A visualization module of an imaging system having a 3D geocellular model generated for illustrating rock types within a subterranean formation. The visualization module can determine that cells of the 3D geocellular model are visible to a field of view for a viewing user. For each cell determined to be visible, the visualization module can determine a rock type for the cell and that one or more faces of the cell are visible. For each face determined to be visible, the visualization module can determine an orientation of the face; determine that an image corresponds to the determined orientation and determined rock type; and apply the image to the face of the cell in the 3D geocellular model.