A forming tool is used, which has a tool trough arranged in a stationary manner and a pressure bell, which can be lowered onto and lifted away from the tool trough. An arrangement is created in which a single- or multi-layer, initially flat, flexible laminate separates the trough interior from the pressure-bell interior in a pressure tight manner. A table, on which the 3-D substrate to be coated is located, assumes a lowered position within the trough interior; there is a considerable, free intermediate space (between the laminate and the 3-D substrate. A radiant-heater assembly is inserted into said intermediate space. The radiant-heater assembly has a carrier, on the top side of which radiant heaters that can be activated are attached and on the bottom side of which radiant heaters that can be activated are attached.