This dissertation provides the theoretical basis and implementation details for a complete and practical real-time voxel-based terrain rendering system. We first present a modified Marching Cubes algorithm designed to eliminate choices arising from ambiguities in the original algorithm and its successors in order to facilitate a faster implementation and to simplify the design of a level-of-detail algorithm. The modified Marching Cubes algorithm is extended to operate on voxel data at multiple resolutions in such a way that triangle meshes produced at all levels of detail correctly match geometrical features. We introduce a robust method for seamlessly joining voxel-based terrain meshes of different levels of detail and establish a transition structure that both simplifies the triangulation problem and eliminates the potential for shading artifacts. Finally, we discuss methods for applying texture maps and advanced shading techniques to voxel-based terrain meshes. These methods are designed to be fast and compatible with the widest possible range of graphics hardware across multiple platforms.