if I select let say meter in scene panel
and check values in N panel for some object
meters values seems ok
but if I change to cm then it does not show the right values
so would it be a bug or forget some other parameters ?
thanks
happy bl
Not a bug, default behavior, 1 BU is still 1 (no matter what unit you set it to)
Note: Observe Unit Scale, 3Dview (also N-tab: transform dimensions) & play with Unit Presets or Unit Scale… it scales the relation to cosmos thus your object seemingly changes in size, but “there’s no spoon.” 
Had read very nice explanation as to why such behavior but i forgot the source.
if you go from metric to imperial it does change values in N panel dim
but not if you change preset value to cm
and if I have cm instead first preset and add a plane it will be 2 cm
and same dim for the plane unless this changes the scale !
not certain why !
then why do you have these presets defined ?
thanks
happy bl
looks like when you change the unit preset it also changes the unit scale automatically
don’t have to calculate the scale for it!
easier and faster I guess
but hard to see in viewport
thanks
happy bl
why in 3D editor N-panel is always on & Transform > Dimension Tab expanded (wish it could be a floating panel)
if you prefer you can also set @ Units to show Separate Units (check)
eg
try same thing with some presets and look in N panel values
and not so simple then
preset is equivalent to change the scale
but when you add new primitive like planet it does not change size in viewport
so difficult to see you are working with a scale
I read thread on bl site and there are many flaws in that system
and would have to be totally re design to make it more user friendly !
may be in 2.8 I hope so
thanks
happy bl