Percent of Tetrahedra Refined Per Pass
The value you set for Percent Refinement Per Pass determines how many tetrahedra are added at each iteration of the adaptive refinement process. For instance, entering 30 causes the mesh to increase approximately 30 percent each pass. The tetrahedra with the highest error will be refined. If your mesh consisted of 1000 elements, the tetrahedra would be refined so that 300 new elements are added to the mesh. Generally, you can accept the default value.