In CFD analysis, we sometimes have to resolve small gaps between either edges or faces — for example, the fins of a heat sink. Meshing the fin regions is important to estimate the overall heat transfer from the heat sink base to the fluid around it. The Ansys Fluent Meshing Watertight Geometry Workflow offers a local sizing control, the Proximity, for exactly this purpose in the “Add Local Sizing” task. In this lesson, we will learn about the effect of this “proximity” sizing control on the imported CAD or mesh geometries. In addition to understanding the four main parameters for setting the curvature sizing, namely the min and max sizes, the growth rate, and cells per gap, we will also demonstrate their influence on the generated surface mesh using an easy-to-follow workshop.