the reason for the extra edges and the disappearing faces when deleting edges is that blender doesn't support ngons. so you have to model a bit differently and put more thought into your actions beforehand. i don't find it to be a big problem for non-organic models but for doing characters and such things i miss ngons a lot. that's why i also use modo besides blender.

hm... i don't have the problem with the blender directory. the file dialog always seems to use the directory i last was in but what i don't like about it is that it seems to be quite random in what window it opens.

i also don't have problems with import. most import scripts work great. was there something special about that model?

what do you mean? of course blender supports quads. it even supports fake ngons (hidden edges) but they aren't very useful. the obj exporter also support normals.

But a quad is a N-Gon, isn't it?

Blender 2.45. I can see that there is a check field for normals in the OBJ exporter. But no matter if i check it or not the result exports without normals. Unfortunately.

yes, a quad and a triangle are ngons too but the n stands for an arbitrary number of edges and blender only supports 3 and 4 at the moment.

what application do you use to load the obj? truespace? even if there are no normals there shouldn't be a problem since they usually get recalculated anyway.

Ah, this has nothing to do with what app i load the file then. It's the OBJ file that Blender writes where the normals are missing. Do a test, export then open such a file and have a look for vn above the f part. vn are the normals, f the faces index. You will find none. Or even look at the f lines. With normals it should be three numbers and two slashes. Like 1/2/1. Without normals it is two numbers and one slash.

Blender doesn't write the normals. At least here they do not make it in the file.

strange. i get normals:

# Blender3D v245 OBJ File:
# www.blender3d.org
mtllib cube.mtl
o Cube
v 1.000000 -1.000000 -1.000000
v 1.000000 -1.000000 1.000000
v -1.000000 -1.000000 1.000000
v -1.000000 -1.000000 -1.000000
v 1.000000 1.000000 -1.000000
v 0.999999 1.000000 1.000001
v -1.000000 1.000000 1.000000
v -1.000000 1.000000 -1.000000
vn 0.000000 -1.000000 0.000000
vn 0.000000 1.000000 0.000000
vn 1.000000 0.000000 0.000000
vn 0.000000 0.000000 1.000000
vn -1.000000 0.000000 0.000000
vn 0.000000 0.000000 -1.000000
usemtl Material
s off
f 1//1 2//1 3//1 4//1
f 5//2 8//2 7//2 6//2
f 1//3 5//3 6//3 2//3
f 2//4 6//4 7//4 3//4
f 3//5 7//5 8//5 4//5
f 5//6 1//6 4//6 8//6

but even without normals an obj should load and display correctly in other software. normals can get recalculated and most software will do this correctly.

That is really curious.

EDIT: testing testing testing ... ah that's not fair. I have to turn Normals OFF to write the normals. Or wait, greyed is activated? Blender and its GUI ...

if it is darker the button is pressed (pressed = on!). does it work now?

Yup, now it works

When pressing a button it normally becomes lighter and activated. Deactivating turns normally the light out. So no wonder i had my problems here.