f3d (Format 3 Dimensional) is a simple format for storage of 3D datasets supporting different voxel types (8, 16, 32 bit integers, floats) and different grids (cartesian, regular, rectilinear). It does not support curvilinear and unstructured grids.
The package includes viewer application (f3dview-qt) for exploring the f3d volume files. Application uses Qt4 framework. Files can be viewed by displaying volume aligned slices.