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

https://wiki-cable.win/index.php/Line_Set_Length_Rules_for_Efficient_Mini_Split_Performance

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.