Abstract: In an example, a method includes receiving, at at least one processor, object model data representing at least a portion of an object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber. At least one of a plurality of different geometrical compensation models to be applied to the object model data may be selected wherein the geometrical compensation models are to determine geometrical compensations to compensate for object deformation in additive manufacturing. An object generation operation based on a modification of the object model data using the or each selected geometrical compensation mode may be simulated and predicted attributes of the object when generated based on the or each simulation may be displayed. FIG.

Abstract: In an example, a method includes receiving object model data representing at least a portion of an object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber. At least one of a number of different geometrical compensation models to be applied to the object model data may be selected, where the geometrical compensation models are to determine geometrical compensations to compensate for object deformation in additive manufacturing. An object generation operation based on a modification of the object model data using the or each selected geometrical compensation mode may be simulated and predicted attributes of the object when generated based on the or each simulation may be displayed.

Abstract: In an example, a method includes receiving, at least one processor, object model data representing at least a portion of an object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber. An intended object placement location within the fabrication chamber may be determined, and a dimensional compensation to apply to the object model data may be determined using a mapping resource relating dimensional compensations to object placement locations. The determined dimensional compensation may be applied to the object model data to generate modified object model data using at least one processor.

Abstract: An example method includes obtaining a geometric compensation profile characterising a relationship between a location of an object within a first fabrication volume having a first depth of build material and a geometrical compensation to be applied to a model of said object. The method further includes determining that a first object is to be generated in a first build operation having a second fabrication volume which has a second depth. The method may further include determining a geometrical compensation to be applied to a model of the first object by: determining a first offset of the first object from the top of the second fabrication volume; identifying the geometrical compensation value associated with a location having the first offset from the top of the first fabrication volume; and determining the compensation to be applied to the model of the first object based on the identified geometrical compensation value.

Abstract: In an example, a method includes acquiring, by a processor and for a set of locations in a fabrication chamber for additive manufacturing, data identifying a first subset of locations associated with a first level of variability in deformations in object generation and a second subset of locations associated with a second, greater, level of variability in deformations object generation. A geometrical compensation model may be derived to compensate for anticipated deformations in object generation by a first additive manufacturing apparatus. The geometrical compensation model may comprise geometrical transformations to apply to object model data representing at least a portion of an object, wherein each geometrical transformation is associated with a location of the set of locations.

Abstract: In an example, a method includes receiving, at a processor, an object model describing a geometry of a three-dimensional object, and determining a transformed data model describing a volume containing a modified version of the three-dimensional object as a plurality of categorised contiguous, non-overlapping sub-volumes, wherein the modified version of the three-dimensional object includes a surface offset. Determining the transformed data model may comprises categorising the sub-volumes by defining a first region by determining an area swept by an offset operator when the offset operator is swept around a boundary of the sub-volume and defining a second region, interior to the first region, and indicative of the closest approach of the offset operator to the sub-volume when the offset operator is swept around the boundary. Intersections between a surface of the object model and at least one of the first and second region may be determined.

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: Certain examples described herein relate to generating a Neugebauer Primary area coverage (NPac) vector. In certain cases, an operating state of a printing system is determined. A first NPac vector is obtained, having an initial set of Neugebauer Primaries (NPs). The initial set of NPs comprise a NP that is not implementable with the operating state. A target set of NPs is determined on the basis of the operating state, the target set of NPs being implementable with the operating state. A second NPac vector is generated, the second NPac vector having the target set of NPs.

Abstract: Certain examples described herein relate to printer calibration. In some cases, adjustment data is received, indicating an adjustment to be applied to a given colorant. A Neugebauer Primary area coverage (NPac) vector defining an operating set of Neugebauer Primaries (NPs) is obtained. Configuration data is determined, dependent on the operating set of NPs. The configuration data maps colorant adjustments to relationships between NPs in the operating set, for both an increase and a decrease in the given colorant. In some cases, the configuration data and the adjustment parameters are used to identify first and second subsets of the operating set of NPs. The NPac vector is adjusted by decreasing an area coverage of an NP in the first subset and complementarily increasing an area coverage of an NP in the second subset.

