The mesh resolution and mesh element quality are important aspects to consider when validating a model. Low mesh resolution — in relation to the variations in the solution and the geometry — can lead to inaccurate results. A low mesh element quality — which measures the regularity of the mesh elements’ shapes — can lead to inverted mesh elements (see Avoiding Inverted Mesh Elements) and to high condition numbers for the Jacobians, which in turn can cause convergence issues.
COMSOL Multiphysics includes built-in variables for these mesh quantities:
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h, the local mesh size
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qual, the mesh element quality, which is a dimensionless quantity between 0 and 1, where 1 represents a perfectly regular element and 0 represents a degenerated element.
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). This creates a plot group with a 
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By default, this plot shows the mesh element quality. In the Settings window for Mesh, select Size instead of Quality from the Element color list to plot the mesh element size instead.
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Alternatively, you can access the built-in variables for mesh element quality (qual) and mesh element size (h) in a surface plot, for example:
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), right-click 
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Add a 2D or 3D Plot Group using the Mesh data set as the group’s data set, and then add a Surface or Volume plot. For example, in a 2D Plot Group>Surface node (
 ), select Element size (h) or Element quality (qual) from the predefined quantities (under Mesh). Then click the Plot button ( ). |
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