Units

Here some reading about units:
 * SI system
 * Imperial units
 * SI derived units
 * angle units

Examples
tu = App.Units.translateUnit tu('10 m') tu('3/8 in') tu('100 km/h') tu('100 km/h')/tu('m/s') tu('m^2*kg*s^-3*A^-2') # or tu('(m^2*kg)/(A^2*s^3)') tu('2*pi rad') # full circle tu('2*pi rad') / tu('gon') tu('1fo+(3+7/16)in') tu('1\'+(3+7/16)"') # the ' we have to escape because of python tu('sin(pi)') b = Part.makeBox(tu('2in'),tu('2m')/100,10)
 * 1) -- some examples of the FreeCAD unit translation system --
 * 2) make a shortcut for the examples
 * 1) 10 meters in internal numbers
 * 1) doing math
 * 1) combined stuff
 * 1) transfer to other units
 * 1) derived units (Ohm)
 * 1) angles
 * 1) as gon
 * 1) more imperial
 * 1) or
 * 1) trigonometry
 * 1) Using translated units as parameters, this command will create a 50.8mm x 20mm x 10mm box

Supported units
Here the defined units in FreeCAD so far. It's easy to add an own one. The definition is here.

Metric length "mm"   1.0;        // millimeter       (internal standard length) "m"    1000.0;     // meter "cm"   10.0;       // centimeter "dm"   100.0;      // decimeter "km"   1000000.0;  // kilometer Imperial lenth "in" "\"" 25.4;       // inch "fo" "'"   304.8;      // foot "th"       0.0254;     // thou "yr"       914.4;      // yard Metric mass "kg"    1.0;        // kilogram       (internal standard mass) "g"     0.001;      // gram "mg"    0.000001;   // milligram "t"     1000.0;     // ton Imperial mass "lb"    0.45359237; // pound "oz"    0.45359237; // ounce "st"    6.35029318; // Stone "cwt"   50.80234544;// hundredweights Angle "deg"   1.0;        // degree         (internal standard angle) "rad"   180/M_PI;   // radian          "gon"   360.0/400.0;// gon         Time "s"     1.0;        // second         (internal standard time) "min"   60.0;       // minute "h"     3600.0;     // hour  Rest of SI "A"     1.0;        // Ampere         (internal standard electric current) "K"     1.0;        // Kelvin         (internal standard thermodynamic temperature) "cd"    1.0;        // Candela        (internal standard luminous intensity) "mol"  1.0;        // Mole           (internal standard amount of substance) Metric Volume "yl"   1.0;        // microliter mm^3(derived  standard volume) "ml"   1000.0;     // milliliter cm^3 "l"    1000000.0;  // Liter      dm^3