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      <title>Check Criteria for Faces (Surfaces) Overview</title>
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      <div class="title_topic4" id="xps10_pagetitle">Check Criteria for Faces (Surfaces) Overview</div>
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               <p class="para_td"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda_checker.html');return(false);">Check VDA-4955 Compliance Overview</a></p>
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               <p class="para_td"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda_criteria.html');return(false);">Description of the Check Criteria</a></p>
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               <p class="para_td">Faces (Surfaces)</p>
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      </table><br><p class="para_topic">The following types of checks are made for faces (surfaces):</p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf1.html');return(false);">Tiny Surface (M1)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf2.html');return(false);">Tiny Patch (M1pa/M1pr)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf3.html');return(false);">Identical Surface (M2)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf4.html');return(false);">Maximum Polynomial Degree (M4)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf5.html');return(false);">Waviness, Ripple (M5)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf6.html');return(false);">Multiple Knots (M6)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf7.html');return(false);">Degenerate Boundary (SU8)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf8.html');return(false);">Minimum Curvature Radius (SU9)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf10.html');return(false);">Corner Angle (SU10)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf11.html');return(false);">Normal Flapping Angle (SU11)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf12.html');return(false);">Maximum Patch Count (SU12)</a></p>
      <p class="para_topic"> <a class="links" href="javascript:void(0)" onclick="top.openFile('nx_analysis/vda4955_check_crit_surf13.html');return(false);">Unused Patch Row (SU13)</a></p>
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            <td valign="top" align="left"><img align="left" src="../graphics/note.gif" alt="Note" title="Note"></td>
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                  <p class="para_note_body">There are special criteria defined in recommendation VDA 4955 which should check the consistence of surfaces. In NX a VDA 4955 surface is represented by the so called underlying surface which, has natural boundaries (i.e. bounded through &quot;simple&quot; mathematical boundaries) and&nbsp;holds the geometry of the face. This underlying surface has to be checked completely (i.e., in its full extent). This way, violations outside of the active region of the face owning this surface are also found.  </p>
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      <p class="para_topic">Offset faces need special treatment. They do not own a surface but point to the geometry of their parent face, which are checked. This is important because in case of exporting offset faces to other CAD-Systems, they may become standalone faces with their own geometry.</p>
      <p class="para_topic">Checks restricted to Non Uniform Rational B-Spline (NURBS) surfaces&nbsp;are carried out for underlying bspline surfaces only.</p>
      <p class="para_topic"> <img align="bottom" src="graphics/v2ugface.gif" border="0">      
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               <p class="para_td">Example of a Face with Underlying NURBS Surface</p>
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               <p class="para_td">1</p>
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               <p class="para_td">Patch</p>
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               <p class="para_td">2</p>
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               <p class="para_td">Edge Curve</p>
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               <p class="para_td">3</p>
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               <p class="para_td">Face</p>
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               <p class="para_td">4</p>
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               <p class="para_td">Surface by n*m Patches</p>
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               <p class="para_td">5</p>
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               <p class="para_td">Patch Boundary</p>
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               <p class="para_td">6</p>
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               <p class="para_td">Edge Loop</p>
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               <p class="para_td">7</p>
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               <p class="para_td">Natural Surface Boundary</p>
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