Code instead of drawings
In classical CAD an engineer draws each surface. In computational engineering the engineer writes the logic: how wall thickness follows pressure, where cooling channels run, how the injector feeds the chamber. The software then builds the geometry, often as voxels or signed distance fields, which handle complex internal structures well.
Why it fits 3D printing
Additive manufacturing can build almost any shape, but drawing such shapes by hand is slow. Generated geometry and printing fit together: lattices, branching channels and one-piece assemblies come out of the code and go straight to the printer.
Where AI comes in
Once a design is code, its parameters can be searched automatically. Fast physics models evaluate each variant, and an optimiser keeps the best. The rules encode what engineers know; the search finds combinations they would not have tried.