Topology Optimization 2D: Growing a Cantilever Bracket

This simulator runs a real bi-directional evolutionary structural optimization (BESO) loop on a 2D spring lattice. A dense planar "ground structure" of nodes and springs — every neighbor within one grid cell connected by a Hookean spring — is loaded and relaxed each frame via damped explicit dynamics until it settles into its equilibrium deformation. Periodically the optimizer measures how much strain energy each cell's springs are carrying, ranks every cell by that sensitivity, and keeps only the top fraction solid, iteratively converging on the material layout that survives with the least mass for the most stiffness — the same generative-design principle used to grow real 3D-printed aircraft brackets, worked here in the classic 2D plane-stress domain (MBB-beam style) that the BESO/SIMP literature itself is built on.