Four routes to a better surface, each suited to a different situation
Leaving a print as-printed, sanding and filling it by hand, applying a chemical or vapor coating, or redesigning the geometry to make finishing easier are four genuinely different strategies for the same underlying goal: getting from visible layer lines to whatever finish you actually need. None of them is universally right; the correct one depends on how far from as-printed your target is, how complex the geometry is, and how much labor you are willing to spend.
How the selection works
If as-printed is genuinely fine, that ends the decision. Otherwise, complex or detailed geometry with low labor tolerance points toward redesigning to simplify the areas that need the best finish, since hand-finishing detailed geometry is disproportionately slow. A glossy or painted target generally needs sanding and filling as groundwork regardless of labor tolerance; a smooth matte target with high labor tolerance favors thorough sanding, while lower tolerance favors a faster coating-based route.
Worked example
A smooth matte target, simple geometry, medium labor tolerance: the tool recommends a coating or vapor treatment as the faster path to a smooth matte finish on simple geometry, with progressive sanding and filling shown as the alternative if you would rather have full manual control over the result.
A common mistake
A frequent error is choosing a finishing route based purely on the target look while ignoring how much labor tolerance you actually have for the project timeline. A show-quality finish on a complex part sounds appealing but can take far longer in practice than expected; be honest about your real available time before committing to the most labor-intensive route.
Limitations
This compares finishing routes qualitatively by appearance target, geometry, and labor; it does not know your specific material's chemical or thermal compatibility with a given coating or vapor treatment. Test on a scrap piece before treating a finished part.