A realistic 3D model of a burger, featuring a slightly toasted sesame seed bun with visible texture and subtle browning. The patty is thick, juicy, and has a charred surface with grill marks, layered with melted cheese, crisp lettuce, fresh tomato slices, and onions. Condiments like ketchup and mustard are visibly oozing from the sides, adding to the appetizing appeal. The materials should reflect the different textures: the softness of the bun, the roughness of the patty, and the smoothness of the cheese and condiments.