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      <title>Mass Properties</title>
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      <div class="title_topic1" id="xps10_pagetitle">Mass Properties</div>
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      <p class="para_topic">To access the Mass Properties toolbar, select Analysis&rarr;Mass Properties.  </p>
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      <div class="title_figure">Toolbar for Mass Properties</div>
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               <p class="para_td"><b class="uiTerm">Keep Measure</b>  
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               <p class="para_td">When you press this button, NX creates a measurement feature.  The measurement feature contains expressions for the Volume, Mass, Surface Area and Center of Gyration of the selected bodies.  The centroid point is an associative point for the center of mass for the selected bodies. Therefore, as you make changes, the object updates for you to view the change.  </p>
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               <p class="para_td"><b class="uiTerm">Display Annotation</b></p>
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               <p class="para_td">When you press this button an annotation is created containing the mass property values for the selected objects.  If you select multiple objects the value is the combined value. </p>
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               <p class="para_td"><b class="uiTerm">Create Principal Axes</b>  
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               <p class="para_td">This button is shared under the option toggle with <b class="uiTerm">Display Annotation</b>.  When active this button enables the creation of a coordinate system aligned with the principal axes of the selected bodies as you select each body.  This coordinate system is located at the centroid, but it is not associative. 
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               <p class="para_td"><b class="uiTerm">Information</b></p>
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               <p class="para_td">Displays the calculated data for all of the Mass Properties options previously discussed in the Information window.</p>
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               <p class="para_td"><b class="uiTerm">Cancel</b></p>
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               <p class="para_td">Ends the measurement function.</p>
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      </table><br><p class="para_topic">If you simply want to measure Volume, Mass, etc., then the system uses a default accuracy value and the Units are the CAE units set in Analysis -&rarr; Units -&rarr; Unit Manager.  It is only if you select Info that the system uses accuracy values or relative tolerance values.  These values are defined in Preferences -&rarr; Measurement.  Also, if you select Info, the units are those defined in Analysis -&rarr; Units.</p>
      <p class="para_topic">Data displayed in the Information window is converted to the current units. If you change the unit settings using Analysis&rarr;Units, information will be displayed in the new units.</p>
      <div class="title_division">Selecting the Solid Bodies</div>
      <p class="para_division">Three-dimensional solid body analysis is only allowed for solid bodies. Faces or other non-solid bodies are disallowed.</p>
      <p class="para_division">After you select all of the solid bodies you want to analyze, the system computes the mass properties, and computes additional properties from these.</p>
      <p class="para_division">Selecting multiple solid bodies causes the system to generate a single total for all of the selected solid bodies for each calculation.</p>
      <div class="title_division">Reading the Data</div>
      <p class="para_division">After the system analyzes the selected bodies, the on-screen feedback displays the analysis data.  An option menu allows you to view the display of either the Volume, Surface Area, Mass or Radius of Gyration.  View additional mass properties in the information window by pressing the Information button.</p>
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               <p class="para_td">Area/Volume/Mass</p>
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               <p class="para_td">Obtains the total face area, volume and mass of a 3D object.</p>
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               <p class="para_td">Centroid/1st Mom</p>
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               <p class="para_td">Obtains the center of mass, or Centroid.</p>
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               <p class="para_td">Moments of Inertia</p>
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               <p class="para_td">Obtains the moment of inertia for certain 3D objects of uniform density about specified axes.</p>
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               <p class="para_td">Products of Inertia</p>
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               <p class="para_td">The Products of Inertia, along with the Moments of Inertia, form the inertia tensor, and are important in rotational dynamics.</p>
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               <p class="para_td">Principal Axes/Moments</p>
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               <p class="para_td">The Principal Axes/Moments is an orthogonal system of three axes through the center of mass such that the three products of inertia relative to the system are all zero.</p>
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               <p class="para_td">Radius of Gyration</p>
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               <p class="para_td">Calculates the radius of gyration.</p>
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               <p class="para_td">Information</p>
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               <p class="para_td">Displays the calculated data for all of the Mass Properties options previously discussed in the Information window.</p>
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               <p class="para_td">Relative Errors</p>
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               <p class="para_td">Are estimates of the relative tolerances achieved in calculating the mass properties. Often the relative errors are less than the specified relative tolerances, indicating that the mass property values are correct to within tighter tolerances than those specified.</p>
               <p class="para_td">If only a single accuracy value is specified, then +/- Range Errors are given. </p>
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