\page extrusion_along_path_page Extrusion along Path
\n In principle, <b>Extrusion along Path</b> works in the same way
-as \ref extrusion_page "Extrusion", the main difference is that we define not a vector,
-but a path of extrusion which must be a 1D mesh or 1D sub-mesh.
+as \ref extrusion_page "Extrusion", the main difference is that we
+define not a vector, but a path of extrusion which must be an 1D mesh
+or 1D sub-mesh.
To get an idea of how this algorithm works, examine several examples,
starting from the most simple case of extrusion along a straight edge.
In the examples the sample mesh will be extruded along different
mesh.</center>
\image html circle_angles_after.png
-<center>The same, but using angles {45, -45, 45, -45, 45, -45, 45,
--45}</center>
+<center>The same, but using angles {45, -45, 45, -45, 45, -45, 45, -45}
+</center>
<br><em>To use Extrusion along Path:</em>
<ol>
of following means:
<ul>
<li><b>Select the whole mesh, sub-mesh or group</b> activating this
- checkbox.</li>
+ check-box.</li>
<li>Choose mesh elements with the mouse in the 3D Viewer. It is
possible to select a whole area with a mouse frame.</li>
<li>Input the element IDs directly in <b>Node IDs</b>, <b>Edge
<li>Define the \b Path along which the elements will be extruded.<br>
Path definition consists of several elements:
<ul>
- <li><b>Mesh or submesh</b> - 1D mesh or sub-mesh, along which
+ <li><b>Mesh or sub-mesh</b> - 1D mesh or sub-mesh, along which
proceeds the extrusion.</li>
- <li><b>Start node</b> - the start node. It is used to define
- the direction of extrusion. </li>
+ <li><b>Start node</b> - the start node of the Path. It is used
+ to define the direction of extrusion. </li>
</ul>
</li>
<li>If you activate <b>Generate Groups</b> check-box, the <em>result elements</em>
<li>If the path of extrusion is curvilinear, at each iteration the
extruded elements are rotated to keep its initial angularity to the
curve. By default, the <b>Base Point</b> around which the elements
- are rotated is the mass center of the elements, however, you can
- specify any point as the <b>Base Point</b> and the elements will be
- rotated with respect to this point.<br>
+ are rotated is the mass center of the elements (note that it can
+ differ from the gravity center computed by \a Geometry module for the
+ underlying shape), however, you can specify any point as the <b>Base
+ Point</b> and the elements will be rotated with respect to this
+ point.<br>
Note that only the displacement of the <b>Base Point</b> exactly
equals to the path, and all other extruded elements simply keep
their position relatively to the <b>Base Point</b> at each
<b>Linear variation of the angles</b> option allows defining the angle
of gradual rotation for the whole path. At each step the elements will
-be rotated by <code>angle / nb. of steps</code>.
+be rotated by <code>( angle / nb. of steps )</code>.
</li>
</ul>
</li>
