# US 2014/0192049 A1 · Medial surface generation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192049 A1 - Document ID: US20140192049A1 - Status: Published application - Kind: A1 - Application number: 14/083,174 - Filed: 2013-11-18 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: ROLLS-ROYCE plc - Applicants: Rolls-Royce PLC. - Inventors: Felix STANLEY; Surya Mohan PRERAPA - Web page: https://patentgrep.com/patent/US20140192049A1 ## CPC - G06T 15/10: Geometric effects - G06T 17/20: Finite element generation, e.g. wire-frame surface description, {tesselation} - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A method of generating a medial mesh of an object. The method first includes obtaining a surface mesh of the object. Define a set of node normal vectors, each having its origin at a node and being directed towards the interior of the object. For each node: select a node normal from the set having their origins at that node; define a sphere wherein a surface of the sphere includes the node and the centre point is positioned at a scalar multiple of the node normal; increment the centre point along the scalar multiple; iterate until the surface of the sphere includes another node or element. The centre point is recorded as a medial point and the diameter as a thickness. The medial mesh is generated from the set of medial points and object thicknesses. ## Claims ### Claim 1 A method of generating a medial mesh of an object, the object having an interior; the method comprising steps to: a) obtain a surface mesh of the object comprising elements whose vertices are nodes; b) define a set of node notuial vectors, each node normal having its origin at a node and being directed towards the interior of the object; c) for each node: i. select a node normal from the set of node normals having their origins at that node; ii. define a sphere wherein a surface of the sphere includes the node and wherein a centre point of the sphere is positioned at a scalar multiple of the node normal; iii. increment the centre point along the scalar multiple of the node normal; iv. iterate steps ii and iii until the surface of the sphere includes another node or element; v. record the centre point of the sphere as a medial point and the diameter of the sphere as a thickness; vi. repeat steps i to v for each node normal from the set of node normals having their origins at that node; and d) generate a medial mesh from the set of medial points and record object thickness from the set of thicknesses. ### Claim 2 (depends on 1) A method as claimed in claim 1 comprising a further step to: a) manipulate the medial mesh. ### Claim 3 (depends on 1) A method as claimed in claim 1 comprising a further step to: a) recreate the surface mesh or the object geometry from the medial mesh and the object thickness. ### Claim 4 (depends on 1) A method as claimed in claim 1 wherein step 1.c) is performed in parallel for at least a subset of the nodes. ### Claim 5 (depends on 1) A method as claimed in claim 1 wherein the surface mesh is at least partially disjointed. ### Claim 6 (depends on 1) A method as claimed in claim 1 wherein the surface mesh is at least partially non-conformal. ### Claim 7 (depends on 1) A method as claimed in claim 1 wherein step 1.a) includes determining element normals directed outside the object. ### Claim 8 (depends on 7) A method as claimed in claim 7 wherein each node normal is parallel to an element normal and is directed towards the interior of the object. ### Claim 9 (depends on 1) A method as claimed in claim 1 comprising a further step to set the number of node normals such that: a surface node comprises one node normal; an edge node comprises two node normals; and a vertex node comprises three node normals. ### Claim 10 (depends on 9) A method as claimed in claim 9 comprising a further step to classify the edge nodes and vertex nodes such that: an edge node or vertex node for which all the node normals cross in the interior of the object is a convex node; an edge node or vertex node for which all the node normals cross outside the object is a concave node; and a vertex node for which two of the node normals cross in the interior of the object and two of the node normals cross outside the object is a convex-concave node. ### Claim 11 (depends on 9) A method as claimed in claim 9 wherein for each edge node or vertex node step 1.c) further comprises steps between step 1.c)iv and step 1.c)v to: vii. increment the centre point position further along the scalar multiple of the node normal; viii. project a new node from the centre point position to a nearest surface mesh element; ix. perform steps 1.c)ii to 1.c)iv from the new node; and x. iterate steps vii to ix until a sphere maximal diameter is found. ### Claim 12 (depends on 1) A method as claimed in claim 1 wherein step 1.c)iii comprises steps to: a) calculate a distance between the centre point and a nearest surface mesh element; b) sum the distance calculated and the previous radius; c) halve the sum; and d) set the result as a new radius. ### Claim 13 (depends on 1) A method as claimed in claim 1 wherein step 1.c)iv comprises iterating until the surface of the sphere is within a tolerance threshold of including another node or element. ### Claim 14 (depends on 1) A method as claimed in claim 1 wherein the surface mesh comprises 3-dimensional or 2-dimensional geometry. ### Claim 15 (depends on 1) A method as claimed in claim 1 wherein the object comprises any one of the group comprising: a component; a subsystem; a gas turbine engine; an animation object. ### Claim 16 (depends on 1) A method as claimed in claim 1 wherein step 1.a) comprises deriving the surface mesh from the object or looking up the surface mesh from a reference source. ### Claim 17 (depends on 1) A computer program having instructions adapted to carry out the method according to claim 1. ### Claim 18 (depends on 1) A computer readable medium, having a computer program recorded thereon, wherein the computer program is adapted to make the computer execute the method according to claim 1. ### Claim 19 (depends on 18) A computer program comprising the computer readable medium as claimed in claim 18.