Combining additive and conventional manufacturing techniques to improve manufacturability

Patent metadata

Field	Value
Publication number	US-11086294-B2
Application number	US-201715841008-A
Country	US
Kind code	B2
Filing date	Dec 13, 2017
Priority date	Apr 12, 2017
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A design engine analyzes a complex polygonal mesh to identify regions of that mesh that can be simplified. The design engine then replaces those identified regions with simplified geometry that is more easily fabricated using traditional techniques. The remaining complex regions of the mesh are fabricated using additive fabrication techniques. The design engine interacts with both a traditional fabrication device and an additive fabrication device to fabricate the simplified and complex regions of the mesh, respectively. In this manner, a hybrid 3D structure is generated that includes both simplified geometry and complex geometry.

First claim

The invention claimed is:

1. A computer-implemented method for generating a polygonal mesh, the method comprising:
determining that a geometry for a first region included in an initial mesh has a first shape that is not suitable for non-additive fabrication, wherein the first shape is determined based on a sphere that is centered within the first region and intersects two portions of the initial mesh on opposite sides of a center of the sphere;
determining a representative cross section along a centerline associated with the first region;
in response to determining that the geometry for the first region has the first shape that is not suitable for non-additive fabrication, generating a modified geometry for the first region that is suitable for non-additive fabrication based on the representative cross section; and
replacing the first region with the modified geometry in the initial mesh to generate the polygonal mesh.

2. The computer-implemented method of claim 1 , further comprising determining that a second region included in the initial mesh does not meet a geometric criterion by:
generating a sphere centered within the second region; and
determining that the number of contiguous portions of the initial mesh that intersect the sphere is not equal to two.

3. The computer-implemented method of claim 1 , further comprising generating the centerline by extrapolating one or more centerline points based on a seed point that resides within the first region.

4. The computer-implemented method of claim 3 , further comprising generating the seed point by:
projecting a ray from a first polygon to a second polygon, wherein the first polygon and the second polygon reside in the first region;
computing a first midpoint along the ray between the first polygon and the second polygon;
generating a sphere centered at the first midpoint;
determining a first intersection zone where the sphere intersects the first region;
computing a first centroid associated with the first intersection zone;
determining a second intersection zone where the sphere intersects the first region;
computing a second centroid associated with the second intersection zone;
generating a line segment from the first centroid to the second centroid;
computing a second midpoint associated with the line segment;
generating a third cross section by transecting the first region at the second midpoint; and
computing a third centroid associated with the third cross section to generate the seed point.

5. The computer-implemented method of claim 3 , further comprising generating at least one centerline point by:
generating a first cross section by transecting the first region proximate to the seed point;
computing a first centroid based on the first cross section;
generating a difference vector between the seed point and the first centroid;
extending the difference vector from the first centroid to an intermediate point;
generating a second cross section by transecting the first region at the intermediate point; and
computing a second centroid associated with the second cross section to generate the at least one centerline point, wherein the centerline includes the seed point and the at least one centerline point.

6. The computer-implemented method of claim 1 , further comprising performing one or more post-processing operations that include replacing at least a portion of the centerline with a b-spline or a line segment.

7. The computer-implemented method of claim 1 , wherein determining the representative cross section comprises:
transecting the first region at a set of positions along the centerline to generate a set of cross sections;
assigning a class to each cross section;
determining which class is the most commonly assigned class across the set of cross sections; and
designating the most commonly assigned class as the representative cross section.

8. The computer-implemented method of claim 1 , wherein generating modified geometry for the first region comprises extruding the representative cross section along the centerline.

9. One or more non-transitory computer-readable media storing program instructions that, when executed by one or more processors cause the one or more processors to generate a polygonal mesh by performing the steps of:
determining that a geometry for a first region included in an initial mesh has a first shape that is not suitable for non-additive fabrication, wherein the first shape is determined based on a sphere that is centered within the first region and intersects two portions of the initial mesh on opposite sides of a center of the sphere;
determining a representative cross section along a centerline associated with the first region;
in response to determining that the geometry for the first region has the first shape that is not suitable for non-additive fabrication, generating a modified geometry for the first region that is suitable for non-additive fabrication based on the representative cross section; and
replacing the first region with the modified geometry in the initial mesh to generate the polygonal mesh.

10. The one or more non-transitory computer-readable media of claim 9 , wherein the step of determining that the first region has the first shape that is not suitable for non-additive fabrication comprises
determining that a ratio between sizes of the two portions of the initial mesh falls beneath a threshold.

11. The one or more non-transitory computer-readable media of claim 9 , further comprising the step of determining that a second region included in the initial mesh does not meet a geometric criterion by:
generating a sphere centered within the second region;
determining that exactly two portions of the initial mesh intersect the sphere on opposite sides of a center of the sphere; and
determining that a ratio between sizes of the two portions of the initial mesh exceeds a threshold.

12. The one or more non-transitory computer-readable media of claim 9 , further comprising the step of generating the centerline by extrapolating one or more centerline points based on a seed point that resides within the first region.

13. The one or more non-transitory computer-readable media of claim 12 , further comprising generating the seed point by:
projecting a ray from a first polygon to a second polygon, wherein the first polygon and the second polygon reside in the first region;
computing a first midpoint along the ray between the first polygon and the second polygon;
generating a sphere centered at the first midpoint;
determining a first intersection zone where the sphere intersects the first region;
computing a first centroid associated with the first intersection zone;
determining a second intersection zone where the sphere intersects the first region;
computing a second centroid associated with the second intersection zone;
generating a line segment from the first centroid to the second centroid;
computing a second midpoint associated with the line segment;
generating a third cross section by transecting the first region at the second midpoint; and
computing a third centroid associated with the third cross section to generate the seed point.

14. The one or more non-transitory computer-readable media of claim 12 , further comprising generating at least one centerline point by:
generating a first cross section by transecting the first region proximate to the seed point;
computing a first centroid based on the first cross section;
generating a difference vector between the seed point and the first centroid;
extending the difference vector from the first centroid to an interm

Assignees

• Autodesk Inc

Inventors

• Grafen Niels
• Iorio Francesco
• Morris Nigel
• Butscher Adrian

Classifications

• G06F2113/10

  Additive manufacturing, e.g. three-dimensional [3D] printing · CPC title

• G06F30/10

  Geometric CAD · CPC title

• G05B2219/49007

  Making, forming 3-D object, model, surface · CPC title

• G06F2119/18

  Manufacturability analysis or optimisation for manufacturability · CPC title

• G06F30/00

  Computer-aided design [CAD] · CPC title