[Gmsh] Quadrangles and Q1 shape functions

Véronique et Christophe Geuzaine geuzaine.rochus at gmail.com
Thu Sep 24 21:43:25 CEST 2015


> On 24 Sep 2015, at 15:52, Torquil Macdonald Sørensen <torquil at gmail.com> wrote:
> 
> Hi!
> 
> I have a MSH file for a mesh of one quadrangle and four associated
> scalar field node values. Looking at the GMSH visualization, it uses two
> triangles to define the function shape inside the quadrangle, and it
> seems to use P1 shape functions within each triangle.
> 
> Is it possible to have GMSH not use any triangles for the visualization,
> but instead assume that the scalar field should be represented with Q1
> shape functions inside the quadrangle?
> 

Yes: select "Adapt visualization grid" in the options of the view. (Set the target error to a negative number to force subdivisions all the way to the maximum recursion level.)




> Here is the MSH file, and the screenshot is attached:
> 
> $MeshFormat
> 2.2 0 8
> $EndMeshFormat
> $Nodes
> 4
> 1 0.0 0.0 0.0
> 2 1.0 0.0 0.0
> 3 1.0 1.0 0.0
> 4 0.0 1.0 0.0
> $EndNodes
> $Elements
> 1
> 1 3 2 99 2 1 2 3 4
> $EndElements
> $NodeData
> 1
> "A scalar view"
> 1
> 0.0
> 3
> 0
> 1
> 4
> 1 0.0
> 2 1.0
> 3 0.0
> 4 0.0
> $EndNodeData
> 
> Best regards and thanks,
> Torquil Sørensen
> <quadrangle.png>_______________________________________________
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> gmsh at geuz.org
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