In a three-dimensional printing method example, a liquid functional agent is selectively applied. The liquid functional agent includes i) an energy source material or ii) an energy sink material. A metallic or ceramic build material is applied. The liquid functional agent is selectively applied any of before the metallic or ceramic build material, after the metallic or ceramic build material, or both before and after the metallic or ceramic build material. The liquid functional agent patterns the metallic or ceramic build material to form a composite layer. At least some of the metallic or ceramic build material is exposed to energy. A reaction involving i) the energy source material or ii) the energy sink material is initiated to alter a thermal condition of the composite layer.