Does selecting high texture setting ( not very high, or extreme) effect 3-D VC especially add-on aircraft like Jar Design a320 or FF 777, FF 757?!

It depends on how the plane was authored.  If the author opted for the objects in question to be protected from resolution degradation, then you should always see those objects at 100% resolution.  An easy way to test this is, to set the sim's texture resolution to minimum, and reload the plane.  

 

Exterior textures should now look blurry, and maybe some interior textures as well… but if the plane was authored taking these X-Plane optimizations into account, you should see the interior textures that need to remain legible at 100% resolution.

It depends on how the plane was authored.  If the author opted for the objects in question to be protected from resolution degradation, then you should always see those objects at 100% resolution.  An easy way to test this is, to set the sim's texture resolution to minimum, and reload the plane.  

 

Exterior textures should now look blurry, and maybe some interior textures as well… but if the plane was authored taking these X-Plane optimizations into account, you should see the interior textures that need to remain legible at 100% resolution.

thank you

I've seen this happen on some of Carenado's planes when reducing the texture resolution, particularly the Bonanzas. Once lowered, it's often hard to make out the detail. I don't remember if it happened in the 777 as I don't have it installed, but I remember it was quite usable on "very high" with texture compression enabled.

I've seen this happen on some of Carenado's planes when reducing the texture resolution, particularly the Bonanzas. Once lowered, it's often hard to make out the detail. I don't remember if it happened in the 777 as I don't have it installed, but I remember it was quite usable on "very high" with texture compression enabled.

thanks...