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      <title>Curve/Point Drive Method</title>
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      <div class="title_topic4" id="xps10_pagetitle">Curve/Point Drive Method</div>
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      <p class="para_topic">The Curve/Point Drive Method enables you to define Drive geometry by specifying points and selecting curves. When specifying points, the Drive Path is created as linear segments between the specified points. When specifying curves, Drive Points are generated along the selected curves. In both cases, the Drive geometry is projected on to the Part Surfaces where the Tool Path is then created. The curves may be open or closed, contiguous or noncontiguous, planar or nonplanar.</p>
      <p class="para_topic">When points define the Drive geometry, the cutter moves along the Tool Path from one point to the next in the order in which they were specified. The same point may be used more than once, provided it is not defined consecutively in the sequence. A closed Drive Path, for example, can be created by defining the same point as the first and last point in the sequence.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/drvgeom_pts.gif"></p>
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      <div class="title_figure">Drive Geometry Defined by Points</div>
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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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               <div class="para_note">
                  <p class="para_note_body"> NOTE: If only one Drive Point is specified or if several Drive Points are specified such that when projected only one position is defined on the Part Geometry, a Tool Path will not be generated and an error message will be displayed.</p>
                  <p class="para_note_body"></p>
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      <p class="para_topic">When curves define the Drive Geometry, the cutter moves along the Tool Path from one curve to the next in the order in which they were selected. Selected curves may be contiguous or noncontiguous.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/drvgeom_crvs.gif"></p>
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      <div class="title_figure">Drive Geometry Defined by Curves</div>
      <p class="para_topic">Once you select the Drive geometry, a vector displays indicating the default cut direction. For open curves, the selected end determines the start point. For closed curves, the start point and cut direction are determined by the order in which the segments were selected.</p>
      <p class="para_topic">A negative stock value is sometimes used with this drive method to allow the tool to cut just below the selected Part Surface, creating a groove as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/neg_stock.gif"></p>
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      <div class="title_figure">Negative Stock</div>
      <p class="para_topic">The following options display in the Curve/Point Drive Method dialog box.</p>
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               <p class="para_th">Drive Geometry</p>
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               <p class="para_td">Selects and edits points and curves which will be used to define the tool path</p>
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            <th colspan="1" rowspan="1" valign="top">
               <p class="para_th">Cut Step</p>
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            <td colspan="1" rowspan="1" valign="top">
               <p class="para_td">Controls the distance between Drive Points created along the Drive Curve</p>
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               <p class="para_th">Tolerance</p>
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               <p class="para_td">Specifies the maximum allowable nor mal distance between the Drive Curve and the line extending between two con secutive Drive Points</p>
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            <th colspan="1" rowspan="1" valign="top">
               <p class="para_th">Projection Vector</p>
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               <p class="para_td">Determines how the Drive Points project to the Part Surface</p>
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               <p class="para_th">Display Drive Path</p>
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               <p class="para_td">Displays the Drive Path defined by the selected curve</p>
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      </table><br><div class="title_division">Drive Geometry</div>
      <p class="para_division">The Drive Geometry options enable you to select and edit points and curves which will be used to define the tool path. They also enable you to specify parameters for the selected drive geometry such as feed rates, lifts, and cut direction.</p>
      <div class="title_division">Select</div>
      <p class="para_division">Select enables you to initially select the drive geometry and specify parameters associated with drive geometry. You may select curves or points. When selecting points, the order in which the points are selected determines the cut direction. When selecting curves, the order in which the curves are selected determines the sequence in which they are cut, and the proximity in which each curve is selected determines the cut direction for that curve. The selected end of the curve defines the start point of the cut. Selected curves may be contiguous or noncontiguous. Noncontiguous curves will be connected by default with a connection line (cutting move).</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/detcutdir.gif"></p>
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      <div class="title_figure">Determining Cut Direction</div>
      <p class="para_division">This button toggles to Reselect once you have initially selected the drive geometry, enabling you to redefine the drive geometry and all associated parameters.</p>
      <p class="para_division">Custom Cut Feedrate enables you to assign a feed rate and feed rate unit to each selected curve and point. You must first specify the feed rate and unit and then select the point or curve to which they apply. For curves, the feed rate will be applied to the cutting move along the curve. Connection lines between noncontiguous curves or points assume the feed rate of the next curve or point in the sequence as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/detcutdirect.gif"></p>
