In this paper we present a dipping layer, gridded cell, ray trace tomographic system built at Memorial University for determining seismic velocity tomograms need for processing reflection and vertical seismic profiles. Based on Java, the JRAY system is portable and the code is open source which allows for modifications for research purposes. Our system design allows for parallel computing of individual shot ray paths and we have developed a natural mapping (domain decomposition) into a multi-processor computer. During the presentation we will illustrate the raytracing aspects of the three dimensional tomographic problem using the Landmark Visualization Laboratory Deep Computing Visualization system in the Earth Sciences Department at Memorial University.