Part Modeling > Engineering Features > Hole > About Lightweight Holes
  
About Lightweight Holes
You can convert the geometry of a simple hole from solid to lightweight, and vice versa, at any time in Part mode. A lightweight hole can be used exactly as you would a hole with solid geometry, including for searches, in patterns, and as part of user-defined features.
Lightweight holes are represented in the graphics window by an orange circular curve and an axis. The curve follows the hole circumference and lies on the hole placement plane. In the Model Tree, lightweight holes are represented by the glyph.
 
* Model mass calculations do not include lightweight holes.