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[Mathias 'cylab' Henze]

Just for a test, replace the content of the .obj file with the following:

Code:

v 0.0 0.0 0.0
v 10.0 0.0 0.0
v 0.0 0.0 10.0
f 1 2 3
v 10.0 0.0 10.0
v 0.0 0.0 10.0
v 10.0 0.0 0.0
f 4 5 6

[Marvin Fröhlich]

Should i triangulate the shapes to avoid this phenomenon? If yes, how to do that?

Yes, the OBJLoader only supports triangulated models. In blender you just press something like CTRL+T or so.

Marvin

['n ddrylliog]

Marvin : I think I have already seen Ludo's problem somewhere.. Xith3D maybe has a problem with lighting, that should be investigated further.

[Mathias 'cylab' Henze]

Tried the changed content I posted above? I changed the vertex order to be counterclockwise for both triangles. In the original .obj-file it the first was counterclockwise and the second clockwise. If opengl automatically generates normals, they would point in opposite directions if the vertex order is not the same for both triangles.

[Marvin Fröhlich]

Hmm... lighting worked perfectly in the last months. I really believe, it's something about the model.

Marvin

[Ludovic Marcé]

Tried the changed content I posted above? I changed the vertex order to be counterclockwise for both triangles. In the original .obj-file it the first was counterclockwise and the second clockwise. If opengl automatically generates normals, they would point in opposite directions if the vertex order is not the same for both triangles.

Yes, thanks, this was the trick.
Now, my converter creates the obj files like that:

MNTbis.obj (DEM)

Code:

v 0.0 0.0 10.0
v 5.0 0.0 20.0
v 40.0 5.0 20.0
f 1 2 3
v 0.0 0.0 10.0
v 30.0 10.0 20.0
v 40.0 5.0 20.0
f 6 5 4
v 0.0 0.0 10.0
v 30.0 10.0 20.0
v 25.0 15.0 20.0
f 7 8 9
...

It's better but still not perfect as you can see on the screenshots.
I've still few black triangles, I don't know why.
It's probably the obj i create that is not good.

[Marvin Fröhlich]

You could try to use the NormalsVisualizer on the model's shapes. Then you'll see, if the normals are as expected.

Marvin

[Mathias 'cylab' Henze]

try to find an .obj-exporter that also exports normals.

['n ddrylliog]

>> try to find an .obj-exporter that also exports normals.

I think he creates the obj files on the fly, from another file format he have to loads from (data comes from the IGN, "Geographic National Institute" in France).