\n Projection algorithms allow to define the mesh of a geometrical
object by the projection of another already meshed geometrical object.
-<b>Projection 1D</b> algorithm permits to define the mesh of an edge
+<b>Projection 1D</b> algorithm allows to define the mesh of an edge
(or group of edges)
by the projection of another already meshed edge (or group of edges).
\n To apply this algorithm select the edge to be meshed (indicated in
\image html projection_1d.png
-In this menu you can define the \b Name of the algorithm, the algeady
-meshed source \b Edge and the \b Mesh (optional, use it if there are several
-different meshes on the same edge). It could also be necessary to
-define the orientation of edges, which is done by indicating the
-<b>Source Vertex</b> being the first point of the Source Edge and the
-<b>Target Vertex</b> being the first point of the created \b Edge. For
-a group of edges, <b>Source</b> and <b>Target</b> vertices should be
-shared by only one edge of the group. If <b>Source</b> and
-<b>Target</b> vectors are specified, the elements of the group must be ajacent.
-
-\n <b>Projection 2D</b> algorithm permits to define the mesh of a face
-(or group of faces) by the
-projection of another already meshed face (or group of faces). This
-algorithm works only
-if all edges of the target face have been meshed as 1D Projections of
-the edges of the source face.
+In this dialog you can define
+<ul>
+ <li> the \b Name of the algorithm,</li>
+ <li> the already meshed <b> Source Edge</b> and </li>
+ <li> the <b>Source Mesh </b> (It can be omitted only when projecting
+ a sub-mesh on another one of the same Mesh).</li>
+ <li> It could also be necessary to define the orientation of edges,
+ which is done by indicating the <b>Source Vertex</b> being the
+ first point of the <b>Source Edge </b>and the <b>Target Vertex</b> being
+ the first point of the edge being meshed.</li>
+</ul>
+<br>
+For a group of edges, <b>Source</b> and <b>Target</b> vertices should be
+shared by only one edge of the group. If <b>Source</b> and <b>Target</b>
+vertices are specified, the edges in the group must be connected.
+The source and target groups must contain equal number of edges
+and they must form topologically equal structures.
+
+\n <b>Projection 2D</b> algorithm allows to define the mesh of a face
+(or group of faces) by the projection of another already meshed face
+(or group of faces). This algorithm works only if all edges of the
+target face have been discretized into the same number of
+segments as corresponding edges of the source face.
To apply this algorithm select the face to be meshed (indicated in the
field \b Geometry of <b>Create mesh</b> dialog box), <b>Projection
-2D</b> in the list
-of 2D algorithms and click the <em>"Add Hypothesis"</em> button. The
-following dialog box will appear:
+2D</b> in the list of 2D algorithms and click the <em> "Add
+Hypothesis"</em> button. The following dialog box will appear:
\image html projection_2d.png
-In this menu you can define the \b Name of the algorithm, the algeady
-meshed source \b Face and the \b Mesh (optional, use it if there are several
-different meshes on the same face). It could also be necessary to
-define the orientation of mesh on the face, which is done by
-indicating two <b>Source Vertices</b>, which belong to the same edge of the
-source face, and two <b>Target Vertices</b>, which belong to the same edge of
-the created \b Face.
+In this dialog you can define
+<ul>
+ <li> the \b Name of the algorithm, </li>
+ <li> the already meshed <b> Source Face </b> and </li>
+ <li> the <b> Source Mesh </b> (It can be omitted only when
+ projecting a submesh on another one of the same Mesh). </li>
+ <li> It could also be necessary to define the orientation of mesh on
+ the face, which is done by indicating two <b>Source Vertices</b>,
+ which belong to the same edge of the <b>Source Face</b>, and
+ two <b>Target Vertices</b>, which belong to the same edge of the
+ face being meshed.</li>
+</ul>
+
+The groups of faces are suitable for this algorithm only if they
+contain an equal number of faces and form topologically equal
+structures.
-\n <b>Projection 3D</b> algorithm permits to define the mesh of a shape by
+\n <b>Projection 1D-2D</b> algorithm differs from <b>Projection 2D</b>
+algorithm in one aspect: it generates mesh segments on edges of
+the face according to the projected 2D elements; thus it does not
+require the edges to be meshed by any other 1D algorithm; moreover it
+does not allow to mesh edges of the face using another algorithm via
+definition of sub-meshes.
+
+\n <b>Projection 3D</b> algorithm allows to define the mesh of a shape by
the projection of another already meshed shape. This algorithm works
-only if all faces and edges of the target face have been meshed as 1D
-Projections of the faces and edges of the source face. Another
+only if all faces and edges of the target shape have been meshed as 1D-2D
+Projections of the faces and edges of the source shape. Another
limitation is that this algorithm currently works only on boxes.
To apply this algorithm select the solid to be meshed (indicated in
\image html projection_3d.png
-In this menu you can define the \b Name of the algorithm, the algeady
-meshed source <b>3D shape</b> and the \b Mesh (optional, use it if there are
-several different meshes on the same shape). It could also be
-necessary to define the orientation of mesh on the shape, which is
+In this menu you can define the \b Name of the algorithm, the already
+meshed source <b>3D shape</b> and the \b Mesh (It can be omitted only when
+projecting a submesh on another one from the same global Mesh).
+It could also be necessary to define the orientation of mesh on the shape, which is
done by indicating two <b>Source Vertices</b>, which belong to the same edge
of the source <b>3D Shape</b>, and two <b>Target Vertices</b>, which belong to the
same edge of the source <b>3D Shape</b>.
+<br><b>See Also</b> a sample TUI Script of a
+\ref tui_projection "Projection Algorithms".
+
*/
