Strange ulgy render despite good model

Hey, I got this render from the entrance of a pyramid, egyptian style, made it over the past few days. The trouble is, despite the smoothed surface being strainght and the edges also straight, the render, as you can see shows some white seams at the sides. What are those stuff? I can’t seem to get rid of them. There’s no extra faces, and the edges are straight. Here is the pic:
http://img514.imageshack.us/my.php?image=33886812xl4.jpg
Also, any tehnique to make it look “less” ugly? It looks kind of ugly …

Okay, try these techniques. First, select everything in edit mode and hit W >> Remove Doubles. If that doesn’t help, go the the edit buttons (F9) and put on “Auto Smooth” And also add an edge split modifier but don’t apply it if you want to make changes. try rendering to see if that took care of it. Oh, and try selecting everything in Edit Mode and hit Ctrl+N. Hopefully one of those will work. Good luck!

ao would make it look better…

Looking at your screenshot, it looks like there’s an error from the renderer trying to smoothly shade over edges that are too sharp. Essentially, set smooth tries to smooth the shading over faces to prevent them from looking faceted. If the angle is too sharp, it produces incorrect and illogical results.

The primary tools we have to fix this are (as mentioned above) the Autosmooth button and the EdgeSplit modifier. I’d personally recommend the EdgeSplit, since the results are immediately visible in the viewport, and it offers more control to you as an artist.

http://wiki.blender.org/index.php/Manual/Mesh_Smoothing

Cheers, and good luck!