Detecting collisions in a simulated machining of a workpiece represented by dexels

Patent metadata

Field	Value
Publication number	US-10140395-B2
Application number	US-201514954820-A
Country	US
Kind code	B2
Filing date	Nov 30, 2015
Priority date	Dec 31, 2014
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

Such a method improves the simulating of the machining of a workpiece.

First claim

What is claimed is:

1. A computer-implemented method for simulating machining of a workpiece with a cutting tool having at least one cutting part and at least one non-cutting part, the method comprising:
providing to a machining simulation:
a set of dexels that represents the workpiece, each dexel having one or more segments, the one or more segments collectively representing the intersection between a line and the workpiece,
a trajectory of the cutting tool, the trajectory of the cutting tool being a rigid motion, and
a set of meshes each representing a respective cutting part or non-cutting part of the cutting tool;

and then, for each dexel in the provided set:
computing, for each mesh, the extremity points of all polylines that describe a time of intersection between the line of the dexel and the mesh as a function of a height of intersection, according to the trajectory of the cutting tool; and
testing a collision of the cutting tool with the workpiece along the dexel, wherein the testing includes determining if, for a value of height that corresponds to a position that belongs to a lower envelope of the set of all polylines of all meshes, the polyline to which the position belongs being associated to a non-cutting part, the value of height belongs to one of the segments of the dexel.

2. The method of claim 1 , wherein computing the extremity points of all polylines comprises, for each mesh, and for each extremity point of a respective polyline:
determining, based on all faces of the mesh associated to the respective polyline, the boundary face of a volume swept by a face of the mesh, according to the trajectory of the cutting tool, with which intersection of the line of the dexel corresponds to the extremity point; and
computing a time and a height based on the intersection between the line of the dexel and the determined boundary face.

3. The method of claim 2 , wherein computing the extremity points of all polylines further comprises, for each mesh:
determining a visible part of the mesh, the visible part being the portion of the mesh directed toward the trajectory of the cutting tool;
computing the boundary of a volume swept by the visible part, according to the trajectory of the cutting tool; and then
iterating, for each extremity point of a respective polyline, the determining of the boundary face of the volume swept by a face of the mesh, with which intersection of the line of the dexel corresponds to the extremity point, and the computing of a time and a height, wherein the determining of the boundary face consists of identifying a respective boundary face of the computed boundary of the volume swept by the visible part.

4. The method of claim 3 , wherein computing the extremity points of all polylines further comprises, for each mesh, determining adjacency information relative to volumes swept by the faces of the visible part, and for each respective polyline:
the determining of the boundary face of the volume swept by a face of the mesh, with which intersection of the line of the dexel corresponds to a first extremity point of the polyline, consists of determining, by geometrical computation, a first face of the computed boundary of the volume swept by the visible part, said first face being intersected by the line of the dexel; and
the determining of the boundary face of the volume swept by a face, with which intersection of the line of the dexel corresponds to the second extremity point of the polyline, consists of determining, by topological propagation based on the adjacency information, a second face of the computed boundary of the volume swept by the visible part, said second face being intersected by the line of the dexel.

5. The method of claim 4 , wherein the iterating is parallelized over the set of dexels.

6. The method of claim 5 , wherein the determining of first faces implements rasterization over the set of dexels.

7. The method of claim 1 , further comprising:
if a collision is detected by the testing, adjusting a component of the machining simulation based on the detected collision.

8. A method for producing a product, comprising:
in a simulation phase, repeating implementation of simulating machining of a workpiece with a cutting tool having at least one cutting part and at least one non-cutting part; and
providing after the simulation phase, a machining phase on the workpiece, wherein the simulating the machining being computer-implemented and comprising:
providing:
a set of dexels that represents the workpiece, each dexel having one or more segments, the one or more segments collectively representing the intersection between a line and the workpiece,
a trajectory of the cutting tool, the trajectory of the cutting tool being a rigid motion, and
a set of meshes each representing a respective cutting part or non-cutting part of the cutting tool;

and then, for each dexel in the provided set:
computing, for each mesh, the extremity points of all polylines that describe a time of intersection between the line of the dexel and the mesh as a function of a height of intersection, according to the trajectory of the cutting tool; and
testing a collision of the cutting tool with the workpiece along the dexel, wherein the testing includes determining if, for a value of height that corresponds to a position that belongs to a lower envelope of the set of all polylines of all meshes, the polyline to which the position belongs being associated to a non-cutting part, the value of height belongs to one of the segments of the dexel.

9. The method of claim 8 , further comprising:
if a collision is detected by the testing, adjusting a component of the machining simulation based on the detected collision.

10. A computer program product comprising:
a non-transitory computer readable storage medium having recorded thereon a data structure including specifications of a simulation of machining of a workpiece with a cutting tool having at least one cutting part and at least one non-cutting part; and
computer-implemented simulation instructions carried on the computer readable storage medium including instructions for:
providing to a machining simulation:
a set of dexels that represents the workpiece, each dexel having one or more segments, the one or more segments collectively representing the intersection between a line and the workpiece,
a trajectory of the cutting tool, the trajectory of the cutting tool being a rigid motion, and
a set of meshes each representing a respective cutting part or non-cutting part of the cutting tool;

and then, for each dexel in the provided set:
computing, for each mesh, the extremity points of all polylines that describe a time of intersection between the line of the dexel and the mesh as a function of a height of intersection, according to the trajectory of the cutting tool; and
testing a collision of the cutting tool with the workpiece along the dexel, wherein the testing includes determining if, for a value of height that corresponds to a position that belongs to a lower envelope of the set of all polylines of all meshes, the polyline to which the position belongs being associated to a non-cutting part, the value of height belongs to one of the segments of the dexel.

11. The computer program product of claim 10 , wherein the computer readable storage medium further including instructions for:
when a collision is detected by the testing, adjusting a component of the machining simulation based on the detected collision.

12. A system comprising:
a processor coupled to a memory;
the memory having recorded thereon instructions for performing a computer-implemented simulating of machin

Assignees

• Dassault Systemes

Inventors

• Montana Nicolas
• Nosenzo Romain

Classifications

• G06F30/367 Primary

  Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods · CPC title

• G05B2219/35346

  VMMC: virtual machining measuring cell simulate machining process with modeled errors, error prediction · CPC title

• Y02T10/82

  Elements for improving aerodynamics · CPC title

• G05B2219/40091

  Tele-programming by graphical simulation · CPC title

• G05B19/4069 Primary

  Simulating machining process on screen (G05B19/4068 takes precedence) · CPC title