Pick Tools, Options and within the System Options there is a category on the left side titled Assemblies. The settings here are not unique; they are settings available throughout the System Options. These options all deal with how an assembly is:
- Loaded (lightweight)
- Viewed (No edges in shaded, Hide all sketches, Remove detail on rotation)
- Drawn (Hiding internal components, Hide view on drag)
If a file has been saved with this setting or the threshold set in the options has been passed, the assembly will load with these settings. To turn them off after loading, go to Tools, Large Assembly Mode. This is a toggle (on or off) option.