For visualization in medical imaging, a hybrid volume (22) and surface (24) renderer (16) uses unified ray tracing. Rather than separately rasterizing the surface (24) and ray tracing the volume (22), a same ray or set of rays is used for both the volume (22) and the surface (24). Various effects may be modeled by determining (34) the intersection of the ray with the surface (24) or surfaces (24) and integrating (36) the volume (22) data in parallel. For medical imaging (38), more complex effects, interactive rendering, and/or real-time rendering may be provided by altering the integration for ray tracing based on the detected intersections.