Processing three-dimensional object data for storage

An apparatus comprising:

• a processor;
• and
• a machine-readable storage medium on which is stored machine-readable instructions that, when executed by the processor, cause the processor to:
• obtain data representing a three-dimensional object to be printed, the data comprising object property data indicative of properties of the three-dimensional object;
• identify layers within the three-dimensional object to be printed;
• process the obtained data by comparing object property data associated with an identified layer to object property data associated with a reference layer selected from the identified layers;
• and
• responsive to determining a difference between the object property data associated with the identified layer and the object property data associated with the reference layer, store the determined difference on the machine-readable storage medium in place of the object property data associated with the identified layer,
• wherein the determined difference is stored in a three-dimensional file format for printing that includes geometry information of the three-dimensional object and per layer information of the identified layers, the per layer information including the determined difference.

A non-transitory machine-readable storage medium encoded with instructions executable by a processor that, when executed by the processor, cause the processor to:

• obtain data representing a three-dimensional object to be printed, the data comprising object property data representing properties of the three-dimensional object;
• identify slices within the three-dimensional object to be printed;
• process the obtained data by comparing object property data in respect of an identified slice to object property data in respect of a key frame chosen from the identified slices;
• and
• responsive to determining a difference between the object property data associated with the identified slice and the object property data associated with the key frame, store the determined difference,
• wherein the determined difference is stored in a three-dimensional file format for printing that includes geometry information of the three-dimensional object and per layer information of the identified layers, the per layer information including the determined difference.