Jpct unit setup

[nima.sh23]

Is there a way to setup world units?
for example change length unit to millimeter.

[EgonOlsen]

No, and wouldn't be any point in doing so. The scene's scale solely depends on your setup. You can define one unit as one meter or 10 or 100...it doesn't matter as long as you adjust everything else (like camera position and movement speed) accordingly and as long as you stay within a reasonable range for not running into floating point accuracy issues.