I spent several years at Boeing in the 787 Optimization Center as an analyst and the group's lead engineer. The Center was tasked with removing weight from the airplane using Altair’s OptiStruct FEA Optimization software, among others.
The work done was all proprietary, so I created the simple video below to explain the process. FEA-based structural optimization is capable of optimizing over 1000's of different load cases acting on very-complex parts with many competing requirements...the types of parts that might join an airplane's fuselage to its wheels, for instance ;)
These methods were shown to be 4 times more cost-effective than traditional methods at reducing weight.The video above shows topology optimization on an example part that carries two separate loads. You can watch the software converge on the most efficient arrangement of material necessary to carry all loads on the part.
The next step (not shown) would be to redesign the part in a configuration that is manufacturable, creating stiffening members in the same pattern that the topology results show. A Size and Shape optimization would then be run to determine the necessary beam and flange dimensions to keep stresses under the required maximum. The final result would be the lightest-weight part capable of meeting all specified criteria (strength, stiffness, stability, etc.) for the given loads.