## Description

The unstructured domain solver's grid control parameters provided in the *Quads* frame (see figure below) allow you to establish the criteria by which
the solver decides whether and how to combine triangular cells into quads.

Use the Quads frame to specify the criteria used by the unstructured domain solver to decide whether triangular cells should be combined into quads.

**Note:** The attributes in the *Quads* frame have no impact if the
*Algorithm* is set to *Thin Surface
Interpolation*. However, they are still used when *Thin Surface
Interpolation* cannot be applied and the *Algorithm* defaults to *Advancing Front
Ortho*.

When the unstructured domain solver uses either the *Delaunay* or the *Advancing Front* algorithms (refer to
the Algorithm section for more information), the generation of quad-dominant domains involves two steps: first, the domain is
triangulated, and second, the triangular cells are combined to form quadrilateral cells wherever possible. The *Quads* frame provides tools to decide
whether two triangular cells can be combined into a quadrilateral cell.

*Quad Max. Included Angle* lets you specify the maximum included angle allowed for quadrilateral cells. This parameter prevents the combination of
triangular cells if the included angle of the final quadrilateral cell is larger than the specified value.

*Quad Max. Warp Angle* lets you specify the maximum warpage allowed for quadrilateral cells. This parameter prevents the combination of triangular
cells if the warpage of the final quadrilateral cell is larger than the specified value.