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      <div class="title_figure">Determining Cut Direction</div>
      <p class="para_division">Local Lift at End enables you to specify non-cutting moves between noncontiguous curves. If this option is not activated, the system will generate a connection line (a straight line cut) between the curves. The retract is applied to the end of the selected curve and the engage is applied to the beginning of the next curve in the sequence. The non-cutting move will follow the parameters defined under the Non-Cutting option of the main dialog box.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/lift_appl_1selcurv.gif"></p>
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      <div class="title_figure">Lift Applied to the First Selected Curve</div>
      <p class="para_division">Geometry Type enables you to specify whether you wish to select individual curves, a chain of contiguous curves, or individual points. When selecting points, the order of selection determines the cut direction. When selecting individual curves, the order of selection determines the cut, and the proximity in which each curve is selected determines the cut direction. When selecting a chain of curves, you are prompted to select the start curve and the end curve. The proximity in which you select the end curve determines the cut direction for the entire chain as illustrated below.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/detcutdirctn.gif"></p>
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      <div class="title_figure">Determining Cut Direction</div>
      <p class="para_division">In the above illustration, the proximity in which the end curve is selected defines the tail of the directional vector for the entire chain.</p>
      <p class="para_division">Curve Name enables you to select points or curves by keying in their names.</p>
      <div class="title_division">Edit</div>
      <p class="para_division">Edit enables you to reselect drive geometry and respecify parameters associated with existing drive geometry.</p>
      <p class="para_division">Custom Feed Rate and Local Lift at End appear in the Curve/Point Selection dialog box and are described above. The remaining options are unique to this dialog box and are described below.</p>
      <p class="para_division">Action Mode enables you to either Edit existing drive geometry or Append additional geometry. Append redisplays the Curve/Point Selection dialog box described above. Edit enables you to use the Change Direction, Remove, and Reselect These options are described below.</p>
      <p class="para_division">Change Direction reverses the displayed directional vector of the current point or curve. The Previous and Next arrows enable you to specify the current point or curve.</p>
      <p class="para_division">Remove causes the system to no longer regard the current point or curve as drive geometry. The Previous and Next arrows enable you to specify the current point or curve.</p>
      <p class="para_division">Reselect All eliminates all drive geometry attributes and displays the Curve/Point Selection dialog box to allow you to redefine the drive geometry.</p>
      <div class="title_division">Display</div>
      <p class="para_division">Display highlights the current drive geometry.</p>
      <div class="title_division">Cut Step</div>
      <p class="para_division">Cut Step controls the distance between Drive Points created along the Drive Curve. The closer the Drive Points are, the more accurately the Tool Path follows the Drive Curve.</p>
      <p class="para_division">You can control the cut step by specifying a tolerance or by specifying a number of points.</p>
      <div class="title_division">Tolerance</div>
      <p class="para_division">Tolerance allows you to specify the maximum allowable normal distance between the Drive Curve and the line extending between two consecutive Drive Points. Drive points are generated in such a way that this normal distance does not exceed the specified tolerance. A very small tolerance causes many Drive Points to be created very close together. The more Drive Points you create, the more closely the tool follows the Drive Curve.</p>
      <div class="figure">
         <p align="center"><img align="bottom" src="graphics/detcutdir2.gif"></p>
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      <div class="title_figure">Cut Step Defined by Specifying a Tolerance</div>
      <p class="para_division">Number allows you to specify the minimum number of Drive Points to create along the Drive Curve. Additional points are created automatically if necessary for the Tool Path to follow the Part Surface Contours within the specified Part Surface Intol/Outol values.</p>
      <div class="title_division">Projection Vector</div>
      <p class="para_division">Projection Vector is an option common to most Drive Methods. It enables you to determine how the Drive Points project to the Part Surface.</p>
      <div class="title_division">Display Drive Path</div>
      <p class="para_division">Display Drive Path enables you to display the Drive Path defined by the selected curve. The path is created as a temporary element and is for visual reference only.</p>
      <div class="title_division">Example of Curve/Point Drive Method</div>
      <p class="para_division">Here is an example of how Curve/Point Drive Method works:</p>
      <ul>
         <li>
            <p class="para_item">Choose Curve/Point as the Drive Method.</p>
         </li>
         <li>
            <p class="para_item">Choose the Select button to define the Drive Geometry.</p>
         </li>
         <li>
            <p class="para_item">Specify the Feed Rate and Local Lift.</p>
         </li>
         <li>
            <p class="para_item">Specify Curve Chaining as the selection method.</p>
         </li>
         <li>
            <p class="para_item">Select a as the start curve and z as the end curve and OK. Where you select z determines the cut direction.</p>
         </li>
      </ul>
      <p align="center"><img align="bottom" src="graphics/strtend_curve.gif"></p>
      <ul>
         <li>
            <p class="para_item">Choose Tolerance for the Cut Step and key in .005 .</p>
         </li>
         <li>
            <p class="para_item">Define the Project Vector as Fixed using points b and c.</p>
         </li>
         <li>
            <p class="para_item">Select OK in the Curve/Point Drive Method dialog box.</p>
         </li>
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