mesh issue from a beginner

I cannot really understand where and what I’m doing wrong, somebody can help please, pic attached. the left side of the house is fine but the right one is just not what i want, this glossy effect that I don’t have set anywhere, what am I missing?

thanks a lot

What you are seeing there is the smooth shading effect: blender tries to “smooth” the surface on its edges and vertices - what looks weird if the surface is flat.
To disable smoothing, select the wall object and press “flat” in the left Toolshelf:

It’s likely smooth shading that goes over high angle edges. Smooth shading is used to hide edges on non-flat surfaces but needs to be cut on high angle edges, or disabled on flat surfaces. Auto smooth setting is usually used to cut the shading on edges over the set angle, or on edges that are marked as sharp.

Most important thing you’re missing in your post is an example .blend of the problem so it can be used to troubleshoot and produce visuals when replying. Apart from that you’re missing the rest of the interface from the screenshot with all its information.

  • next time also show wires (wire frame)
  • know about topology (in your case: can be fixed by adding couple of edge loops)

is advanced but provides info on what to take care to prevent such ‘pinching’ :wink: