View polyhedra and 4D polytopes. Hundreds provided (Platonic, Archimedean, Kepler-Poinsot & all other uniform polyhedra, Johnson Solids, Stewart toroids, compounds, geodesics etc), plus all 1849 uniform 4D polytopes (the only place all these can be seen). Rotate in 3D, print nets to make your own paper polyhedron models. Put photos on faces. Create new polyhedra: stellation, faceting, zonohedra, dual-morphing, augmentation. Watch 3D cross-sections of 4D polychora morphing as the slicing hyperplane cuts deeper through the polytope. See 4D polytopes projected into 3D, rotate them in 4D, and see their 3D nets. Export to 3D formats. See it all in true 3D if you have red-blue glasses. Stella4D was built on the much-admired Great Stella, now adding the four-dimension to the equation!