AcGeEntity3d AcGePointEnt3d AcGePointOnCurve3d
class AcGePointOnCurve3d : public AcGePointEnt3d;
geponc3d.h
Represents a point on a 3D parametric curve. This class encapsulates all of the geometric information of a point on a 3D curve including its parameter value, 3D coordinates, and derivatives.
Geometry library documentation in ObjectARX Developer's Guide