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: An example method to control a 3D printing system is described. In that example a print agent is selectively deposited onto a portion of a build material layer and based on a reflectance of the portion of the build material layer, an amount of energy to be applied to the portion is determined.

Abstract: An example method includes acquiring a model of an object to be generated in three-dimensional object generation which is segmented into a plurality of object model sub-volumes, each sub-volume representing a region of the object which is individually addressable in object generation. Object model sub-volumes within a first depth of an object model surface are defined at a first resolution and object model sub-volumes beyond the first depth are defined at a second resolution, and the first resolution is a higher resolution than the second resolution. An object generation model is applied to the object model to determine at least one predicted dimensional deviation of the object in object generation. A geometric adjustment to the segmented object model may be determined to compensate for the predicted dimensional deviation by adding and/or removing at least one object model sub-volume defined at the first resolution.

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: 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, object model data representing at least a portion of an object defining an initial object geometry is received, wherein the object is to be generated by an additive manufacturing apparatus by fusing build material using a radiant heater. Based on a non-uniform radiant heating distribution of the additive manufacturing apparatus, a modified object geometry may be determined, wherein a local modification of the object geometry is determined based on a local radiant heating parameter determined from the non-uniform radiant heating distribution.

Abstract: In an example, a tangible machine-readable medium stores instructions which, when executed by a processor, cause the processor to evaluate a plurality of possible object generation arrangements based on a default separation distance and an enhanced separation distance, wherein the enhanced separation distance is used to assess predefined object sub-portions.

Abstract: In an example, a method includes generating a training dataset for an inference model to generate dimensional modifications to apply to object models to compensate for departures from model dimensions in objects generated using additive manufacturing based on those object models. Generating the training dataset may include acquiring, for each of a plurality of generated objects, (i) an indication of a first dimensional inaccuracy and a second dimensional inaccuracy, wherein the first and second dimensional inaccuracies are acquired in a direction of a first axis and relate to respective first and second object dimensions; and (ii) an indication of object placement within a fabrication chamber during object generation.

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: 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: An example method for cooling a build volume is described. In one implementation, a heating mechanism is set to a temperature identified based on the build material information, and the build volume is heated using the heating mechanism for a time period identified based on the build material information.

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.

Abstract: In an example, mesh model data representing at least a portion of a print job to be generated by an additive manufacturing apparatus by solidifying build material is received at a processor. Using a processor and based on the mesh model data, it is validated whether the three-dimensional print job described by the mesh model data conforms with at least one of material-dependent shape constraints and apparatus-dependent shape constraints of the additive manufacturing apparatus. If the result of the validation is positive, the mesh model data is rendered, using a processor for manufacturing the three-dimensional print job by an additive manufacturing apparatus. If the result of the validation is negative, a predetermined action is performed.

Abstract: A method of adjusting a three-dimensional representation of an object to be manufactured in an additive manufacturing process comprises determining a processing operation to be applied to the object, and adjusting the three-dimensional representation of the object based on adjustment parameters associated with the processing operation.

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.

Abstract: In an example, a method includes generating a training dataset for an inference model to generate dimensional modifications to apply to object models to compensate for departures from model dimensions in objects generated using additive manufacturing based on those object models. Generating the training dataset may include acquiring, for each of a plurality of generated objects, (i) an indication of a first dimensional inaccuracy and a second dimensional inaccuracy, wherein the first and second dimensional inaccuracies are acquired in a direction of a first axis and relate to respective first and second object dimensions; and (ii) an indication of object placement within a fabrication chamber during object generation.

Abstract: An example method for cooling a build volume is described. In one implementation, a heating mechanism is set to a temperature identified based on the build material information, and the build volume is heated using the heating mechanism for a time period identified based on the build material information.