The printing technology changes what the model needs to be.
FDM (filament)
Melted plastic extruded layer by layer.
- Strengths: cheap, large build volumes, wide material range, robust parts.
- Weaknesses: visible layer lines, limited fine detail, weaker along the layer axis.
- Model implications: avoid very fine detail, mind wall thickness relative to nozzle size, and consider that the part is anisotropic — it breaks along layers.
Resin (SLA/DLP/MSLA)
Liquid resin cured by light, layer by layer.
- Strengths: very fine detail, smooth surfaces, excellent for miniatures and jewellery patterns.
- Weaknesses: smaller build volumes, messy post-processing, more brittle, resin needs careful handling.
- Model implications: hollowing with drain holes, supports on non-visible surfaces, and detail can be much finer than FDM allows.
Powder (SLS/MJF)
A laser or binder fuses powder, with unfused powder supporting the part.
- Strengths: no supports needed, complex interlocking geometry possible, strong isotropic parts.
- Weaknesses: industrial cost, grainy surface finish, limited material choice.
- Model implications: interlocking and enclosed geometry becomes viable, but trapped powder needs escape routes just as trapped resin does.
Choosing
- Prototype or functional part: FDM.
- Fine detail, small object: resin.
- Complex geometry, production quantities, strength: powder.
Where generated models are a reasonable fit
Decorative and display objects, where approximate geometry is acceptable and the appeal is the shape rather than the specification. Figurines, ornaments, terrain pieces, props.
Where they are not
Anything mechanical, anything that must fit something else, anything with a tolerance. Generation approximates, and a part that must mate with another part cannot be approximate — that is a CAD job.