Moulding is frequently underrated compared to fancier fabrication techniques. It won't get you from mesh to matter in a single bound; but (if you already have one of something) it'll give any 3d-scan then 3d print/CNC machine/laser cut/whatever scheme a good run for its money.
(edit: one that that would be pretty cool, fairly well suited to laser cutters, and hard to duplicate with pure moulding, would be automated application of procedurally generated uniqueness to parts. With a laser cutter, you pay more for greater power and for more time, so making very shallow 'score marks', say to emulate the texture of brick joints, or cracks, or blaster-pockmarks, is cheaper than using a laser as a general-purpose freeform cutting tool. With a bit of software cleverness and a knowledge of the shapes you will be inscribing, it seems like it should be doable to generate 'brickwork' or 'fractures in crumbling masonry' or similar things that shouldn't be identical across your gameworld. You could still use the cheap bulk of moulded plaster or the like; but get the benefit of global uniqueness for surfaces that should have individual character, and not look like they were stamped out of a mould...)