A method of calibrating an apparatus for generating a three-dimensional object is described in which a calibration substrate is generated by depositing build material and applying energy to the build material to form a fused surface; a calibration pattern is generated on the calibration substrate by depositing an agent on the calibration surface according to a predetermined pattern; and an attribute of the calibration pattern is measured.

A method of calibrating an apparatus for generating a three-dimensional object is described in which a calibration substrate is generated by depositing build material and applying energy to the build material to form a fused surface; a calibration pattern is generated on the calibration substrate by depositing an agent on the calibration surface according to a predetermined pattern; and an attribute of the calibration pattern is measured.

A method for processing an object for printing, the object comprising a plurality of properties defined at each of a plurality of locations within the object, each property represented by a metamer set of possible combinations of proportions of at least one of a set of printing materials, the method comprising: selecting a combination of the metamer sets of a given location within an object that provides all of the plurality of properties defined for the given location.

A method for processing an object for printing, the object comprising a plurality of properties defined at each of a plurality of locations within the object, each property represented by a metamer set of possible combinations of proportions of at least one of a set of printing materials, the method comprising: selecting a combination of the metamer sets of a given location within an object that provides all of the plurality of properties defined for the given location.

Methods and apparatus associated with three-dimensional objects are described. In an example, a method comprises receiving data representing a three-dimensional model object, the data comprising object model data and object property data. For at least one object property, a sub-region of the object in which the object property is non-variable is identified and, for at least one location within the object, all sub-regions in which the location is situated are identified. Based on the combination of identified sub-regions for a location, print material data is determined for the location. Control data for the production of a three-dimensional object is generated according to the print material data.

Methods and apparatus associated with three-dimensional objects are described. In an example, a method comprises receiving data representing a three-dimensional model object, the data comprising object model data and object property data. For at least one object property, a sub-region of the object in which the object property is non-variable is identified and, for at least one location within the object, all sub-regions in which the location is situated are identified. Based on the combination of identified sub-regions for a location, print material data is determined for the location. Control data for the production of a three-dimensional object is generated according to the print material data.

Methods and apparatus relating to substructures for 3D objects are described. In an example, a method for providing a three-dimensional halftone threshold matrix is described. The method may comprise receiving a substructure model representing a three-dimensional material structure and populating each location in the substructure model at which the structure exists with a halftone threshold value.

Methods and apparatus relating to substructures for 3D objects are described. In an example, a method for providing a three-dimensional halftone threshold matrix is described. The method may comprise receiving a substructure model representing a three-dimensional material structure and populating each location in the substructure model at which the structure exists with a halftone threshold value.

Systems, devices, and methods according to the present disclosure are configured for use in additive manufacturing, e.g. 3D printing. Various materials, including thermoplastic materials, can be used with an additive manufacturing system to create a part composite. Systems, devices, and methods described herein can be used to identify a characteristic of a material or of a material container for use with an additive manufacturing system. The identified characteristic can be used to determine an authenticity of the material. Based on the authenticity, one or more features or functions of the additive manufacturing system can be updated. The characteristic of the material may be optical information on the container of the material, e.g. a bar code, may be identified by emitting x-ray radiation and receiving a spectral characteristic, may be an electrical or magnetic characteristic or may be engraved on the surface of the material itself.

Systems, devices, and methods according to the present disclosure are configured for use in additive manufacturing, e.g. 3D printing. Various materials, including thermoplastic materials, can be used with an additive manufacturing system to create a part composite. Systems, devices, and methods described herein can be used to identify a characteristic of a material or of a material container for use with an additive manufacturing system. The identified characteristic can be used to determine an authenticity of the material. Based on the authenticity, one or more features or functions of the additive manufacturing system can be updated. The characteristic of the material may be optical information on the container of the material, e.g. a bar code, may be identified by emitting x-ray radiation and receiving a spectral characteristic, may be an electrical or magnetic characteristic or may be engraved on the surface of the material itself.