In 3D modeling, a line set defines which edges are rendered as strokes in a non-photorealistic style

https://aesiro.com.br/wiki/index.php/Choosing_the_Best_Copper_Line_Set_for_a_New_Installation

In 3D modeling, a line set defines which edges are rendered as strokes in a non-photorealistic style, controlling visibility, crease emphasis, silhouette extraction, and intersection highlights for stylized visuals.