Hi there!
Sometimes I use same texture in my models but I didn’t figured yet what decide in 3D model that I need use Flip texture parameter in material. The question is - if I see in me new 3d model that need flip parameter how can I translate UV in blender to avoid this. What Flip exactly do?
you can search forum here, there were topics 
in code:
assetManager.loadTexture(new TextureKey(path, flipValue))
flip invert Texture coords, But generally loaders make auto-flip, so idk why you need that.
For example Blender UV is flipped, it means bottom should be top pixel, so need flip it.
except code line, it can be done in material itself.
But again, how do you load model? because you should not have issue with that. My Blender->GLTF->JME exports are 1:1 with that.
Technically, it’s inverting the image to match flipped texture coordinates.
loadTexture with a flip=true texture key means the image would be upside down from one that isn’t flipped. That’s all.
Thanks guys!
Yep, that’s what I needed. Flip exactly “Mirror Y” to do in blender to “undo” changes made by importer. I use SDK 3.0 and “Convert to j3o” option.
The problem is when I first create model for one texture and reuse this tex in another model. Mostly when use Substance Painter. When I load material - in one is good and other is not. Strange but the easiest way is reimport with mirrored (flipped) tex or make second material with flip option set opposite. But I don’t know that second material with same textures have impact on performance.