Method and device for producing a three-dimensional object

A method for producing a three-dimensional object on a support by layer-wise applying and selectively solidifying a building material in powder form, the method comprising:

• lowering the support to a predetermined height below a working plane;
• applying an applied powder layer of the building material in powder form in the working plane over a build area located within the working plane by an application device moving over the working plane, wherein the application device includes a first elongated member extending across the build area and in use is spaced a defined height above the working plane to thereby spread powder building material on the build area to or below the defined height in a layer;
• selectively solidifying a respective applied powder layer at positions corresponding to a respective cross-section of the three-dimensional object to be produced;
• repeating the steps of lowering, applying and selectively solidifying during a build process until the three-dimensional object is completed;
• arranging a working table around the build area, the working table being at least partially located below the working plane;
• and
• providing a supply of powder building material in a container associated with the application device, and a powder metering device at a bottom of the container, wherein the metering device includes an elongated slot defined in the container and extending across the build area and opening above the application device, and an element that variably opens and closes the slot to provide a variable gap through which the powder building material is delivered to the application device in a controlled manner,
• wherein a quantity of applied building material in powder form is reduced or not deposited in at least a portion of one or more applied layers across an area of the working table in an actively controlled way to provide the portion with a reduced layer height, and
• wherein a maximum height of the applied layer is determined by a distance between a lower extremity of the first elongated member and a previously applied powder layer, the reduced height determined by actively controlling the amount of building material with the metering device to deposit the build material in a height less than the defined height at desired places across the working table during the build process.