<!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>Multibend Bracket tips and techniques</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">Multibend Bracket tips and techniques</div>
      <hr noshade="true">
      <table cellspacing="4" align="center">
         <tr valign="top">
            <td bgcolor="#f7f7f7" colspan="1" rowspan="1">
               <p class="para_td"><a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/smfea_multibend_brack.html');return(false);">Multibend Bracket Overview</a></p>
            </td>
            <td bgcolor="#f7f7f7" colspan="1" rowspan="1">
               <p class="para_td"><a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/multibnd_geo_sel.html');return(false);">Options</a></p>
            </td>
            <td bgcolor="#f7f7f7" colspan="1" rowspan="1">
               <p class="para_td"><a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/build_multi_parts.html');return(false);">Related Topics</a></p>
            </td>
         </tr>
      </table><br><div class="title_division">Editing multibend brackets</div>
      <p class="para_division">Editing a multibend bracket is very similar to creating a multibend bracket. Upon entering the dialog box, you can change bend parameters, add or delete bends, and edit the sketch. Note that the multibend bracket must be in its creation state prior to editing.</p>
      <p class="para_division">If you add a new bend, the model will update when you enter the sketcher.</p>
      <p class="para_division">As with all features, if you delete faces and edges (due to deleting a bend or editing the sketch) downstream features could be affected.</p>
      <div class="title_division">Unforming multibend brackets</div>
      <p class="para_division">The multibend bracket unforms as a single unit. All bends are either formed or unformed.</p>
      <div class="title_division">Updating multibend brackets</div>
      <p class="para_division">As with any other feature, a multibend bracket will update if any of its parents (features, expressions, geometry) change. If the multibend bracket appears to have updated incorrectly, try unforming then forming the multibend bracket. This usually causes the feature to be rebuilt correctly.</p>
      <div class="title_division">Bend centerlines</div>
      <p class="para_division">The <b class="uiTerm">Multibend Bracket</b> creates bend center lines for each bend node. Since these lines are used as application curves for hidden bend features, all rules associated with that feature apply. At least part of the bend center line must lie within the outline of the sketch geometry. The bend center line must not extend past the outline such that when it is projected onto the extruded sketch, it will yield two curves. The system will center each bend center line based on the position on the first reference object selected.
      </p>
      <p class="para_division">The bend center lines cannot cross. If they do cross you must construct a relief while in the <b class="uiTerm">Sketcher</b>.
      </p>
      <div class="title_division">Determining bend direction</div>
      <p class="para_division"><b class="uiTerm">Multibend Bracket</b> computes the centroid of all reference geometry for each bend node and the base plane. It uses these positions to determine each bend direction (such as from right/left to up/down). If one of these centroids falls within a bend area, an error will be given. For best results, when selecting geometry, make sure the geometry clearly occupies one side of the bend. Note that when a datum plane is used as reference geometry, its origin is used to determine the bend direction. Since you don't have control over the origin of a datum plane, it is best to include addition geometry along with the datum plane so unexpected results can be avoided.
      </p>
      <div class="title_division">Gaps in sketches</div>
      <p class="para_division">The <b class="uiTerm">Sketch Tools</b> dialog box allows you to create or edit the sketch that defines the outer perimeter of a <b class="uiTerm">Multibend Bracket</b> feature. Since the sketch will be extruded, it is important to make sure there are no gaps in this perimeter. When you leave the <b class="uiTerm">Sketch Tools</b> dialog box, the system will extrude the sketch. If the extrusion failed, you will be shown the location of possible gaps in the outline. Reenter <b class="uiTerm">Sketch Tools</b> to correct these gaps. Gaps that are smaller than the <b class="uiTerm">Chaining Tolerance</b> will be ignored. You may set the <b class="uiTerm">Chaining Tolerance</b> under <b class="uiTerm">Preferences&rarr;Selection</b>.
      </p>
      <div class="title_division">Deleting sketch curves</div>
      <p class="para_division">Use the <b class="uiTerm">Sketch Tools</b> dialog box to edit the sketch of a <b class="uiTerm">Multibend Bracket</b> feature. While editing, note that you cannot delete active sketch curves that are part of the extrusion. To delete these curves, first change them to reference geometry using the <b class="uiTerm">Convert To/From Reference</b> function. Then exit the <b class="uiTerm">Sketch Tools</b> dialog box to cause the <b class="uiTerm">Multibend Bracket</b> to update. You may then reenter the <b class="uiTerm">Sketch Tools</b> dialog box to delete the unused sketch curves. 
      </p>
      <div class="title_division">Editing unfolded reference geometry in sketch</div>
      <p class="para_division">Do not attempt to edit, trim, or extend unfolded reference geometry in the sketch. If you do, the <b class="uiTerm">Sketcher</b> will warn you that some constraints and parameters may be removed. If you accept this, all associativity between the reference geometry and the sketch will be lost. Rather than edit the reference geometry directly, you should create new sketch geometry that is based on the reference geometry.
      </p>
      <div class="title_division">Handling bend lines in sketch</div>
      <p class="para_division">You should not add the <b class="uiTerm">Bend Tangent Lines</b>, <b class="uiTerm">Bend Centerlines</b>, or <b class="uiTerm">Intersection Lines</b> to the sketch. This can cause inferred constraints to be applied to these curves. When the sketch updates, such constraints could cause these bend lines to be repositioned improperly.
      </p>
      <div class="title_division">Bend limitations</div>
      <p class="para_division">There are certain limitations in the <b class="uiTerm">Bend</b> feature that apply to the multibend bracket. The bend area (the space between the two bend tangent lines) cannot be split by interior sketch curves (holes or cutouts). Likewise, the bend area cannot completely contain any interior cutouts. To get around these limitations, you can apply <b class="uiTerm">Bend</b>, <b class="uiTerm">Slot</b>, or <b class="uiTerm">Cutout</b> features to the bend area of the multibend bracket.
      </p>
      <p class="para_division">When defining the bends do not define a bend in such a manner that one edge of a bend shares an edge with another bend or base plane.</p>
      <div class="title_division">Self&ndash;forming features</div>
      <p class="para_division">There are two unforming methods available for Sheet Metal features. If you have <b class="uiTerm">Preferences&rarr;Sheet Metal&rarr;Use Self&ndash;Forming Features</b> enabled, then all newly created multibend brackets will have the ability to unform themselves using the <b class="uiTerm">Form/Unform</b> dialog box. When <b class="uiTerm">Preferences&rarr;Sheet Metal&rarr;Use Forming Operations</b> is enabled, you must unform using the <b class="uiTerm">Unbend</b> and <b class="uiTerm">Rebend</b> features. Note that you may apply the <b class="uiTerm">Unbend/Rebend</b> feature to a self&ndash;forming multibend bracket, however, it will loose its ability to form and unform. You can revert the multibend bracket back into a self&ndash;forming feature if you delete the <b class="uiTerm">Unbend</b> feature and use the <b class="uiTerm">Model Navigator</b> menu&rarr;<b class="uiTerm">Make Self&ndash;Forming Feature</b>.
      </p>
      <p class="para_division">For more information on <b class="uiTerm">Multibend Bracket</b> usage see Appendix A: <a class="links" href="javascript:void(0)" onclick="top.openFile('sheetmetaldes/appendix_enclosure.html');return(false);">Enclosure Part</a>.
      </p>
   </body>
</html>