Specifying sculpting radius values
SketchUp determines the number of vertices included in the sculpting operation based on a radius value. The larger the radius the more vertices included in the sculpt. The Measurements toolbar displays this radius while you are sculpting a TIN. You can also specify a radius value while sculpting, such as 10'r, using the Measurements toolbar.
Tip: Preselect a series of points, faces, and edges within your TIN to sculpt more specific shapes such as ridges and berms.