protected Material getMaterial() {
        if (mat == null) {
            mat = new Material(assetManager, getMaterialDefPath());
            initDefaultMatParams(mat);
        }
        return mat;
    }
Initializes material parameters to their default settings.

@param material
jme3-plugins/src/gltf/java/com/jme3/scene/plugins/gltf/MaterialAdapter.java