An algorithm to provide haptic feedback directly from volumetric datasets is introduced in this paper. The algorithm is able to reproduce and extend the functionality of surface-based haptics rendering methods. It can be easily implemented on top of existing haptic libraries, such as Sensable's OpenHaptics. In addition, our approach overcomes poor performance in OpenHaptics for models consisting of a large number of polygons (1Million+). The algorithm allows detecting collisions with multiple 3-dimensional shapes. After comparing alternative approaches, such as Depth Buffer and Feedback Buffer, as well as SenseGraphics' Volume Haptics ToolKit (ScalarSurfaceFriction mode), our algorithm delivers the highest performance in terms of rendering time.