# Mass Properties Window

Used to control and display mass properties analysis of the length, area, or volume measured with the Measure Length tool, Measure Area tool, or Measure Volume tool.

You can access this dialog from the following:
• Measure Length dialog: select Mass Properties
• Measure Area dialog: select Mass Properties
• Measure Area Volume dialog: select Mass Properties

SettingDescription
Mass Per <Length/Area/Volume> Sets the mass per master unit as follows, depending on which measuring tool is selected:
• Mass Per Length (when Measure Length tool is selected) - the linear density per master unit.
• Mass Per Area (when Measure Area tool is selected) - the area density per square master unit.
• Mass Per Volume (when Measure Volume tool is selected) - the volumetric (mass) density per cubic master unit.

This setting affects both the Mass and Moments of Inertia.

File menu > Save… Open the Save Measurement Values dialog, which is used to save the mass properties analysis in a text file.
Moments and Products of Inertia Clicking the Show mass property button expands the Mass Properties window and shows moments and products of inertia.
• Moments of Inertia - Mass moments of inertia — useful for kinematic analysis, including calculating the force required to rotate a body about an axis.
• Products of Inertia - Mass products of inertia.

For closed, planar elements, the area moments of inertia are obtained by setting Mass Per Area to 1.0. In this case, the area moments are displayed as master units to the fourth power. The area moments are required for analyzing the stress across a beam cross section and other areas of engineering analysis.

Note: The combination of the mass moments and polar moments of inertia are commonly referred to as the inertia tensor.
Note: The combination of moments and products of inertia about a given coordinate system can be used to calculate these values for any coordinate system.
Principal Moments Clicking the Show mass property button expands the Mass Properties window and shows Principal Moments and Principal Directions.
• Principal Moments - The maximum, minimum and an intermediate moment of inertia.
• Principal Directions - The three mutually perpendicular axes extending from the centroid along which the maximum, minimum and an intermediate moment of inertia occur. The products of inertia about these axes is zero.

Radii of Gyration Clicking the Show mass property button expands the Mass Properties window and shows the Radii of Gyration, which are an alternate way to express the Moments of Inertia as distances in working units.