highly detailed 3D model of a double cheeseburger. The model should showcase two juicy beef patties stacked with melted cheddar cheese in between and on top. Include crisp lettuce, fresh tomato slices, and onion rings, with a smear of sauce on the inside of a sesame-seed bun. The burger should look mouthwatering with the cheese oozing slightly, and the colors vibrant, reflecting the textures of fresh ingredients.