Often when transferring models from Blender to something like JME, the textures will be upside down. Where you load the texture:
barrelMat.setTexture(“DiffuseMap”,
assetManager.loadTexture(“models/barrel/Barrel.jpg”));
Instead use the TextureKey form of the loadTexture() method and pass yFlip false since true is the default.
assetManager.loadTexture(new TextureKey(“models/barrel/Barrel.jpg”, false));
That should fix your issue.
References:
loadTexture() : http://hub.jmonkeyengine.org/javadoc/com/jme3/asset/AssetManager.html#loadTexture(com.jme3.asset.TextureKey)
TextureKey : http://hub.jmonkeyengine.org/javadoc/com/jme3/asset/TextureKey.html#TextureKey(java.lang.String,%20boolean)