Abstract: In some examples, an additive manufacturing system includes a dispensing device, an applicator, a thermal energy source, a thermal imaging device, and a controller. The controller is to cause the dispensing device to deposit a layer of build material and cause the applicator to apply the fusing agent to form an object portion and to apply the detailing agent to form a reference portion in the layer of build material. The controller is to cause the thermal energy source to heat the reference portion and to heat and fuse the object portion and cause the thermal imaging device to measure a temperature of the reference portion. The controller is to regulate a power level of the thermal energy source based on a comparison between the temperature of the reference portion and a set-point for the reference portion, which is based on a target temperature for the object portion.

Abstract: According to examples, an apparatus may include a processor and a memory on which is stored machine readable instructions that may cause the processor to identify a color of a portion of a 3D object to be fabricated from a 3D model and to determine, based on the identified color of the portion, a property of a thermal support, in which the property may affect a temperature of an area near build material particles used to form the portion. The instructions may cause the processor to instruct fabrication components to fabricate the thermal support having the determined property and the fabrication components to fabricate the 3D object. The thermal support may be fabricated at a location with respect to the portion to increase a temperature of a set of particles used to fabricate the portion during fabrication of the portion.

Abstract: A system determines an object part density relative to a build region in a layer of build material used in an additive manufacturing machine, the object part density based on a relative portion of the build region where an energy absorbing agent is applied. The system controls a thermal characteristic of the build region in the layer of build material based on the determined object part density.

Abstract: A system determines a difference in energy absorptions by a plurality of different energy absorbing agents used to form an object by an additive manufacturing machine. The system adjusts, based on the determined difference, an amount of an energy absorbing agent of the plurality of different energy absorbing agents dispensed for a build operation of the additive manufacturing machine.

Abstract: In an example, a method includes receiving, at a processor, a data model of an object to be generated in additive manufacturing. A virtual build volume comprising a representation of at least a portion of the object may be segmented into a plurality of nested segments comprising a core segment and a peripheral segment. Segmenting the virtual build volume may comprise determining a dimension of the peripheral segment based on at least one of a geometry of the object and an intended object property.

Abstract: In an example, a method includes providing a build material. Print agent comprising colorant may be applied to a first portion of the build material to be fused in additive manufacturing, wherein the print agent is applied according to a target color for the first portion. A combination of a fusion inhibiting agent and colorant may be applied to a second portion of the build material, wherein the print agent is applied according to the target color of the first portion and the second portion is adjacent to the first portion. The method may further include heating the build material by exposing the build material to radiation so as to cause fusing of the first portion.

Abstract: In an example, a method includes determining an additive manufacturing process instruction, the additive manufacturing process instruction comprising an instruction specifying a coverage of a set of print agents comprising a fusing agent and a colorant to be applied to build material. A color and a behavioural property of carrying out an additive manufacturing process according to the additive manufacturing process instruction may be determined and, in response to a determination that the behavioural property meets predetermined parameters, the instruction and the color may be added to a color mapping resource.

Abstract: In an example, a method includes receiving object model data describing at least a portion of an object to be generated by additive manufacturing. Object generation instructions for generating the object in its entirety may be derived based on the object model data. Where it is determined that the object model data comprises a data deficiency for deriving the object generation instructions, at least one attribute for the object may be inferred and object generation instructions may be derived based on the object model data and the inferred attribute.

Abstract: An example system includes a three-dimensional (3D) print engine to produce a 3D object based on voxel data associated with the 3D object and a 3D print controller to control operation of the 3D print engine. The 3D print controller having a surface normal determination portion. The surface normal determination portion is to determine a normal for at least one surface voxel of the 3D object, the determination of the normal being based on the voxel data. The 3D print controller is to cause the 3D print engine to adjust at least one print parameter based on the normal for the at least one surface voxel determined by the surface normal determination portion.

Abstract: In an example a method includes identifying, by a processor, in a data model of at least a portion of a three-dimensional object, an object property associated with a location in the three-dimensional object. A data model of a virtual build volume comprising at least a portion of the three-dimensional object may be generated in which an association with an object property is dispersed beyond the location.

