Review Element Quality
Use the Element Quality view to review element quality while simultaneously editing your model.
The Element Quality view is automatically enabled when creating and editing surface
mesh. To manually enable the Element Quality view, click 
on the View Controls toolbar and select Surface
Element Quality.
When the Element Quality view is enabled, elements are colored based on their quality, which is defined by the 2D element criteria settings. A moveable legend displays in the modeling window to assist you in evaluating the element quality. A summary of the model's Compound QI and number/percentage of failed elements is also displayed under the legend.