Identification and redesign of critical thin segments below 3D printer resolution
Systems and methods may support identification and redesign of critical thin segments in a 3D model that are below 3D printer resolution. Identification of critical thin segments may include segmenting cross-sectional slices of the 3D model into printable segments and non-printable segments and using a machine learning model trained using geometrical features computed on thin regions to classify the non-printable segments as critical or non-critical. Redesign of critical thin segments may include thickening the critical thin segments such that the segment size of the critical thin segments satisfy a thickening criterion with respect to the printer resolution and smoothing sharp corners added to the cross-sectional slice at an intersection between the critical thin segment and a neighboring printable segment. Redesign of the critical thin segments may account for tolerable overhang.
1. A method comprising:
accessing a three-dimensional (3D) model representative of an object to be constructed by a 3D printer;
extracting a cross-sectional slice of the 3D model perpendicular to a build direction for construction of the object by the 3D printer;
segmenting the cross-sectional slice into printable segments and non-printable segments, wherein the non-printable segments have a segment size smaller than a printer resolution of the 3D printer;
using a machine learning model trained using geometrical features computed on thin regions to classify each of the non-printable segments as a critical non-printable segment or a non-critical non-printable segment;
modifying the 3D model by thickening the critical non-printable segments such that the segment size of the critical non-printable segments satisfy a thickening criterion with respect to the printer resolution;
determining not to redesign the non-critical non-printable segments in the 3D model even though the non-critical non-printable segments have a segment size smaller than a printer resolution of the 3D printer; and
providing the modified 3D model to the 3D printer for construction of the object,
wherein the determining not to redesign the non-critical non-printable segments in the 3D model comprises including the non-critical non-printable segments in the modified 3D model.
2. The method of claim 1 , wherein thickening the critical non-printable segments comprises, for a given critical non-printable segment:
incrementally thickening the given critical non-printable segment with a dilation shape over a number of dilation iterations; and
incrementally increasing the thickening amount over successive dilation iterations based on a function of the number of iterations and the printer resolution.
3. The method of claim 1 , wherein modifying the 3D model further comprises, for a given critical non-printable segment:
identifying, at an intersection between the critical non-printable segment and a neighboring printable segment, a sharp corner added to the cross-sectional slice by the thickening; and
smoothing the sharp corner through curve interpolation.
4. The method of claim 1 , wherein modifying the 3D model by thickening the critical non-printable segments comprises, for a given critical non-printable segment:
modifying the 3D model by thickening the given critical thin-non-printable segment with an inverted conical thickening shape with a conical slant angle determined based on an allowable overhang parameter specified for construction of the object with the 3D printer.
5. The method of claim 4 , wherein the inverted conical thickening shape is 3D, has a reference point at a center of a cone base of the inverted conical thickening shape and the cone base has a diameter equal to a diameter associated with a 2D representation of the printer resolution.
6. The method of claim 4 , wherein modifying the 3D model by thickening the critical thin segments comprises, for the given critical non-printable segment, modifying a voxel representation of the 3D model by dilating the given critical non-printable segment with the inverted conical thickening shape; and
further comprising converting the modified voxel representation of the 3D model into a triangulated or CAD surface representation of the object.
7. A non-transitory machine-readable medium comprising instructions executable by a processor to:
access a three-dimensional (3D) model representative of an object to be constructed by a 3D printer;
extract a cross-sectional slice of the 3D model perpendicular to a build direction for construction of the object by the 3D printer;
segment the cross-sectional slice into printable segments and non-printable segments, wherein the non-printable segments have a segment size smaller than a printer resolution of the 3D printer;
classify each of the non-printable segments as a critical non-printable segment or a non-critical non-printable segment;
modify the 3D model by thickening the critical non-printable segments such that the segment size of the critical non-printable segments satisfy a thickening criterion with respect to the printer resolution;
determine not to redesign the non-critical non-printable segments in the 3D model even though the non-critical non-printable segments have a segment size smaller than a printer resolution of the 3D printer, wherein determination not to redesign the non-critical non-printable segments in the 3D model comprises modifying the 3D model to remove the non-critical non-printable segments; and
provide the modified 3D model to the 3D printer for construction of the object.
