turn off mesh disappearing while zooming?

Something I’m finding very annoying - the surface of the mesh now disappears when you zoom in while in perspective mode in Blender 2.70. (I know it always has, because you in effect went “inside” the mesh, but now it seems that it disappears as soon as you get close to the surface…) Is there a way to “turn off” this function?

Reason I ask…I was trying to select specific edges of a mesh in order generate a UV layout with just those edges showing, so I could export it into GIMP to create a texture where just those edges showed paint worn away to copper underneath. I need to get very close in order to select the right edges, because they’re very slender.

I must have spent half an hour trying to select just the edges I wanted in both wireframe and solid mode, and getting increasingly frustrated with the mesh either disappearing, or having to try and click at a distance and grabbing the wrong thing…arrrghhh!!!

I finally just unwrapped the whole thing, and generated my UV layout from that. Now I have to go into GIMP and try and find just the edges I want in a larger layout to try and achieve the effect I want…

Sorry if this isn’t making much sense. After fighting with Blender and pulling my hair out (and I don’t have much as it is), my brain is frazzled. Any help or suggestions on what I can try would be appreciated.

Yes, switch from perspective to orthographic viewmode. The reason for it disappearing in perspective viewmode might be because you go through the mesh, or it’s a small object and surface is close enough to viewport clipping distance to kick in and occlude that geometry. Clipping setting is on the properties panel (N), with start and end values. Camera has clipping values too, which are in camera (object data) properties.

With numpad_period key it’s possible to quickly zoom in to selection.