Hi- The units in MECHANICA without Pro/ENGINEER (aka Independent Mode, or Standalone Mode) are dictated by the materials you're assigning in the model. You'll notice that the list of materials is presented such as: "BRASS_mmNS", "BRASS_IPS", etc. For example, "BRASS_mmNS" simply states that BRASS has density, Young's Modulus, etc, specified in [mm-N-sec] system of units. Now:- When you create the geometry, you sketch items thinking in "units". A curve between 2 points separated 5 "units" is 5 inches if the material is "BRASS_IPS" and 5 mm when assigning "BRASS_mmNS", aso. Obviously -if you have multiple volumes/shells/etc in the model- you'd have to maintain consistency when defining the materials. I hope this answers your question. RR.