Techniques for Automatically Placing Escape Holes during Three-Dimensional Printing

Patent metadata

Field	Value
Publication number	US-2016136883-A1
Application number	US-201414544034-A
Country	US
Kind code	A1
Filing date	Nov 17, 2014
Priority date	Nov 17, 2014
Publication date	May 19, 2016
Grant date	—

Abstract

In one embodiment of the present invention, an escape hole generator creates escapes holes designed to facilitate removal of support and/or unprinted material generated inside enclosed hollows of three-dimensional (3D) digital models during 3D printing. In operation, the escape hole generator identifies a hollow included in the three-dimensional model and then selects optimized locations for escape holes. Notably, the escape hole generator selects the locations to optimize placement heuristics, such as favoring locations closer to the bottom of the 3D model, while satisfying escape hole constraints (e.g., hole size and spacing requirements). The escape hole generator then perforates the hollow at the selected locations with geometries that provide channels from the outer surface of the hollow to the outer surface of the hollow. Advantageously, automating escape hole generation enables efficient creation of hollowed 3D models that reduce 3D printing time and material usage compared to solid 3D model counterparts.

First claim

The invention claimed is:

1 . A computer-implemented method for automatically placing one or more escape holes when printing a three-dimensional model, the method comprising:
identifying a hollow region of a three-dimensional model; determining a first location for a first escape hole based on the hollow region, an initial heuristic, and one or more escape hole constraints; and generating the first escape hole to provide a channel from the interior of the hollow region to the exterior of the hollow region at the first location.

2 . The method of claim 1 , further comprising:
determining a second location of a second escape hole based on the hollow region, a subsequent heuristic, and the one or more hole constraints; and generating a second escape hole that provides a channel from the interior of the hollow region to the exterior of the hollow region at the second location.

3 . The method of claim 1 , wherein the hollow region is represented by a three-dimensional mesh, and generating the first escape hole comprises:
generating hole geometry based on the first location; and performing a Boolean subtraction operation that perforates the three-dimensional mesh with the hole geometry.

4 . The method of claim 3 , wherein the first location is disposed on an inner shell of the hollow region, and generating the hole geometry comprises:
calculating a surface normal to the inner shell at the first location; determining, based on the surface normal, a point on an outer shell of the hollow region where a ray intersects the outer shell; and generating a three-dimensional tubular object that spans from the first location disposed on the inner shell to the point on the outer shell and is aligned with an axis corresponding to the surface normal.

5 . The method of claim 4 , wherein the three-dimensional tubular object is a truncated cone that varies in diameter between a first radius at the inner shell to a second radius at the outer shell, wherein the second radius is less than the first radius.

6 . The method of claim 4 , wherein generating the hole geometry further comprises:
identifying an infinite cylinder that is centered along the axis of the three-dimensional tubular object; selecting neighboring points, wherein the neighboring points are geodesically connected to the three-dimensional tubular object and lie within the infinite cylinder; and extending the three-dimensional tubular object to include the neighboring points.

7 . The method of claim 1 , wherein identifying the hollow region comprises identifying a shortest portion of the three-dimensional model that includes a lowest vertical point in the three-dimensional model and has a surface area large enough to accommodate a desired number of escape holes.

8 . The method of claim 1 , wherein the determining the first location comprises identifying the center of the bottom-most inner shell of the hollow region.

9 . A computer-readable storage medium including instructions that, when executed by a processing unit, cause the processing unit to automatically place one or more escape holes when printing a three-dimensional model by performing the steps of:
identifying a hollow region of a three-dimensional model; determining a first location for a first escape hole based on the hollow region, an initial heuristic, and one or more escape hole constraints; and generating the first escape hole to provide a channel from the interior of the hollow region to the exterior of the hollow region at the first location.

10 . The computer-readable storage medium of claim 9 , further comprising:
determining a second location of a second escape hole based on the hollow region, a subsequent heuristic, and the one or more hole constraints; and generating a second escape hole that provides a channel from the interior of the hollow region to the exterior of the hollow region at the second location.

11 . The computer-readable storage medium of claim 9 , wherein the hollow region is represented by a three-dimensional mesh, and generating the first escape hole comprises:
generating hole geometry based on the first location; and performing a Boolean subtraction operation that perforates the three-dimensional mesh with the hole geometry.

12 . The computer-readable storage medium of claim 11 , wherein the first location is disposed on an inner shell of the hollow region, and generating the hole geometry comprises:
calculating a surface normal to the inner shell at the first location; determining, based on the surface normal, a point on an outer shell of the hollow region where a ray intersects the outer shell; and generating a three-dimensional tubular object that spans from the first location disposed on the inner shell to the point on the outer shell and is aligned with an axis corresponding to the surface normal.

13 . The computer-readable storage medium of claim 12 , wherein the three-dimensional tubular object is a truncated cone that varies in diameter between a first radius at the inner shell to a second radius at the outer shell, wherein the second radius is less than the first radius.

14 . The computer-readable storage medium of claim 12 , wherein generating the hole geometry further comprises:
identifying an infinite cylinder that is centered along the axis of the three-dimensional tubular object; selecting neighboring points, wherein the neighboring points are geodesically connected to the three-dimensional tubular object and lie within the infinite cylinder; and extending the three-dimensional tubular object to include the neighboring points.

15 . The computer-readable storage medium of claim 9 , wherein identifying the hollow region comprises identifying a shortest portion of the three-dimensional model that includes a lowest vertical point in the three-dimensional model and has a surface area large enough to accommodate a desired number of escape holes.

16 . The computer-readable storage medium of claim 9 , wherein the determining the first location comprises identifying the center of the bottom-most inner shell of the hollow region.

17 . A system configured to print three-dimensional models and a plurality of support posts, the system comprising:
a processing unit configured to:
identify a first overhanging surface in a three-dimensional model based on a maximum overhang threshold, wherein the first overhanging surface includes a first contact point and a second contact point;
generate a first set of support posts that connects the first contact point to a first support point; and
generate a second set of support posts that connects the second contract point to a second support point, wherein no post included in the second set of support posts intersects the first contact point; and
a three-dimensional printing unit coupled to the processing unit and configured to implement the three-dimensional model, the first set of support posts, and the second set of support posts.

18 . The system of claim 17 , wherein the processing unit is further configured to:
determine a second location of a second escape hole based on the hollow region, a subsequent heuristic, and the one or more hole constraints; and generate a second escape hole that provides a channel from the interior of the hollow region to the exterior of the hollow region at the second location.

19 . The system of claim 17 , wherein the hollow region is represented by a three-dimensional mesh, and generating the first escape hole comprises:
generating hole geometry base

Assignees

• Autodesk Inc

Inventors

• Schmidt Ryan Michael

Classifications

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29C67/0051 Primary

  Operations & Transport · mapped topic

• B29C64/188

  involving additional operations performed on the added layers, e.g. smoothing, grinding or thickness control (surface shaping B29C59/00; after-treatment of articles without altering their shape B29C71/00) · CPC title

• B29C64/386 Primary

  Data acquisition or data processing for additive manufacturing · CPC title

• B33Y50/00

  Data acquisition or data processing for additive manufacturing · CPC title