In Blender’s Freestyle, a line set filters which edges are drawn using criteria like visibility, face marks

https://garrettouzs054.image-perth.org/what-makes-a-high-quality-hvac-line-set-worth-it

In Blender’s Freestyle, a line set filters which edges are drawn using criteria like visibility, face marks, and material boundaries, allowing separate stroke styles for silhouettes and creases.