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      <title>System Conventions</title>
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      <div class="title_topic2" id="xps10_pagetitle">System Conventions</div>
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      <p class="para_topic">This section describes several NX conventions that are used throughout the system.</p>
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               <p class="para_th">Convention</p>
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               <p class="para_th">Description</p>
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               <p class="para_td">Coordinate Systems</p>
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               <p class="para_td">NX allows planes and coordinate systems to be defined for constructing other geometry. These planes and coordinate systems are completely independent of the viewing direction. Geometry may be created on planes that are not parallel to the screen.</p>
               <p class="para_td">The absolute coordinate system, or model space, is the coordinate system in use when a new model is started. The viewing direction is along the positive Z-axis, towards the origin. Other coordinate systems may be defined, but one particular coordinate system called the work coordinate system (WCS) is used for construction. </p>
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               <p class="para_td">Angle Measurement</p>
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               <p class="para_td">NX measures angles in a counterclockwise direction from the positive X (or XC) axis to the positive Y (or YC) axis.</p>
               <p class="para_td">Angular measurements are entered as degrees and decimal fractions of a degree. When you enter a positive value, the angle is measured counterclockwise from the positive X-axis or a specified base line. When you enter a negative value, the system displays a minus sign (-) to indicate movement in a clockwise direction. </p>
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               <p class="para_td">Right-Hand Rule</p>
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               <p class="para_td">The right-hand rule is used to determine the direction of rotation and the orientation of coordinate systems. This rule also determines clockwise and counterclockwise directions.</p>
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