Units
Geometry is always in millimeters, and everything else takes whatever common unit you write.
Geometry
Files are read in millimeters, including STL, which carries no units at all. A part drawn in
inches needs --scale 25.4 and one in meters needs --scale 1000. If the bounding box in
wobbl inspect looks 25.4 or 1000 times off, that is the cause, and a part under 1 mm or over
20 m across gets a note saying so. Points in loads and selectors, like at 0,-30,66 or
within 15 of 50,-25,35, are in millimeters too.
Loads and stresses
| Quantity | Units |
|---|---|
| force | N, kN, mN, lbf (also lb, lbs, pound), kip, kgf (also kg), gf |
| pressure and stress | Pa, kPa, MPa, GPa, N/mm2, psi, ksi, bar, mbar, atm, psf |
| moment | N*mm, N*m (also Nm, N.m, N-m), kN*m, in-lb (also lbf*in), ft-lb (also lbf*ft), oz-in |
| acceleration | g, m/s2, mm/s2, ft/s2 |
When any load uses an imperial unit, the results print stresses in psi or ksi and lengths in inches, with the metric values in parentheses next to them.
Heat
Power takes W, mW or kW, films take W/m2K (also written W/(m2K) or W/m2/K), and
durations take s, min or h. Temperatures take C, K or F, and a bare number is
read as Celsius.
Circuits
Circuit values stay in plain SI and accept SPICE style suffixes, so 10k is 10 kilohm,
4k7 is 4.7 kilohm, 22u is 22 microfarads and 2.2meg is 2.2 megohm. Units written after
the number, like 5V, 10uH or 500kHz, are fine too.
What Wobbl uses inside
Every quantity is converted once, on the way in, to one consistent system of millimeters,
newtons, MPa, tonnes, seconds, milliwatts and degrees Celsius, so the solvers never see mixed
units. The results files keep that system and name the unit in each key, as in
governing_MPa and max_disp_mm.