Three-dimensional object representation

1. A method comprising:

receiving data representing a geometrical description of a three-dimensional object defining, in a geometric space, an object geometry of the three-dimensional object;

receiving at least one object property description describing, in an object property space, an object property of the three-dimensional object; and

intersecting the object property space and the geometric space to define an object model of the three-dimensional object, wherein the object model comprises at least one object property of the three-dimensional object defined at an intersection between a described object property and a defined object geometry of the three-dimensional object.

2. The method according to claim 1 , further comprising converting at least one object property description into the geometric space of the geometrical description.

3. The method according to claim 1 wherein the data representing the geometrical description comprises a plurality of geometric vertices, each of the plurality of geometric vertices being indicative of a location in geometric space, and wherein the object model comprises the plurality of geometric vertices and at least one non-geometric vertex defining the at least one object property at the intersection.

4. The method according to claim 1 , wherein the object model comprises the geometric description and a plurality of object description vectors, wherein the object description vectors are based on described object properties at an intersection of the object property space and the geometric space.

5. The method according to claim 1 , wherein the at least one object property description comprises an indexed array of unique object property value data objects and a set of locations associated with an index of the indexed array.

6. The method according to claim 1 , further comprising receiving an initial object property description comprising object property value data objects associated with each of a plurality of locations within the object property space;

identifying distinct object property value data objects from the object property value data objects;

populating an indexed array with the distinct object property value data objects, wherein data indicative of each distinct object property value data object is stored at a different index within the array; and

generating data comprising a new object property description, the data comprising the new object property description comprising an index associated with each of a plurality of locations within the object property space, wherein the index corresponds to the index of the object property value data object for a respective location of the plurality of locations.

7. The method according to claim 1 , further comprising receiving a plurality of object property descriptions, each of the plurality of object property descriptions describing at least one object property of the three-dimensional object.

8. A method comprising:

receiving an initial object property description comprising object property value data objects associated with each of a plurality of locations within an object property space;

identifying distinct object property value data objects from the object property value data objects;

populating an indexed array with the distinct object property value data objects, wherein data indicative of each distinct object property value data object is stored at a different index within the array;

generating an object property description comprising an index associated with each of the plurality of locations within the object property space, wherein the index associated with each of the plurality of locations within the object property space corresponds to the index of the object property value data object for that location; and

intersecting the generated object property description with a geometric description of a three-dimensional object.

9. The method according to claim 8 , wherein the geometric description is a description of the geometry of the three-dimensional object in a geometric space, and the method comprises converting the locations within the object property space to locations within the geometric space.

10. The method according to claim 8 , wherein the geometric description is a description of the three-dimensional object in a geometric space using a geometric coordinate system, and wherein the locations within the object property space are specified as coordinates in an object space coordinate system, and wherein the method further comprises converting the coordinates of the object space coordinate system into coordinates of the geometric coordinate system.

11. A processing apparatus, comprising:

an interface to receive object model data, the object model data comprising a geometric description of a three-dimensional object in a geometric space, and object property data describing at least one object property of the three-dimensional object across an object property space;

a processor; and

a memory on which are stored instructions that when executed by the processor are to cause the processor to:

express the object property data in the geometric space when the object property space is specified differently from the geometric space of the geometric description; and

combine the geometric description and the object property data by intersecting the geometric description and the object property data and assigning object properties of the object property data to the geometric description of the three-dimensional object.

12. The processing apparatus according to claim 11 , wherein the geometric description comprises an array of voxels and the instructions are further to cause the processor to assign an object property to a voxel of the array of voxels.

13. The processing apparatus according to claim 11 , wherein the instructions are further to cause the processor to map data indicative of an object property to a print material coverage representation.

14. The processing apparatus according to claim 13 , wherein the instructions are further to cause the processor to generate control data from the print material coverage representation.

15. The processing apparatus according to claim 14 , wherein the control data comprises a set of discrete print material choices.