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: In some examples, a system receives measurement data from measurements of first three-dimensional (3D) parts formed on a build bed of an additive manufacturing machine with different contone levels of a liquid agent, and determines, based on the measurement data, geometrical deviations of the first 3D parts from a baseline geometrical property. The system generates, based on the determined geometrical deviations, a model that correlates contone levels of the liquid agent to corresponding geometrical deviations, the model for use in an adjustment of the liquid agent based on a contone level adjustment to compensate for a geometrical deviation when building second 3D parts with the additive manufacturing machine or another additive manufacturing machine.

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: In an example, a method includes identifying, by processing circuitry, a feature of less than a threshold size of an object to be generated in additive manufacturing. In some examples the method further includes determining, by processing circuitry, a first density of a print agent to be applied to build material when generating the identified feature of the object based on an intended flexibility of the feature of the object. The method may further include determining, by processing circuitry, a second density of print agent to be applied to build material when generating another feature of the object.

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 computing device comprising a controller is disclosed herein. The controller is to receive an arrangement of a 3D object a virtual build volume to be generated by a 3D printer; determine an indication of the expected warpage of a portion of the 3D object; and modify the virtual build volume to add at least one anchor structure connected to the portion of the 3D object if the expected warpage is above a predeterminable threshold.

Abstract: According to an example, a method of processing a print job in an additive manufacturing system comprises: applying a geometrical calibration to the print job to obtain a calibrated job; determining a height of a set of print job powder layers to be formed to generate the objects based on the calibrated print job; determining a height of a set of warming powder layers to be formed prior to the set of print job powder layers; determining an ideal height of a set of annealing powder layers to be formed after to the set of print job powder layers; and determining if the combined height of the sets of layers exceeds the maximum available height.

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: Disclosed is a method that determines information associated with at least a portion of a build volume that comprises one or more 3D printed objects, and determines an amount of material to be applied to the build volume for use in annealing the one or more 3D printed objects of the build volume, on the basis of the information.

Abstract: In an example, a method includes obtaining a compensation model characterising a relationship between a location of an object within a fabrication chamber of an additive manufacturing apparatus and a geometrical compensation to be applied to a model of said object, wherein different geometrical compensation values are associated with different locations. In some examples the method further includes determining a magnitude of a dimension parameter of each object of a set of objects to be generated in a build operation. The method may include determining a spatial arrangement of objects to be generated within the build volume, based on the magnitude of the dimension parameters and the geometrical compensation values for an intended location of object generation in the spatial arrangement.

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: In some examples, a system receives information that represents a value of a physical property of a three-dimensional (3D) object as a function of a location of the 3D object built by an additive manufacturing machine. The system generates, based on the received information, a map that includes adjustment values corresponding to different locations of a layer of build material, the adjustment values when applied by the additive manufacturing machine to modify data representing a further 3D object to be built by the additive manufacturing machine.

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 computer-implemented method is disclosed. The computer-implemented method comprises receiving data indicative of a post-manufacture treatment to be applied to a three-dimensional object following completion of a manufacturing process to generate the three-dimensional object; and determining, based on the received data indicative of the post-manufacture treatment, build parameters to be applied in respect of the manufacturing process. A manufacturing apparatus and a machine-readable medium are also disclosed.

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: Certain examples relate to generating output print data representing at least one object. Output print data is generated by performing a geometric transformation on a part of object model data representing the identified region. The object model data represents the at least one object to be printed. The geometric transformation may use a transformation parameter which is determined based at least on the object model data and object property data. The object property data identifies a region of the at least one object and associates it with a selected physical property.