Abstract: In one example a method of generating a three-dimensional object in a 3D printing system using a fusing agent of a first colour and a build material having a second colour different from the first colour, and a detailing agent, comprises obtaining object model data describing an object to be generated, and determining a first portion of the object to be generated to have the second colour. The method comprises determining object generation instructions to generate the object by defining a gap region of a layer of build material that is to correspond to the first portion of the object to have the second colour on which no agents are to be applied, a band of detailing agent on a layer of build material immediately adjacent to the gap region to define an outer limit of the gap region and therefore a boundary of the first portion of the object, and a fusing agent region on a layer of build material adjacent to the gap region on which fusing agent is to be applied.

Abstract: A system includes a controller to receive data corresponding to an object or slices of the object to be generated by a 3D printer, wherein the 3D printer includes an array of printhead nozzles to selectively eject a print agent on a layer of build material in a build chamber having a build chamber wall, the array of printhead nozzles spanning substantially the full width of the build chamber and moveable along a length of the build chamber. The controller to generate first print data used to generate layers of the object based on the received object data, and to generate second print data used to generate layers of a sacrificial barrier located between the object and the build chamber wall, the second print data is generated such that different parts of the sacrificial barrier are generated using a different plurality of nozzles of the array of printhead nozzles.

Abstract: Object model data defining a plurality of objects to be built by a three-dimensional printing apparatus is obtained. The plurality of objects to be built are arranged in a configuration to be printed with objects having a first property arranged in a first separable region of a build volume and objects having a second property arranged in a second separable region of the build volume. Print data defining the configuration of the plurality of objects to be built is generated.

Abstract: In an example, a method includes receiving, by at least one processor, object model data, the object model data describing at least part of an object to be generated in additive manufacturing. Pattern data is also received, wherein the pattern data describes a pattern of variable opacity intended to be formed internally to the object. Object generation instructions for generating an intermediate layer of the object comprising the pattern of variable opacity may be determined by at least one processor.

Abstract: A method of configuring an additive manufacturing system. The method comprises configuring the additive manufacturing system with a first value of an operation parameter associated with the additive manufacturing system and, with the additive manufacturing system configured with the first value of the operation parameter, forming, in a build chamber, a first object The additive manufacturing system is subsequently configured with a second value of the operation parameter and, with the additive manufacturing system configured with the second value of the operation parameter, a second object is formed in the build chamber, subsequently to forming the first object. The method further includes receiving a signal indicative of which of the first value or the second value the operation parameter is to be configured with for subsequent operation of the additive manufacturing system.

Abstract: A method includes receiving an object model describing a geometry of a three-dimensional, 3D, object for printing by a 3D printer, and build material data indicating a selected build material to be used in printing the 3D object by the 3D printer. A volume to surface area ratio of the object model is calculated. In response to the volume to surface area ratio being greater than a first predetermined threshold value for the selected build material, it is determined that printing the 3D object by the 3D printer from the selected build material is expected to result in a defect in the 3D object.

Abstract: A 3D printer is controlled to apply a print agent at a plurality of predetermined locations in a build chamber of the 3D printer, and energy is applied to heat the build chamber. A thermal image of the build chamber is received. Based on the thermal image, an error in application of the print agent in the build chamber is determined.

Abstract: There are disclosed methods and devices for build temperature control. In some examples, a method comprises applying a temperature controllable top cover over a top of the build volume. The method may further comprise controlling the temperature controllable top cover to maintain a temperature substantially equal to a build temperature for a predetermined period of time. The method may further comprise applying a thermally conductive bottom cover to a bottom of the build volume.

Abstract: Printer control data is generated which includes a three dimensional model for a protective structure to be built around a printed object by a three-dimensional printing apparatus, which protective structure is configured to compensate for the distorting effects of uneven shrinkage during cooling. The three dimensional model for the protective structure comprises a plurality of side panels and at least one extensible member interconnecting two or more of the side panels, which extensible member is configured to be extensible in response to shrinkage of the plurality of side panels during cooling. A method and apparatus is disclosed which obtains object model data defining an object to be built by a three-dimensional printing apparatus and automatically generates a three dimensional model for a suitable protective structure that has extensibility as an integral feature of the design to compensate for uneven shrinkage.

Abstract: Disclosed are systems, control mechanisms and methods that apply different printer control fluid parameters when forming internal and external features of a three-dimensional object within an additive manufacturing system. The identification of internal and external features may involve analysing an object model, comprising data describing the object to be manufactured, to identify all edges of a three-dimensional object and determining which of the edges are internal edges and which are external edges of the object. A control fluid strategy can be optimised for different object feature types, to improve mechanical properties of the final object and/or reduce usage of detailing agent.

