[2.1.17] --map-preview-planet with an unknown planet name silently renders Nauvis
Posted: Thu Aug 27, 2026 11:03 am
What did you do?
Ran the command line map preview generator with a planet name that does not exist.
Vanilla, no mods (base, elevated-rails, quality, recycler, space-age), empty
--mod-directory:
What happened?
Exit code 0, and not one mention of the planet anywhere in the output - no warning, no
error. out.png is written and is byte-for-byte identical to the Nauvis preview generated
from the same settings, so the unknown name silently falls back to the default planet.
What did you expect to happen instead?
An error, or at minimum a warning that the planet does not exist. Silently producing a
plausible-looking preview of a different planet than the one requested is the worst
possible outcome for an automated pipeline.
Does it happen always, once, or sometimes?
Always. Verified on 2.1.17 (build 87315) and 2.1.16, Windows 11.
Extra detail
The same silence applies to a valid-looking list: --map-preview-planet=nauvis,vulcanus is
treated as one unknown planet name and also yields Nauvis. Repeating the option
(--map-preview-planet=nauvis --map-preview-planet=vulcanus) renders only Vulcanus, the
last value, also without any message.
In a tool that renders one preview per planet, a typo - or a planet from a mod that failed
to load - therefore yields a Nauvis image stored under another planet's name, with no way
to detect it except hashing the output against a Nauvis render.
Related suggestion, for context: viewtopic.php?t=135892
Ran the command line map preview generator with a planet name that does not exist.
Vanilla, no mods (base, elevated-rails, quality, recycler, space-age), empty
--mod-directory:
Code: Select all
factorio --generate-map-preview=out.png --map-gen-settings=map-gen-settings.json ^
--map-preview-size=512 --map-preview-planet=totally-bogus-name
Exit code 0, and not one mention of the planet anywhere in the output - no warning, no
error. out.png is written and is byte-for-byte identical to the Nauvis preview generated
from the same settings, so the unknown name silently falls back to the default planet.
What did you expect to happen instead?
An error, or at minimum a warning that the planet does not exist. Silently producing a
plausible-looking preview of a different planet than the one requested is the worst
possible outcome for an automated pipeline.
Does it happen always, once, or sometimes?
Always. Verified on 2.1.17 (build 87315) and 2.1.16, Windows 11.
Extra detail
The same silence applies to a valid-looking list: --map-preview-planet=nauvis,vulcanus is
treated as one unknown planet name and also yields Nauvis. Repeating the option
(--map-preview-planet=nauvis --map-preview-planet=vulcanus) renders only Vulcanus, the
last value, also without any message.
In a tool that renders one preview per planet, a typo - or a planet from a mod that failed
to load - therefore yields a Nauvis image stored under another planet's name, with no way
to detect it except hashing the output against a Nauvis render.
Related suggestion, for context: viewtopic.php?t=135892