. But we could not find any method or function to do this. Basically we want to do the same as the C# function Intersection.BrepPlane does.
Probably you need to use RhinoIntersectBreps with the Brep and the “plane as Brep”.
To get the plane as Brep:
ON_PlaneSurface * pSrf = RhinoPlaneThroughBox(plane, bbox); // use bbox of the Brep, maybe a bit enlarged
ON_Brep *pPlanarSrf = pSrf->ToBrep();
RhinoIntersectBreps(brep, pPlanarSrf);