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: 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: Described is an apparatus, a method and a 3D printer to: based on a first representation representing a 3D object to be printed using a build material, the object comprising a body having a surface area and a volume, determine a parameter representing a relationship between the surface area and the volume of the body; determine a scaling factor using the determined parameter; and generate a second representation representing the 3D object in which the 3D object is scaled according to the scaling factor.

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.

Abstract: In an example, a method includes receiving, at least one processor, object model data representing at least a portion of a first object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber. An indication of an amount of fused build material in a region of the fabrication chamber which is to be below the region in which the first object is to be generated may be determined and a dimensional compensation value to apply to the object model data representing the first object may be determined based on the determined indication. The determined dimensional compensation value may be applied to the object model data to derive modified object model data.

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: In an example, a method includes receiving, at least one processor, voxelised object model data describing at least part of an intended fabrication chamber content to be generated using additive manufacturing. The voxelised object model data may be derived from a first data set modelling a first object as 2D slices and a second data set modelling a second object as a 3D mesh. Data within the voxelised object model data which is derived from the first data set may be identified, and a geometrical transformation may be applied thereto.

Abstract: In an example, a method includes receiving, by at least one processor, object model data describing a first object to be generated in additive manufacturing and an intended object generation location of the first object, wherein the intended object generation location is a relative location within a generic fabrication chamber. The method may further comprise determining, by at least one processor, a location for generation of the first object in a first fabrication chamber, wherein the first fabrication chamber is an intended fabrication chamber of object generation. The location may be an absolute location in the first fabrication chamber which corresponds to the relative location within the generic fabrication chamber.

Abstract: In an example, a method includes receiving, by at least one processor, object model data representing at least a portion of a first object that is to be generated by an additive manufacturing apparatus. An indication of a proportion of the first object which is solid may be determined, and, based thereon, a dimensional compensation value may be determined. The determined dimensional compensation value may be applied to the object model data to determine modified object model data.

Abstract: In an example, a method includes obtaining an indication of a deviation from an expected dimension of at least one dimension of an object generated using an additive manufacturing apparatus. A geometrical compensation model to apply to object model data for generating objects using additive manufacturing to compensate for anticipated deviations in dimensions may be determined from the obtained indication. The geometrical compensation model may comprise a first value to apply to object model data to modify a specification of an external dimension; and a second, different, value to apply to object model data to modify a specification of an internal dimension.

Abstract: An example method includes obtaining, by at least one processor, a plurality of categorised indications of deviations from expected dimensions for at least one object generated using an additive manufacturing apparatus wherein the categories comprise at least two of a first dimension type comprising dimensions which are expected to increase on application of a positive offset to object model data used to generate an object, a second dimension type comprising dimensions which are expected to decrease on application of a positive offset to the object to object model data used to generate an object, and a third dimension type comprising dimensions which are expected to be unaffected by application of an offset to object model data used to generate an object. The method may include determining a geometrical compensation model to apply to object model data for generating objects using additive manufacturing to compensate for anticipated deviations in dimensions.

Abstract: A method is described in which data representing a plurality of three-dimensional objects to be printed in a printing job is received and printer control data is generated based on an attribute to be prioritised for each object. The plurality of three-dimensional objects are printed in one printing job by printing a plurality of successive layers based on the generated printer control data. Printing a layer comprising printing a portion of a first object in a first print mode, wherein a first attribute is prioritised, and printing a portion of a second object in a second print mode, wherein a second attribute is prioritised.

Abstract: In an example, a machine-readable medium stores instructions which, when executed by a processor, cause the processor to: update a 3D printing geometrical compensation model with at least one correction determined using a combination of a dimensional correction determined from measurements of objects generated using a first geometrical compensation and a dimensional correction determined from measurements of objects generated using a modified version of the first geometrical compensation.

Abstract: In an example, a method may include obtaining a first measurement of a first object generated using additive manufacturing apparatus based on object model data and obtaining a second measurement of a second object generated using the additive manufacturing apparatus based on object model data to which a first geometrical compensation parameter has been applied. An effect of the first geometrical compensation parameter may be determined based on the first and second measurements and, based on the determined effect, the first geometrical compensation parameter may be evaluated.

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 obtain input print data comprising property data identifies a region of the at least one object and associates it with a selected physical property.

Abstract: In an example, a machine-readable medium stores instructions which, when executed by a processor may cause the processor to modify data for characterising geometrical modifications for use by each of a plurality of additive manufacturing apparatus, wherein a modification for a particular additive manufacturing apparatus is based on dimensions of objects generated by that apparatus.

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.