Abstract: Techniques of data compression involve performing a separate compression operation on each set of corresponding bits of a sequence of bit strings in which each bit string represents a number having an upper bound. Advantageously, compressing the sets of corresponding bits produces an improved compression ratio over compressing each number in the sequence. Further, decompression is straightforward as long as sequence order is preserved and the upper bound of each number in the sequence is known.

Abstract: Techniques are provided for repairing a polygon mesh that represents a three-dimensional surface, the repaired mesh comprising explicit regions that are preserved from the original mesh and implicit regions that are modified from the mesh repair operation. The explicit and implicit regions that comprise the hybrid surface meet along a “cut path” which can be located by identifying the elements of the volumetric grid where the implicit and explicit surfaces diverge. These elements comprise a path of marching cubes having faces that intersect the polygon elements of the explicit surface along the cut path. In certain embodiments the path between these intersections is selected so as to reduce deviation from the marching cube face and the path length. Once a preferred cut path is selected, the polygons that comprise the explicit surface are subdivided to conform to the cut path.

Abstract: This document describes techniques and apparatuses for 3D printing for colored models on multi-head fused-deposition modeling (FDM) printers. These techniques are capable of enabling FDM printers to create 3D objects based on colored models, in some cases by determining printer instructions for multiple printer heads based on a 3D model and color data for the surface of the 3D model. These techniques can also tailor printer instructions to characteristics of a particular type or individual FDM 3D printer.

Abstract: This document describes techniques and apparatuses for a three-dimensional (3D) cleaning object for multi-print-head 3D printing. These techniques are capable of cleaning leftover material from an active or inactive print head using a 3D cleaning object. This cleaning object is printed along with the desired 3D object, with the cleaning object retaining leftover material that may otherwise become an undesirable artifact of the desired 3D object.

Abstract: Methods and systems are disclosed for preserving thin components for three dimensional (3D) printing. An exemplary method generates a medial axis of a 3D shape and identifies components of the 3D shape that need to be preserved by applying a transform to the medial axis. The method creates an output model based at least in part on the components and an insetted shape corresponding to the 3D shape. A system includes a computing device with a processor and a memory having instructions that, if executed, cause the processor to perform operations. The operations comprise generating a medial axis of a 3D shape and applying a transform to the medial axis to identify one or more components of the shape to be preserved. The operations further comprise creating an output model based at least in part on the one or more components and an insetted shape corresponding to the 3D shape.

Abstract: Methods and systems for defining adaptive support structures for three dimensional (3D) printing are disclosed. An exemplary method detects an area of a 3D model needing support and generates contact points for the area. The method creates a set of virtual supports that extend downward from respective contact points and then identifies connections between the virtual supports in the set, the connections satisfying connection constraints. Next, a virtual support in the set is selected to be a trunk based on comparing connectivity levels of virtual supports in the set, the connectivity level of each of the virtual supports determined by a number of connections between the respective virtual support and other virtual supports. The method then defines a support structure originating from the contact points and including the trunk, at least one virtual support connected to the trunk, and connections between the trunk and the at least one virtual support.

Abstract: Methods and apparatus for improving printability of a three-dimensional model are disclosed. For a computer-based three-dimensional model to be generated by a three-dimensional printing system, a three-dimensional printability analysis of the model is performed. The three-dimensional printability analysis applies one or more test cases representing forces that may be applied to the model. The three-dimensional printability analysis generates one or more points at which stresses associated with the test case exceed the structural tolerances of a material to be used by the three-dimensional printing system for a fabrication of the model. For each point of the one or more points, one or more corrections to the model designed to decrease the stresses associated with a respective test case are calculated. For each test case, the corrections are evaluated. The evaluating includes selecting a preferred correction based on one or more criteria.