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: 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: 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: In an example, a method includes receiving, at least one processor, object model data representing at least a portion of an object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber, wherein the object model data comprises a mesh model comprising data describing a surface of the object. A geometrical compensation vector may be determined for the object model data, the geometrical compensation vector having a first component applying to a first axis of the fabrication chamber and a second component applying to a second axis of the fabrication chamber. A geometrical compensation to apply to at least one location on the surface of the object may be determined by determining a product of the geometrical compensation vector and a vector indicative of the normal of the object surface at the location and the determined geometrical compensation may be applied to the object model data to generate modified object model data.

Abstract: Example implementations relate to compensating for shrinkage in 3D printing. One example implementation receives an object model to print a corresponding object in a three-dimensional (3D) printer, the object model having a plurality of surface coordinates. A plurality of dimensional modification compensation factors are determined dependent on respective locations within a printing volume of the 3D printer. The object model is adjusted at the plurality of surface coordinates using respective dimensional modification compensation factors depending on the location of the surface coordinates within the printing volume in order to generate a printable object model.

Abstract: In an example a method includes deriving a print agent coverage vector specifying an area coverage for each of a plurality of elements, wherein each element is associated with a print agent, a print agent combination or an absence of print agent. Deriving the print agent coverage vector comprises, for a first element of the print agent coverage vector, applying a first weighting function which varies based on an intended area color value.

Abstract: Certain examples described herein relate to updating a lookup table for an imaging system. An initial lookup table for an imaging system is obtained, the initial lookup table mapping between a first color space and a second color space. A smoothed version of the initial lookup table is also obtained. Further obtained are color property values corresponding to nodes of the lookup tables that map from a vertex-to-vertex axis of the first color space. The color property values are derived from measurements of test areas rendered by the imaging system. For a target node of the smoothed version of the initial lookup table that maps from the vertex-to-vertex axis, a pair of nodes in the initial lookup table are selected based on the obtained color property values. A mapped value in the second color space for the target node is updated, based on an interpolation of mapped values for the pair of nodes in the initial lookup table.

Abstract: In an example, a method includes receiving, at least one processor, object model data representing at least a portion of an object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber. An intended object placement location within the fabrication chamber may be determined, and a dimensional compensation to apply to the object model data may be determined using a mapping resource relating dimensional compensations to object placement locations. The determined dimensional compensation may be applied to the object model data to generate modified object model data using at least one processor.

Abstract: In an example, a method includes receiving, at at least one processor, object model data representing at least a portion of an object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber. At least one of a plurality of different geometrical compensation models to be applied to the object model data may be selected wherein the geometrical compensation models are to determine geometrical compensations to compensate for object deformation In additive manufacturing. An object generation operation based on a modification of the object model data using the or each selected geometrical compensation mode may be simulated and predicted attributes of the object when generated based on the or each simulation may be displayed.

Abstract: Certain examples described herein relate to generating a Neugebauer Primary area coverage (NPac) vector. In certain cases, an operating state of a printing system is determined. A first NPac vector is obtained, having an initial set of Neugebauer Primaries (NPs). The initial set of NPs comprise a NP that is not implementable with the operating state. A target set of NPs is determined on the basis of the operating state, the target set of NPs being implementable with the operating state. A second NPac vector is generated, the second NPac vector having the target set of NPs.

Abstract: In an example, a method includes receiving, at at least one processor, object model data representing at least a portion of an object that is to be generated by an additive manufacturing apparatus by fusing build material within a fabrication chamber. An intended object placement location within the fabrication chamber may be determined, and a dimensional compensation to apply to the object model data may be determined using a mapping resource relating dimensional compensations to object placement locations. The determined dimensional compensation may be applied to the object model data to generate modified object model data using at least one processor.