omg I have to many nonmanifold edges

There are a bit too many nonmanifold edges in my model. I am talking about the selected ones around the rounded hole (not the ones that are the rounded hole and not the ones at the bottom). How can I make them manifold again?

http://img515.imageshack.us/img515/4805/nonmanifoldap1.th.jpg

Try selecting all vertices, w -> remove doubles. That might remove most of them.

nope, nothing changes. Idid some reading and it seems that nonmanifold edges are edges with less or more than two adjacent edges. Wich is the case for most of the edges in question. And I guess I cant do anything about since thats how the model is designed. e.g. the big rectangle edges that are selected here have 3 adjacent faces. Is it bad to have nonemanifold edges in the model after all? Note that I need to stay as lowpoly as possible.

Non-manifold edges are edges that border holes or openings in your mesh. If there are supposed to be holes or openings in the mesh, they are not a problem at all. The “Select Non-Manifold” option simply shows you where the openings are, so you can make sure all the openings are where you want them to be and you can close any openings you accidentally left open.

How did you select the edges (ctrl-alt-shift-m?)?

@Orinoco

I think you are wrong. Non-manifold edges are also edges that have more than 2 adjacent faces. Wich would not qualifly as a “hole”. Try to loopcut a simple plane and extrude the middle edge upward. The original edge you extruded from has become a nonmanifold edge …

@BeBraw

Yes

Ok, but my point is they can be either deliberate or accidental. If deliberate, not a problem.

I guess in may case (look at the selected faces in my model in the intial post) the are deliberable and probably not a problem. Do you agree ?