Ok im using blender with the ogre exporter and i made a room for an FPS game, but when i am within the scene i have created, i can not see any of the vertices until i step out, i can see everything from outside. I found i could resolve this problem by, on blender, selecting everything then clicking e once to extrude, immidietly clicking away. This does mean that i can see the scene from within and outside, but it means there are twice as many vertices, this is supposed to be a very lowpoly game, and it is very hard to add more rooms and whatnot to this scene. Does anybody know how i can fixe this? thanks
your normals are probably facing the wrong direction.
Just to complement what kwando said, you can solve that by selecting all faces in edit mode, and pressing ctrl+n (recalculate the normals inside )or ctrl+shift+n (recalculate the normals outside).
thanks, what are the normals by the way?
A normal is a vector that is perpendicular to a plane. It is usually used to describe what direction a plane is ‘facing’. Normals can be used for a variety of things like calculating reflection vectors for lighting and possibly bullet bounces of of a surface.
there is a way to have normals on both sides of a polygon, can’t remember where someone posted this tho
@wezrule said:
there is a way to have normals on both sides of a polygon, can't remember where someone posted this tho
[java]
material.getAdditionalRenderState().setFaceCullMode(FaceCullMode.Off);
[/java]
:).
thats probably it 
@glaucomardano said:
[java]
material.getAdditionalRenderState().setFaceCullMode(FaceCullMode.Off);
[/java]
This won't flip the normals , it just renders the back faces of a mesh. So even with that you may have incorrect lighting from the inside.
If you want normals on both sides you have to double the faces with you modeling software, one pointing outside and one pointing inside.
So a solidify modifier would be a solution ok?
yes it would, but it creates additional faces for the edges. That’s a fast and easy solution though