-<li>The next N lines describe nodes coordinates. Each line holds 2
-coordinates of a node.</li>
-
-<li>A key-points line: indices of nodes to be mapped on geometrical
-vertices. An index n refers to a node described on an n-th line of
-section 2. The first node index is zero.</li>
-
-<li>The rest lines describe nodal connectivity of elements, one line
-for an element. A line holds indices of nodes forming an element. An
-index n refers to a node described on an n-th line of the section
-2. The first node index is zero. There must be 3 or 4 indices on a
-line: only 2d elements are allowed.</li>
-</ol>
-
-The 2D pattern must contain at least one element and at least one
-key-point. All key-points must lay on boundaries.
-
-An example of a simple smp file and a preview of a pattern described
-in this file:
-
-\image html image94.gif
+-# The first line indicates the total number of pattern nodes (N).
+-# The next N lines describe nodes coordinates. Each line contains 2
+node coordinates for a 2D pattern or 3 node cordinates for a 3D pattern.
+Note, that node coordinates of a 3D pattern can be defined only by relative values in range [0;1].
+-# The key-points line contains the indices of the nodes to be mapped on geometrical
+vertices (for a 2D pattern only). Index n refers to the node described
+on the n-th line of section 2. The index of the first node zero. For a 3D pattern the key points are not specified.
+-# The remaining lines describe nodal connectivity of elements, one line
+for each element. Each line holds indices of nodes forming an element.
+Index n refers to the node described on the n-th line of section 2.
+The first node index is zero. There must be 3 or 4 indices on each
+line for a 2D pattern (only 2d elements are allowed) and 4, 5, 6 or 8
+indices for a 3D pattern (only 3d elements are allowed).
+
+A 2D pattern must contain at least one element and at least one
+key-point. All key-points must lie on boundaries.
+
+A 3D pattern must contain at least one element.
+
+An example of a simple 2D pattern smp file:
+
+\code
+!!! SALOME 2D mesh pattern file
+!!!
+!!! Nb of points:
+9
+ 200 0 !- 0
+ 100 0 !- 1
+ 0 0 !- 2
+ 0 -100 !- 3
+ 0 -200 !- 4
+ 100 -200 !- 5
+ 200 -200 !- 6
+ 200 -100 !- 7
+ 100 -100 !- 8
+!!! Indices of 4 key-points
+ 2 0 4 6
+!!! Indices of points of 6 elements
+ 0 1 8
+ 8 5 6 7
+ 2 3 8
+ 8 3 4 5
+ 8 7 0
+ 8 1 2
+\endcode
+
+The image below provides a preview of the above pattern:
+
+\image html pattern2d.png
+
+An example of a simple 3D pattern smp file:
+
+\code
+!!! SALOME 3D mesh pattern file
+!!!
+!!! Nb of points:
+9
+ 0 0 0 !- 0
+ 1 0 0 !- 1
+ 0 1 0 !- 2
+ 1 1 0 !- 3
+ 0 0 1 !- 4
+ 1 0 1 !- 5
+ 0 1 1 !- 6
+ 1 1 1 !- 7
+ 0.5 0.5 0.5 !- 8
+!!! Indices of points of 6 elements:
+ 0 1 5 4 8
+ 7 5 1 3 8
+ 3 2 6 7 8
+ 2 0 4 6 8
+ 0 2 3 1 8
+ 4 5 7 6 8
+\endcode