Need help, map looks weird

Well, I’m a bit new to mapping and my map has all these weird lines in a tunnel I made.

http://filesmelt.com/dl/plaza0000.jpg

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I’ve gotten these before. Is the tunnel just one brush?
If it is, I believe it is a problem with source

If it isn’t I think you should remake the brushes that make up the tunnel where the white lines are.
If you decide to listen to me, atleast wait a few more posters to get more input. I’m just going off personal experiences.

It’s all 1 brush

I’m 80% sure its a problem with source. I might be wrong though.

Yea, that’s a typical source problem, I am still looking for a solution for this though. It’s getting rather annoying.

Post a screenshot of how it looks in hammer.

Really helpful… OFCOURSE ITS SOURCE PROBLEM.

I suggest placing skybox outside of tunnel and brush with blocklight texture inside walls.

Those lines are an issue with Source. For some reason, those lines become visible wherever visleafs are cut…