This feature is available in the Mesh Edit menu or the context menu, if you right-click on the screen. It refines the triangle mesh, minimizing the maximum edge length to a new value which must be specified in the dialog box. Below are the information about the size of the selected faces and the length of the longest edge. It helps you to find appropriate values for the triangle refinement.
The dialog box for refining the triangle mesh.
You can either refine the triangle mesh of the whole part or, by ticking the box in the dialog, only refine selected triangles.
The existing triangles are split into smaller triangles until no triangles with too long edges remain. The number of triangles increases, often dramatically. The shape and outer appearance of the part is not changed during this process. However, a refinement of the triangle mesh can be essential for subsequent operations, such as making a selection or smoothing triangles.
The triangle mesh of the selected side walls of this cube is refined.