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    <td width="10" height="272" valign="top" bgcolor="#DDDDDD"><p>&nbsp;</p>    </td>
    <td width="173" valign="top" bgcolor="#DDDDDD"><p class="Normal"><a href="index.html">Home</a></p>
      <p class="Normal">If you're new to Python <br />
      and VPython: <a href="VisualIntro.html">Introduction</a></p>
      <p class="Normal">A VPython <a href="VPython_Intro.pdf" target="_blank">tutorial</a></p>
      <p class="Normal"><a href="primitives.html">Pictures</a> of 3D objects</p>
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    <p class="Normal"><a href="new_features.html">What's new</a></p>
    <p class="Normal"><a href="http://vpython.org" target="_blank">Classic VPython web site</a><br />
      <a href="license.txt" target="_blank">VPython license</a><br />
      <a href="http://www.python.org" target="_blank">Python web site</a> <br /></p></td>
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          <td width="77%"><div align="center"><span class="style1 style2"><font color="#0000A0">arrow</font></span></div></td>
          <td width="23%"><img src="images/arrow.jpg" alt="arrow" width="130" height="127" /></td>
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        <p class="Normal"> <img src="VisualRef-2.gif" alt="arrow" align="right" /> The arrow object has a straight box-shaped shaft with an arrowhead at one end. The following statement will display an arrow pointing parallel to the x axis:</p>
        <div>
          <p class="program"> pointer = arrow(pos=vector(0,2,1), &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;axis=vector(5,0,0), shaftwidth=1)</p>
          <p class="Normal"> The arrow object has the following attributes and
            default  values, like those for cylinders: <span class="attribute">pos<font color="#000000"> (0,0,0)</font></span>, <span class="attribute">axis<font color="#000000"> (1,0,0)</font></span>, <span class="attribute">length<font color="#000000"> (1)</font></span>, <span class="attribute">color<font color="#000000"> (1,1,1)
             which is color.white</font></span>, <span class="attribute">red<font color="#000000"> (1)</font></span>, <span class="attribute">green<font color="#000000"> (1)</font></span>, <span class="attribute">blue<font color="#000000"> (1)</font></span>,
             <span class="attribute">opacity</span> (1),
             <span class="attribute">shininess</span> (0.6), <span class="attribute">emissive</span> (False), <a href="../GlowScriptDocs/textures.html"><strong>texture</strong></a>,
             and <span class="attribute">up<font color="#000000"> (0,1,0)</font></span>.
              As with <a href="box.html">box</a>, the <span class="attribute">up</span> attribute
              is significant for arrow  because the shaft and head have square
              cross sections, and setting the <em class="program"> </em><span class="attribute">up</span> attribute
              rotates the arrow about  its axis. Additional arrow attributes:</p>
          <p class="attributes"> <span class="attribute">shaftwidth</span> By default, shaftwidth 
            = 0.1*(length of arrow)</p>
          <p class="attributes"> <span class="attribute">headwidth</span> By default, headwidth 
            = 2*shaftwidth</p>
          <p class="attributes"> <span class="attribute">headlength</span> By default, headlength 
            = 3*shaftwidth</p>
          <p class="Normal">Assigning <span class="attribute">shaftwidth = 0</span> makes it be the default (0.1 times the length of the arrow). If you don't explicitly set <span class="attribute">headwidth</span> or <span class="attribute">headlength</span>, its length is based as shown above on <span class="attribute">shaftwidth</span> (either the default or whatever value you specify for <span class="attribute">shaftwidth</span>). If <span class="attribute">headlength</span> becomes larger than half the length of the arrow, or the shaft becomes thinner 
          than 1/50 the length, the entire arrow is scaled accordingly.</p>
          <p class="Normal">This default behavior makes the widths of very short
            arrows  shrink, and the widths of very long arrows grow (while displaying
            the correct  total length). If you prefer that <span class="attribute">shaftwidth</span> and <span class="attribute">headwidth</span> not
            change as the arrow gets  very short or very long, specify the desired <span class="attribute">shaftwidth</span>. 
            In this case the only adjustment that is made is that <span class="attribute">headlength</span> is
            adjusted so that it never gets longer than half the total length,
            so  that the total length of the arrow is correct. This means that
            very short,  thick arrows look similar to a thumbtack, with a nearly
            flat head.</p>
          <p class="Normal">Note that the <span class="attribute">pos</span> attribute 
            for cylinder, arrow, cone, and pyramid corresponds to one end of the object, 
            whereas for a box, sphere, or ring it corresponds to the center of the object. </p>
          <p class="Normal">If you include <span class="attribute">make_trail=True</span> when you create the object, a trail will be left behind the object as you move it. For related options, see <a href="trail.html"><strong>Leaving a Trail</strong></a>.</p>
          <p class="Normal">See <a href="rotation.html"><strong>Rotating an Object</strong></a> for an easy way to change the orientation of an object.</p>
<p class="Normal">See description of <a href="options.html">Additional
              Attributes</a> available for all 3D display objects.</p>
          <p class="Normal">&nbsp; </p>
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