Abstract: A control system for a three-dimensional printer includes an energy component interface, an agent depositing component interface, and control logic. The control logic controls the operation of an energy component through the energy component interface and an agent depositing component through the agent depositing component, in forming an output object that is specified in a print job. Additionally, in some examples, the control logic can implement a plurality of modes. Each mode, when selected modulate one or more operational parameters of a least one of the energy component or agent depositing component.

Abstract: In an example, a virtual build volume comprising a representation of at least a part of an object to be generated in additive manufacturing is segmented into a plurality of nested segments comprising a core segment, an inner peripheral segment and an outer peripheral segment. Additive manufacturing control instructions may be generated for the nested segments. The control instructions for the core segment may provide a first region of the object corresponding to the core segment and having a first color. The control instructions for the outer peripheral segment may provide a second color for a second region of the object corresponding to the outer peripheral segment. The control instructions for the inner peripheral segment may provide a third color for a third region of the object corresponding to the inner peripheral segment, wherein a color of the third region is determined so as to at least partially visually mask the first region.

Abstract: In an example, a method include receiving a data model of an object to be generated in additive manufacturing at a processor, the data model comprising object property data. A segmentation of a virtual build volume comprising at least a portion of the object into a plurality of nested segments may be derived. A first segment may be associated with first object generation parameters and a second segment may be associated with second, different, object generation parameters. A number of nested segments to be derived may be determined based on at least one of a geometry of the object and an intended object property.

Abstract: In an example of a three-dimensional printing method, a polymeric build material is applied. A fusing agent is selectively applied on at least a portion of the polymeric build material. The fusing agent includes cesium tungsten oxide nanoparticles, a zwitterionic stabilizer, and an aqueous vehicle. The polymeric build material is exposed to electromagnetic radiation to fuse the portion of the polymeric build material in contact with the fusing agent to form a layer.

Abstract: In an example of a three-dimensional printing method, a polymeric build material is applied. A fusing agent is selectively applied on at least a portion of the polymeric build material. The fusing agent includes cesium tungsten oxide nanoparticles, a zwitterionic stabilizer, and an aqueous vehicle. The polymeric build material is exposed to electromagnetic radiation to fuse the portion of the polymeric build material in contact with the fusing agent to form a layer.

Abstract: A method for inkjet nozzle spitting including conveying pages in a print direction along a transport through a printzone of a wide array printhead formed by a plurality of rows of nozzles disposed crosswise to the print direction, the nozzles to eject ink drops in accordance with print data. The method further includes maintaining a gap between pages as the gap moves through the printzone, and providing spit pattern data as print data to the printhead to successively activate each row of nozzles, in the print direction and in synchronism with movement of the gap, to eject ink drops from all nozzles of the row so that a position of the activated row of nozzles is maintained within the gap as the gap continuously moves through the printzone.

Abstract: A system and methods for modifying the values of halftoned image pixels to replace a defective colorant with at least one non-defective colorant.

Abstract: A method for producing printed articles that encompasses providing a first ink composition that contains metal oxide particles with an average particle size in the range of about 3 to about 300 nm; providing a second ink composition that contains non-particulate, light-absorbing colorants dissolved in an ink vehicle; providing a printable media having a bottom supporting substrate and an ink-absorbing layer with pore diameters that are smaller than the size of the metal oxide pigment particles; and applying, on the same print area, the first and the second ink compositions onto said printable media. Also disclosed herein a the printed articles obtained according to the present method.

Abstract: A system and methods for modifying the values of halftoned image pixels to replace a defective colorant with at least one non-defective colorant.

Abstract: An orifice health detection device includes a fixed array of ink ejecting orifices, the ink ejecting orifices configured to eject at least one ink drop, a light source that produces a light beam configured to scatter light from the at least one ejected ink drop, and a light detector configured to detect light scattered from the at least one ejected ink drop.