smesh/doc/salome/gui/SMESH/input/additional_hypo.doc

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\page additional_hypo_page Additional Hypotheses

\n <b>Additional Hypotheses</b> can be applied as a supplement to the
main hypotheses, introducing additional concepts to mesh creation.

To define an <b>Additional Hypothesis</b> simply select it in
<b>Create Mesh</b> menu. These hypotheses are actually changes in the
rules of mesh creation and as such don't possess adjustable values.

<h2>Non Conform mesh allowed hypothesis</h2>

<b>Non Conform mesh allowed</b> hypothesis allows to generate non-conform
meshes (that is, meshes having some edges ending on an edge or face of
adjacent elements).

<h2>Quadratic Mesh</h2>

Quadratic Mesh hypothesis allows to build a quadratic mesh (whose
edges are not straight but broken lines and can be defined by three
points: first, middle and last) instead of an ordinary one.

<h2>Propagation of 1D Hypothesis on opposite edges</h2>

<b>Propagation of 1D Hypothesis on opposite edges</b> allows to propagate a
hypothesis onto an opposite edge. If a local hypothesis and
propagation are defined on an edge of a quadrangular face, the
opposite edge will have the same hypothesis, unless another hypothesis
has been locally defined on the opposite edge.
 
<br><b>See Also</b> a sample TUI Script of a 
\ref tui_propagation "Propagation hypothesis" operation

<h2>Quadrangle Preference</h2>

This additional hypothesis can be used together with Quadrangle (Mapping) and Netgen 2D
algorithms. 

It allows Netgen 2D to build quadrangular meshes at any conditions.

It allows Quadrangle (Mapping) to build quadrangular meshes even if the number
of nodes at the opposite edges of a meshed face is not equal,
otherwise this mesh will contain some triangular elements.
<br>
This hypothesis has one restriction on its work: the total quantity of
segments on all four sides of the face must be even (divisible by 2).

<h2>Triangle Preference</h2>

This additional hypothesis can be used only together with Quadrangle (Mapping)
algorithm. It allows to build triangular mesh faces in the refinement
area if the number of nodes at the opposite edges of a meshed face is not equal,
otherwise refinement area will contain some quadrangular elements.
 

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