What are these lines?

(On the second pic)

How do they form and what do they affect? I know that seams affect UV maps, this does not look like them though…

How may I select them? How may I benefit from them?

Also, for some, reason, this area is not affected by subsurf?

Thanks for the reaply guys.



Edges have a crease value https://www.blender.org/manual/modeling/modifiers/generate/subsurf.html#modifiers-generate-subsurf-creases

Ah sweet, thanks a lot man