You can hide or unload parts in order to make them invisible in the view. When you hide parts, the files are loaded and their geometry remains in the memory. When you unload parts, their geometry is removed from the local memory and unsaved changes are lost. You can unload hidden parts.

The check boxes and icons alongside part names in the structure tree indicate the loaded state and visibility state of the parts. Use the check boxes to show or hide selected parts in the view. Use Load or Unload commands on the Ribbon or shortcut menu to load or unload selected parts from memory.