SLaSi can make the full 3D simulations for the 3-dimensional lattice or the 2D ones, where the magnetization dynamics is supposed independent on z coordinate, see Jean-Guy Caputo, Yuri Gaididei, Volodymyr P. Kravchuk, Franz G. Mertens, Denis D. Sheka Effective anisotropy of thin nanomagnets: Beyond the surface-anisotropy approach, Phys. Rev. B 76, 174428 (2007), 10.1103/PhysRevB.76.174428, PDF for details.
The current model is defined via volumeModel variable with possible values 3D (default) or 2D.