Abstract: In one example a method of additive manufacturing includes obtaining object model data and colour data. The object model data describes at least portion of an object to be generated in additive manufacturing using a build material having a first colour and a fusing agent having a second colour different from the first colour. The colour data describes an intended colour of at least portion of the object to be manufactured by additive manufacturing. The intended colour is substantially the first colour, the second colour or a colour therebetween. The method includes determining object generation instructions to apply the fusing agent to a first region of a layer of the build material. The first region of the layer corresponds to portion of the object and the instructions are to apply fusing agent at a contone level such that the colour of the portion of the object corresponding to the first region of the layer of build material is substantially the same as the intended colour as described by the colour data.

Abstract: A non-transitory machine-readable storage medium is encoded with instructions executable by a processor. The machine-readable storage medium includes instructions to modify data representing a three-dimensional object model, the three-dimensional object model for use in generating a three-dimensional object in a build chamber. The data is modified to include a container to substantially encapsulate contents of the build chamber comprising the three-dimensional object and non-solidified build material. A wall of the container comprises heat transfer control elements to control dissipation of heat from the contents of the container.

Abstract: In certain examples, a method comprises determining a fusing area density distribution of a build layer from build data relating to a build layer of a three-dimensional model to be printed by an additive manufacturing system. The method comprises, in response to a determination that a region of the build layer has a fusing area density outside of a fusing area density tolerance window, modifying the build layer to define a build layer in which the region has a fusing area density that is within the fusing area density tolerance window.

Abstract: A method is disclosed. The method may comprise obtaining, using a processor, design data representing an object to be generated in a fabrication chamber of an additive manufacturing apparatus. The method may further comprise determining, based on the design data, that a part of the object is to be generated within a predefined portion of the fabrication chamber. The method may further comprise responsive to said determining, generating, using a processor, data representing an ancillary element to be generated in the predefined portion between the part of the object and a wall of the fabrication chamber. An apparatus and a machine-readable medium are also disclosed.

Abstract: Examples relate to a 3D printing and a method comprising receiving a packing ratio of an object to be printed; based on the received packing ratio, determining a mixing ratio of fresh to recycled build material to use for printing the object; and providing the mixing ratio to a dispenser to dispense fresh and recycled build material in the provided mixing ratio for printing the object.

Abstract: In one example, an apparatus comprising a controller to instruct a build platform to support a plurality of layers of build material in a build zone, wherein the build platform is moveable during a build of a three-dimensional object to change the size of the build zone, wherein the controller is to determine respective displacements of the build platform to successively receive each of the plurality of layers of build material in the build zone during the build, wherein at least one of the respective displacements is based on data determined from a three-dimensional object obtained in a previous build.

Abstract: A mobile build unit (2) for selectively locating in a build chamber (4) of an additive manufacturing machine (6). The mobile build unit has a build platform (8) to receive build material; and a build unit heater (10) to heat layers of build volume formed on the build platform (8). The build unit heater (10) is movable between a first position in which the build unit heater (10) is stored, and a second position in which the build unit heater (10) is mounted over the build platform (8).

Abstract: An example method of generating three-dimensional objects is disclosed. Object generation instructions to generate the object may be determined by defining a shell region of a layer of build material corresponding to the first portion of the object having a first color, and defining a fusing agent region on a layer of build material adjacent to the shell region on which fusing agent of a second color is to be applied and specifying an amount of colorant to be applied to the shell region wherein the object generation instructions specify application of fusing agent and colorant such that, when the layer of build material is heated using a heat source, the fusing agent region of the build material melts due to energy absorbed from the heat source and the build material of the shell region melts due, at least in part, to energy transfer from the fusing agent region.

Abstract: In accordance with the disclosure, there is provided, a method. The method may comprise performing a printing operation to produce a part based on a predetermined fluid strategy. The method may further comprise assessing part data, related to the printed part, for any inaccuracies, based on a printing operation input. The method may further comprise adapting the fluid strategy for a next printing operation, based on any identified inaccuracies.

Abstract: Example implementations relate to controlling the application of layers of build material in 3D printing. One example implementation determines a temperature at a predetermined location of a layer of build material following fusing according to an object model, where the predetermined location is dependent on the object model. The application of a new layer of build material is controlled dependent on the determined temperature.