Systems, methods, and computer readable media embodying such methods provide for allowing specification of per-ray clipping information that defines a sub-portion of a 3-D scene in which the ray should be traced. The clipping information can be specified as a clip distance from a ray origin, as an end value of a parametric ray definition, or alternatively the clipping information can be built into a definition of the ray to be traced. The clipping information can be used to check whether portions of an acceleration structure need to be traversed, as well as whether primitives should be tested for intersection. Other aspects include specifying a default object that can be returned as intersected when no primitive was intersected within the sub-portion defined for testing. Further aspects include allowing provision of flags interpretable by an intersection testing resource that control what the intersection testing resource does, and/or what information it reports after conclusion of testing of a ray.