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

https://danteuhmm162.hexaforgey.com/posts/ac-line-set-maintenance-tips-for-long-term-reliability

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.