<!DOCTYPE html
  PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<!--
Copyright (c) 2006 UGS Corp.

All Rights Reserved.

This software and related documentation are proprietary to UGS Corp.
-->
<html>
   <head>
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
      <title>Measurement Preferences</title>
      <script language="javaScript">
        abridged="false";
        displayConditions=new Array();
      </script>
      <link type="text/css" href="../css/main_styles.css" rel="stylesheet">
   </head>
   <body class="bodydocs" onload="top.pageLoader()" bgcolor="#FFFFFF">
      <div class="title_topic3" id="xps10_pagetitle">Measurement Preferences</div>
      <hr noshade="true">
      <p class="para_topic">These preferences are used by certain mass property and <b class="uiTerm">Measure</b> options including:
      </p>
      <ul>
         <li>
            <p class="para_item"><b class="uiTerm">Face Properties</b></p>
         </li>
         <li>
            <p class="para_item"><b class="uiTerm">Mass Properties</b></p>
         </li>
         <li>
            <p class="para_item"><b class="uiTerm">Area using Curves</b></p>
         </li>
      </ul>
      <p class="para_topic">You can specify the following preferences using Preferences&rarr;Measurement:</p>
      <table frame="border" rules="all" align="center">
         <tr>
            <th colspan="1" rowspan="1">
               <p class="para_th">Area Using Curves</p>
            </th>
            <td colspan="1" rowspan="1">
               <p class="para_td">Lets you set a tolerance for the boundary.</p>
            </td>
         </tr>
         <tr>
            <th colspan="1" rowspan="1">
               <p class="para_th">Face Properties</p>
               <p align="center"><img align="bottom" src="graphics/face_properties.gif"></p>
            </th>
            <td colspan="1" rowspan="1">
               <p class="para_td">Accuracy Parameter</p>
               <p class="para_td">The Accuracy Parameter value only applies when a face is non-analytical, such as a b-surface. This value has no effect on calculations for analytical faces (i.e., planes and cylinders).</p>
               <p class="para_td">The value you specify must be between zero and one, for example, 0.99. The nearer the accuracy parameter is to one, the more accurate the analysis will be; however, the speed of the calculation will be reduced.</p>
            </td>
         </tr>
         <tr>
            <th colspan="1" rowspan="1">
               <p class="para_th">Mass Properties</p>
               <p align="center"><img align="bottom" src="graphics/mass_properties.gif"></p>
            </th>
            <td colspan="1" rowspan="1">
               <p class="para_td">Lets you specify <b class="uiTerm">Relative Tolerances</b> or an <b class="uiTerm">Accuracy Parameter</b> for the mass property computations
               </p>
               <p class="para_td">Tolerances, Accuracy and Units</p>
               <p class="para_td">Specify a Relative Tolerance or an Accuracy Parameter for the mass property computations</p>
               <p class="para_td">For simple solids with analytic faces (i.e., planar, cylindrical), the default accuracy value is sufficient. For more complicated solids with B-Surface faces, accuracy values closer to 1.0 may be necessary. The maximum accuracy value used by the system is 0.999999. You might try several values, such as 0.99, 0.999, 0.9999, etc. and see if the results seem to converge. Also, check the relative errors. For a specified accuracy value, the +/- range errors give a conservative estimate of the accuracy achieved.</p>
               <p class="para_td">If Relative Tolerances are specified, the system iterates on the accuracy values 0.9, 0.99, 0.999, 0.9999, 0.99999, and 0.999999, until successive mass property values are within the specified relative tolerances.</p>
               <p class="para_td">The relative tolerance values are defined by</p>
               <p align="center"><img align="bottom" src="graphics/ana_infoat48.gif"></p>
               <p class="para_td">The test value (or estimated relative tolerance) is</p>
               <p align="center"><img align="bottom" src="graphics/ana_infoat47.gif"></p>
               <p class="para_td">where MP(n) is the mass property value for the n-th iteration on the accuracy value.</p>
               <p class="para_td">If a percent relative tolerance of 0.0 is specified, no testing is done for the corresponding mass property value, although all the mass property values are computed using the same accuracy values.</p>
            </td>
         </tr>
      </table><br></body>
</html>