How can I get Tangential direction Vector in Python
<p>I can get some info from a Arc.</p>

<ul>
<li>FirstPoint ã [x,y,z]</li>
<li>LastPoint  ã [x,y,z]</li>
<li>Center ãã   [x,y,z]</li>
<li>Axis   ãã ã [x,y,z] # Perpendicular to the plane</li>
</ul>

<p>How can I get the FirstPoint&amp;LastPoint's tangential direction Vector ?</p>

<p>I want to get a intersection Point from two direction vector.</p>

<p>PS: Work in FreeCAD.</p>

<p>Thanks for any reply</p>

<p>best regards,
Eason</p>

<p>s.Curve</p>

<pre><code>Circle (Radius : 1, Position : (0.335157, 11.988, 5.55452), Direction : (-0.914329, -0.257151, 0.312851))
</code></pre>

<p>s.Vertex1.Point  #FirstPoint</p>

<pre><code>Vector (0.7393506936636021, 11.360676836326173, 6.220155663200929)
</code></pre>

<p>s.Vertex2.Point  #LastPoint</p>

<pre><code>Vector (0.3602513339713556, 12.723079925995924, 6.232050903393676)
</code></pre>

<p>s.Curve.FirstParameter</p>

<p><code>0.0</code></p>

<p>s.Curve.LastParameter</p>

<pre><code>6.283185307179586
</code></pre>

<p>It's a simple arc.</p>

python math direction freecad