We present a modeling technique based on the metaphor of interactively sculpting complex 3D objects from a solid material, such as a block of wood or marble. The 3D model is represented in a 3D raster of voxels where each voxel stores local material property information such as color and texture. Sculpting is done by moving 3D voxel-based tools within the model. The affected regions are indicated directly on the 2D projected image of the 3D model. By reducing the complex operations between the 3D tool volume and the 3D model down to primitive voxel-by-voxel operations, coupled with the utilization of a localized ray casting for image updating, our sculpting tool achieves real-time interaction. Furthermore, volume sampling techniques and volume manipulations are employed to ensure that the process of sculpting does not introduce aliasing into the models.