About Lightweight Holes
Lightweight holes are graphical representations of standard holes. To reduce memory usage, use lightweight holes for a large number of holes. A large number of standard holes (for example, more than 5,000) can cause Creo+ to run out of memory. Take this into account when converting lightweight holes to standard holes. Lightweight holes display as a diameter and axis on the bottom side of the board and are identified by 
in the Model Tree.
in the Model Tree.Set the configuration options ecad_mtg_hole_import and ecad_tool_hole_import to as lightweight to import ECAD MTG type holes and TOOL type holes as lightweight by default.
For more information, search the Help Center.