QUESTION The structures (mesh) bug once sent to kseditor

[Tino14]

Hello, I have a big problem that is driving me crazy.
I take 652 steps forward to go back 652 steps.
I made my mesh without too much trouble I model the map with elements already present which work well, all are correct.
Then when I duplicate a mesh or I don't know too much about it because I do a lot of things at the same time but I have the impression that it's all the meshes disappear kseditor doesn't even see them whereas on blender everything is Good.
The material textures them and everything that goes with them and necessarily functional since I duplicate it from something that works but no, so I find myself doing something for 6 hours to finally arrive and see that half of the textures are no longer there. I have holes everywhere a real building site.
If anyone knows where it can come from, I'm sending below the blender rendering and the rendering I get with Kseditor..

 

[Rob Pawn]

when you copy things and mirror them (i guess u did it to the platform building) faces got flipped.
in blender you can activate "FACE ORIENTATION" --- red ones are transparent and blue ones you see...

so important is to "apply scale" and flip the faces and your problem will be fixed...

 

[Tino14]

I found my problem which will be quite complicated to explain.
I tried to search for a while at the same time to start all over again what I had done.
By making the connection to the curves for a road or other, I modify the axis of my object to frame it as it should and after multiple attempts to modify the axis of its object in a curve makes the meshes bugger in Kseditor.
To see now if when it is not linked to anything, does it still cause a problem, I test it

 

[Tino14]

Where do you see the face orientation?

 

[Rob Pawn]

 

[Tino14]

Yes it's good I found it thank you very much.
However I still have textures (mesh) which do not appear but I think it is due to the duplication using the axes and not the rotation

 

[fughettaboutit]

cant hurt to do this: (you can do with all selected)
Ctrl+A ->

and then this:

and check that one mesh has only one material, or results may vary:

 

[Tino14]

Everything worked I forgot to answer a big thank you to you