Creo Parametric is PTC's core 3d parametric modeling and drafting software, formerly Pro/ENGINEER.
Creo Generative is an optional module within Creo Parametric. Generative lets you design a component (e.g. a bracket with mounting point at each end) and then specify mechanical loads and then limiting conditions like maximum local stress, minimum cross-section, maximum deflection, minimum first resonant frequency. Generative then uses multiple FEA runs to whittle away excess material from your model to minimize part volume/weight. You get some pretty interesting organic shapes that resemble tree roots and branches and so-on, so whether or not you can manufacture those shapes or use them as wise inspiration for something completely different. I assume Generative requires a license to Creo Simulate or another embedded FEA package.