# US 7,940,262 B2 · Unification and part hiding in three dimensional geometric data > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,940,262 B2 - Document ID: US7940262B2 - Status: Granted - Kind: B2 - Application number: 11/763,585 - Filed: 2007-06-15 - Published: 2007-12-20 - Granted: 2011-05-10 - Earliest claimed: 2006-06-15 - Assignees: Right Hemisphere Limited - Inventors: Max Konev; Mark Shafer; Jed Fisher - Web page: https://patentgrep.com/patent/US7940262B2 ## CPC - G06T 15/40: Hidden part removal - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract Technology is disclosed for improving the rendering of a three-dimensional (3D) object. In one aspect, the technology applies multi-scale visibility patches and adjacency heuristics to restore proper face and normals orientation at a per-object and per-polygon level; and target where best to apply ray-casting metrics to refine visibility determination. ## Claims ### Claim 1 A computer implemented method for improving a rendering of a view in a three dimensional scene of a Computer Aided Design (CAD) object, the view comprising a plurality of polygons visible from a variety of viewing angles, comprising: receiving the CAD object from a first processing device; outputting healed visualization data based on the CAD object by: removing internal parts of the object defined in the scene, the internal parts being hidden in the plurality of viewing angles; and unifying portions of the scene on a per object and per polygon level by applying, for a first set of triangles, a heuristic to determine proper normal orientation for a triangle face and for a second set of triangles, selectively applying a ray-casting technique to determine proper normal orientation. ### Claim 2 (depends on 1) The computer implemented method of claim 1 wherein the step of removing internal parts comprises: spatially classifying a tessellated mesh comprising a plurality of triangles representing at least one polygon; directing rays from a subset of the plurality of viewing angles through the mesh; determining which parts are intercepted; and calculating a ratio of positive to negative hits and if the ratio is zero, removing a part from the object rendering. ### Claim 3 (depends on 2) The computer implemented method of claim 2 wherein the step of spatially classifying the tessellated mesh includes classifying the mesh into a grid-volume approximation and the step of determining comprises performing a ray-intersection test on each ray and at least one triangle. ### Claim 4 (depends on 3) The computer implemented method of claim 3 further including determining orientation direction of each intersecting triangle based on a sign of a dot-product determination of the ray-intersection test. ### Claim 5 (depends on 4) The computer implemented method of claim 4 wherein the step of unifying includes the steps of determining patches within the polygon based on connectivity between the triangles. ### Claim 6 (depends on 5) The computer implemented method of claim 5 further including the step of mapping connectivity information for each triangle into a data structure. ### Claim 7 (depends on 6) The computer implemented method of claim 6 further including determining for each triangle in each polygon a first possible growth path direction for a patch, testing the growth path, and setting a boundary or growing a patched in said direction based on said testing, thereby providing at least one patch. ### Claim 8 (depends on 7) The computer implemented method of claim 7 further including processing the patch to determine a correct direction of a normal for the patch. ### Claim 9 (depends on 8) The computer implemented method of claim 8 wherein the step of processing the patch includes: finding a current patch and a neighbor patch, the neighbor patch having strongest evidence of inversion relative to other neighbor patches; and determining whether the connectivity mapping information exceeds a threshold, and if so, marking the neighbor as inverted and if not, performing ray-casting on the neighbor. ### Claim 10 (depends on 9) The computer implemented method of claim 9 further including setting the neighbor patch as a current patch and repeating said steps of finding and determining. ### Claim 11 A computer implemented process for creating three dimensional object view data, comprising: receiving a CAD object from a first processing device; outputting healed visualization data based on the CAD object by: accessing three dimensional object data comprising a plurality of polygons having borders; removing internal parts of the object in a scene, the internal parts being hidden when rendering the three dimensional object in a plurality of viewing angles; and unifying portions of the object and applying evidence based heuristics to determine a normal direction for at least a subset of unified portions by applying, for a first set of triangles, a heuristic to determine proper normal orientation for a face and for a second set of triangles, applying a ray-casting technique to determine proper normal orientation. ### Claim 12 (depends on 11) The process of claim 11 wherein said step of applying ray-casting is performed for each unified portion having a normal direction not determined by applying evidence based heuristics. ### Claim 13 (depends on 11) The process of claim 11 wherein the step of unifying includes the steps of determining patches within the polygon based on connectivity between the triangles. ### Claim 14 (depends on 13) The process of claim 13 further including the step of mapping connectivity information for each triangle into a data structure. ### Claim 15 (depends on 14) The process of claim 14 further including determining for each triangle in each polygon a first possible growth path direction for a patch, testing the growth path, and setting a boundary or growing a patched in said direction based on said testing, thereby providing at least one patch. ### Claim 16 (depends on 15) The process of claim 15 further including processing the patch to determine a correct direction of a normal for the patch, said processing comprising: finding a current patch and a neighbor patch with strongest evidence of inversion relative to other neighbor patches; and determining whether the connectivity mapping information exceeds a threshold, and if so, marking the neighbor as inverted and if not, performing ray-casting on the neighbor. ### Claim 17 (depends on 11) The process of claim 11 wherein the step of removing internal parts comprises: spatially classifying a tessellated mesh comprising a plurality of triangles representing at least one polygon; directing rays from a subset of the plurality of viewing angles through the mesh; determining which parts are intercepted; and calculating a ratio of positive to negative hits and if the ratio is zero, removing the part from the object rendering. ### Claim 18 A non-transitory computer readable medium having instructions stored thereon, the instructions causing a processing device to execute a method comprising: accessing a three dimensional CAD object data comprising a plurality of polygons having borders; and outputting healed visualization data based on the CAD object by: removing internal parts of the object in a scene, the internal parts being hidden when rendering the three dimensional object in a plurality of viewing angles; unifying portions of the object and applying evidence based heuristics to determine a normal direction for at least a first set of triangles to determine proper normal orientation for a triangle face and for a second set of triangles, selectively applying ray-casting to determine a normal direction a second subset of the triangles; and rendering the three dimensional object using the healed visualization data.