QUESTION Blender causing Interior to be messed up?

So I've been trying to fix a few small details on some modded cars and while the process itself didn't seem too bad, when I eventually finally managed to save it as kn5 I noticed that the interior was all messed up

I tried converting the extracted .fbx into .kn5 (using kseditor) and it came out fine. Then I tried importing the .fbx into Blender, without doing anything immediately export it and try converting that file to .kn5 and that's when I noticed the issue happening. So I know it's not an issue with what I edited, but rather some setting in Blender that is potentially ruining it?

I even tried it with an RSS car just to be assured it's not the mods fault and I noticed the same things

1st attachment is the Blender export, 2nd attachment is what it should be like

 

there is a long and painfull story about blender and amd graphics cards, try another blender or gfx-driver version, or just ignore wrong transparency in material preview in 3d viewport

 

ok, something is messing up the Normals, what you see as holes will be visible from the other side, but I'd guess its rather whatever you use to convert the kn5 to fbx that causes this. You need to manually active Backface culling to see these "holes" in Blender

There were recent issues with AMD cards (I'm on one too), but these were fixed in the later releases.

 

oh you were right, activating backface culling did reveal the holes. I take it it's just a matter of recalculating normals then?

I used CM to export the kn5 to fbx. Weirdly enough if I straight away open that fbx in kseditor and save it as a new kn5 it comes out perfectly fine, seems to be only when I import it in Blender (or 3dsmax for that matter) that causes the issue

 

that's odd, tho it may be due to something inside the fbx assembly that AC and its editor ignore, but Blender/Max don't (for example the very first mod track Joux Plane works perfectly fine in AC still, but all the unpacker tools can't make heads or tails of it, as it was encrypted by Kegetys with a "handmade" script. Could just be a ; or ] at the wrong spot).