FEniTop vs FreeTO

FEniTop is free, open-source software for topology optimization based on FEniCSx. It handles two- and three-dimensional problems on structured or unstructured meshes, with varied element geometries, types, orders, and quadrature degrees. Users express partial differential equations in weak form, while automatic differentiation supports finite-element and sensitivity analysis. PETSc through petsc4py provides linear and nonlinear solvers and preconditioners. Parallel implementations of Optimality Criteria and Method of Moving Asymptotes update design variables. A Helmholtz-type PDE filter targets large-scale parallel problems, including large filter radii. FEniTop can run from laptops to distributed computing clusters. Optimized designs export as XDMF files for ParaView post-processing. Repository examples cover beams in 2D and 3D, a 2D disk, a 3D shell, and a 2D compliant mechanism. The software is licensed under GPL-3.0. Setup instructions specify FEniCSx 0.7.3, PyVista, and Xvfb; Windows 11 instructions use Ubuntu under WSL and Docker Desktop.

FreeTO is free, open-source MATLAB software for initializing, optimizing, and post-processing free-form 3D topology optimization problems. It accepts STL files for a design domain and load-carrying subdomains, together with mesh controls and a target volume fraction. A structured hexahedral mesh is used, and optimized structures have smooth boundaries. Inputs can define supports, force magnitudes, up to nine additional load cases, and regions that must remain unchanged. SIMP is the documented default optimization method, and SEMDOT is also supported. Topologies can be mirrored across up to three specified symmetry planes. Results include compliance, volume fraction, density arrays, element counts, optimization histories, visual topology displays, and an optional STL file. Sample problems cover a GE bracket, airplane bracket, human hand model, and quadcopter. The repository uses an MIT license and other open-source codes. Its available optimizer is optimality criteria; the MMA implementation is commented out, with code available by email request.