An apparatus and method for generating a three-dimensional object. The apparatus includes a build material area, at least one agent distributor with a fluid reservoir to store fluid agent and at least one fluid ejection die to selectively eject fluid agent in the build material area. A cooling system to remove heat from the at least one fluid ejection die has a heat sink. The at least one fluid ejection die is in thermal contact with the heat sink via the fluid agent of the fluid reservoir.