in the FeatureManager design
tree.Lightweight drawings are analogous to lightweight assemblies. When a drawing is lightweight, only a subset of its model data is loaded in memory. The remaining model data is loaded as needed.
Performance of drawings of large assemblies is improved significantly with lightweight drawings. Loading a lightweight drawing is faster than loading the same drawing with fully resolved parts.
Lightweight drawings are efficient because the full model data is loaded only as it is needed.
To load a drawing as lightweight:
When you open a drawing, select Lightweight in the Open dialog box.
To set assembly components to lightweight or resolved:
Right-click a component and select Set to Lightweight or Set to Resolved.
When a component is lightweight, a feather
appears on the part icon in the FeatureManager design
tree.
To set drawing views to lightweight or resolved:
Right-click a drawing view and select Set Resolved to Lightweight or Set Lightweight to Resolved.
A feather in the FeatureManager design tree also indicates lightweight
views 
.
Detached drawings cannot be lightweight drawings.
With lightweight drawings, you can:
Create all types of drawing views
Attach annotations to models in views
Dimension models in views
Specify edge properties
Select edges and vertices
Set drawings of sub-assemblies to lightweight or resolved
If you print a lightweight drawing when it is out of synchronization with its model, the drawing prints with a watermark:
SolidWorks Lightweight drawing - Out-of-Date Print