1. A method for performing direct rendering of a multi-volume data, comprising: determining whether a volume of the multi-volume data is one of active and inactive via interaction with a ray for the multi-volume data; recording in triplicate a starting point and an end point of the ray for an eyespace; repeating the determining whether the volume is one of active and inactive via interaction with a ray for the multi-volume data and the recording in triplicate the starting point and the end point of the ray for an eyespace for all volumes of the multi-volume data; providing triples from all volumes to an array; sorting the array to create a sorted triples list array; breaking the ray into a plurality of segments using the sorted triples list array; determining which volumes are active for each of the segments via an active volume list; and sampling each segment of the ray to acquire an accumulated result.