Proportion is a physical matter, too
A prong has to suit the stone, a clearance has to let elements work together, and the connection between head and shank has to make structural sense. It is possible to create a shape that looks excellent zoomed in yet doesn’t leave the right relationships for production.
Prongs and stones are a key checkpoint
If the prong structure doesn’t suit the size or shape of the stone, the fact that the stone fits into the model is not enough. You have to think about what will happen during setting and the material the setter will need.
Check the junctions between parts as well
Sometimes each part looks fine on its own, but the connection between them is the weak point: head against shank, halo against the prongs, or a pavé area against a plain transition.
Printable does not equal production-ready
A printer can produce a shape even when that shape is not a good choice for jewelry. In the same way, a solid can be mathematically valid and still be wrong for manufacturing.