8. The non-transitory machine-readable medium of claim 7 , wherein the instructions executable to thicken the critical non-printable segments comprise instructions executable to, for a given critical non-printable segment:
incrementally thicken the given critical non-printable segment with a dilation shape over a number of dilation iterations; and
incrementally increase a size of the dilation shape over successive dilation iterations based on a function of the number of iterations and the printer resolution.
9. The non-transitory machine-readable medium of claim 7 , wherein the instructions further comprise instructions executable to smooth a sharp corner at an intersection between a given critical non-printable segment and a neighboring printable segment, including by:
identifying a region surrounding the sharp corner with a region size determined based on a factor of the printer resolution; and
applying a curve interpolation in the identified region surrounding the sharp corner to smooth the sharp corner.
10. The non-transitory machine-readable medium of claim 7 , wherein the thickening criterion is satisfied when the segment size of the thickened critical thin segments exceed a threshold percentage of the printer resolution.
11. The non-transitory machine-readable medium of claim 7 , wherein the instructions to modify the 3D model comprise instructions further to:
extend the cross-sectional slice by a slice height of the cross-sectional slice; and
merge the extended cross-sectional slice with other extended cross-sectional slices to form the modified 3D model.
12. A system comprising:
a thin segment identification engine configured to:
access a three-dimensional (3D) model representative of an object to be constructed by a 3D printer;
extract cross-sectional slices of the 3D model perpendicular to a build direction for construction of the object by the 3D printer;
segment the cross-sectional slices into printable segments and non-printable segments;
use machine learning model trained using geometrical features computed on thin regions to classify each of the non-printable segments as a critical non-printable segment or a non-critical non-printable segment; and
a thin segment redesign engine configured to:
modify the 3D model by thickening the critical non-printable segments such that the segment size of the critical non-printable segments satisfy a thickening criterion with respect to the printer resolution;
determine not to redesign the non-critical non-printable segments in the 3D model even though the non-critical non-printable segments have a segment size smaller than a printer resolution of the 3D printer, wherein the thin segment redesign engine is configured to determine not to redesign the non-critical non-printable segments in the 3D model by modifying the 3D model to remove the non-critical non-printable segments; and
provide the modified 3D model to the 3D printer for construction of the object.
13. The system of claim 12 , wherein the thin segment redesign engine is further configured to, after thickening the critical non-printable segments:
extend the cross-sectional slices by a slice height of the cross-sectional slices along the build direction, opposite the build direction, or along a combination of both; and
merge the extended cross-sectional slices to form the modified 3D model.
14. The system of claim 12 , wherein the thin segment redesign engine is configured to thicken the critical non-printable segments by, for a given critical non-printable segment:
incrementally thickening the given critical non-printable segment with a dilation shape over a number of dilation iterations; and
incrementally increasing a size of the dilation shape over successive dilation iterations based on a function of the number of iterations and the printer resolution.
15. The system of claim 12 , wherein the thin segment redesign engine is further configured to smooth a sharp corner at an intersection between a given critical non-printable segment and a neighboring printable segment, including by:
identifying a region surrounding the sharp corner with a region size determined based on a factor of the printer resolution; and
applying a curve interpolation in the identified region surrounding the sharp corner to smooth the sharp corner.
16. The system of claim 12 , wherein the thickening criterion is satisfied when the segment size of the thickened critical thin segments exceed a threshold percentage of the printer resolution.
17. The system of claim 12 , wherein the thin segment redesign engine is configured to thicken the critical non-printable segments with an inverted conical thickening shape with a conical slant angle determined based on an allowable overhang parameter specified for construction of the object with the 3D printer.
18. The system of claim 17 , wherein the inverted conical thickening shape is 3D, has a reference point at a center of a cone base of the inverted conical thickening shape and the cone base has a diameter equal to a diameter associated with a 2D representation of the printer resolution.