Use the Part Analysis feature to measure the physical properties of parts and assemblies.  You can measure the surface area, volume, center of gravity, and moments of inertia (including principal values) of a part or assembly.   Area Moments of Inertia and Surface area will be computed when an analysis is performed on a planar surface .

To Analyze An Assembly Or Part:

1. Select the desired assembly or part at the appropriate editing level and then select Analysis from the Tools menu or from the .  The Analysis dialog box appears.
2. Specify the desired level of accuracy for the measurements by entering a value in the Requested accuracy field.  For example, if you want accuracy to within 0.1% (99.9% accuracy), type 0.1.  The default value is 0.001.  Depending on the complexity of your part, it might take a while to measure at higher levels of accuracy.  If approximate values are acceptable, you can trade a lower level of accuracy for faster computation.
3. Specify the mass density of the assembly (mass per unit volume in the current units) or specify the use of the individual part density.  The default assembly density is 1.0.  If you don’t wish to set a mass density for the entire assembly, check the box beside the Use individual part density option.
4. Select Compute to calculate the measurements shown in the properties sheet.  Measurements for the assembly, planar surface, or part’s volume, mass, and center of gravity along each axis appear in their respective fields.  In the Achieved Accuracy field, the estimated degree of accuracy it attained is displayed for the measurements.

Numerical methods are used to obtain the physical properties.  For complex assemblies, planar surfaces or parts, you may not always be able to achieve the specified accuracy.

The other two tabs in the Analysis properties, Surface and Moments of Inertia, work in the same manner.  For example, select the Surface tab and then select Compute to view the total surface area of the assembly or part. On the Moments of Inertia tab, the following options are available:

• Required accuracy (%).  In this field, enter the value to be used for the accuracy percentage of the measurements.  For example, if you want accuracy to within 0.1% (99.9% accuracy), type 0.1.  The default value is 0.001.
• Coordinate System.
• World Coordinate System.  Compute the analysis from the world origin.
• Selected Shape Local Coordinate System.  Compute the analysis from the local origin of the selected shape (Anchor location).
• Compute.  Select this option to calculate the moments of inertia.
• Achieved accuracy (%).  This read-only field displays the estimated degree of accuracy attained.
• (l_xx, l_yy, l_zz).  These read-only fields display the Moments of Inertia of the selected Part/Assembly calculated for the reference axes at the Center of Gravity.  (See diagram below for frame of reference.)
• (l_xy, l_yz, l_zx).  These read-only fields display the Products of Inertia of the selected Part/Assembly calculated for the reference axes at the Center of Gravity.  (See diagram below for frame of reference.)

The remaining read-only fields on this dialog box display the values for Principal Moments and the direction cosines of the Principal Axes.