Hi Arno:
Sorry, but this was discussed in other threads, and is likely best not pursued further in this particular thread.
[
EDITED]
Detailed explanations of "
retopology" in 3D models, implications of retention during import / export via MCX, and run time rendering by FS are cited here:
https://www.fsdeveloper.com/forum/threads/do-unseen-polygons-affect-fps.453844/post-892376
[
END_EDIT]
IIUC, questions (1+2) above pertain to derived 3D surfaces using the Sketchup "
Smooth Coplanar" feature.
https://help.sketchup.com/en/sketchup/softening-smoothing-and-hiding-geometry
AFAIK, those derived 3D surfaces actually are imported / retained in 3D models by MCX.
However, the 'Flickering' surfaces issue above, is not a result of (only) the Sketchup "
Smooth Coplanar" feature.
'Flickering' of derived surfaces pertains to derived Triangulated surfaces using the Sketchup plugin:
"
TIG: Import OBJ with Textures"
https://sketchucation.com/pluginstore?pln=obj_importer
I have discovered that plugin mistakenly reverses Textures on many imported, Triangulated
*.OBJ surfaces
AFAIK, the anomalies I previously saw was a result of aircraft MDLs imported by MCX, exported as
*.OBJ with PNG Textures, then being imported to Sketchup via "
TIG: Import OBJ with Textures" plugin.
That plugin apparently was mistakenly reversing Material orientation of many (but not all) Triangulated derived surfaces.
IIRC, both sets of surfaces were visible in the 3D model in Sketchup after exported by MCX and imported to Sketchup.
PS: I did not see the same result if I imported the aircraft using ASSIMP-based "
Samuel T: Universal Importer" plugin
https://sketchucation.com/pluginstore?pln=universal_importer
But, via that plugin, the same aircraft
*.OBJ 3D model displays in Sketchup with transparent Material attributes on exterior surfaces.
GaryGB