To Detect Entities that Form Closed Loops
Use the Shade Closed Loops diagnostic tool to detect closed loops formed by sketched entities. A closed loop is a chain of entities that form a section that you can use to create a solid extrusion. For 3D sketch geometry, only the closed loops formed by valid entities appear shaded. Closed loops formed by construction geometry are not shaded.
If the sketch contains several closed loops that are internal and external to each other, the outermost loop is shaded, and the shading of the internal loops is alternated. For a sketch with multiple Sketcher groups, the criteria to identify a closed loop is applied to each group independently.
Closed loops are shaded by default. To disable the Shade Closed Loops tool, perform one of these operations:
• Click > > 
Shade Closed Loops.
Shade Closed Loops.In 2D Sketcher, click > 
Inspection Tools > Shade Closed Loops or click > Shade Closed Loops.
Inspection Tools > Shade Closed Loops or click > Shade Closed Loops.• On the Graphics toolbar, click Inspection Tools Display Filters > Shade Closed Loops.
Inspection Tools Display Filters > Shade Closed Loops.• Click > 
Options > > .
Options > > .• Set the sketcher_shade_closed_loops configuration option to no.
To set the color of the shading, click > Options > > > .
Options > > > .