another flipped normals problem

Despite normals are shown faced outside correctly in 3D view, sometimes specific normals are exported flip. This nuisance occurs in some objects.

The problem could be fix if you try this.
1. Select the object in 3D view.
2. Object > Clear/Apply > Apply Scale/Rotation to ObData (in Object Mode).
3. With Ctrl + N, fix normals again.

These kind of situations are happen when I rotate, scale, transform an object a lot.

fix exported vertex normals (on Blender 2.49)

While surface normals show vertical to face correctly in 3D view, the blender .obj exporter sometimes uses another normal data. The normal data seem to not surface normals but vertex normals.

To fix them, in 3D view select the face exported with unwilling normal data and run command Mesh > Faces > Set solid. After setting faces solid, the exporter would not use vertex normals.