Fabrication
The physical production of an artwork (casting, welding, printing, carving) often carried out by specialized studios working from the artist's designs.
Much of the large-scale public art you've seen was artist-designed but fabricator-built: foundries, metal shops, and fabrication studios translate a concept and a maquette into something that stands up to wind load and winters. That's collaboration, not compromise. Knowing what to hand off is part of the craft.
Two contract questions worth settling early: who absorbs fabrication cost overruns, and who warranties materials and workmanship after installation. Bringing the fabricator into design conversations early is the cheapest insurance available. Buildability problems found on paper cost nothing.