Fast projection-based ray-casting algorithm for rendering curvilinear volumes

We present an efficient and robust ray-casting algorithm for directly rendering a curvilinear volume of arbitrarily-shaped cells. By projecting cell-faces onto the image plane, we have effectively addressed three critical steps of the ray-casting process, namely finding the entry cell-faces for a ray, traversing along the ray from one cell to another, and reconstructing data values at the ray/cell-face intersections. Our algorithm significantly reduces rendering time, alleviates memory space consumption, and overcomes the conventional limitation requiring cells to be convex. Application of this algorithm to several commonly used curvilinear data sets has produced a favorable performance when compared with recently reported algorithms.