3D Part Surface-to-Volume Conversion for Watertight Printing
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Solution Overview
Problem
Current additive manufacturing methods face challenges in handling ambiguous 3D object representations, particularly in maintaining unambiguous delimitations between volume regions, which can lead to incorrect printing and material wastage due to non-manifold or intersecting surfaces.
Innovation Solution
A computer-implemented method that transforms a surface representation of a 3D part into a signed distance field using flood filling, allowing for the propagation of labels and inversion of distance values to create a watertight mesh, enabling accurate representation and printing of complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If surface representation is used for 3D object, then memory footprint is low and precision is high, but delimitations between regions become ambiguous when surface contains holes, non-manifold or intersecting surfaces
Solution Approach 1:
The patent introduces a volumetric representation as an intermediary between the surface representation and the final manufacturing data. This volume representation explicitly defines inside/outside regions, resolving the ambiguity problem while maintaining efficiency through optimized data structures and processing methods.
Solution Approach 2:
The patent transitions from a 2D surface representation to a 3D volumetric representation. By adding the dimensional aspect of volume, the system can explicitly define region delimitations and resolve ambiguities that exist in surface-only representations, particularly for complex geometries with holes or intersections.
2Reliability
If volume representation is used for 3D object, then delimitations between regions are unambiguous, but memory footprint becomes much higher
Solution Approach 1:
The patent changes the representation parameters by using a volumetric data structure with optimized memory allocation. Instead of storing complete volumetric data for the entire object, the system uses a hierarchical or sparse representation that reduces memory footprint while maintaining the unambiguous region delimitation capability of volume representations.
3Ease of manufacture
If traditional methods are used to handle ambiguous surfaces, then manufacturing process is simple, but material wastage occurs due to incorrect printing interpretation
Solution Approach 1:
The patent performs preliminary processing of the 3D model data before manufacturing, including validation of surface watertightness, resolution of ambiguities, and generation of corrected volumetric representations. This preliminary action prevents material wastage during printing by ensuring the model is correctly interpreted before the manufacturing process begins.
Data Source
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AI summary
The invention notably relates to a computer-implemented method of additive manufacturing of a three-dimensional (3D) part. The method comprises providing a surface representation of a 3D part in a 3D scene, the surface representation being enclosed inside a bounding volume; discretizing the 3D scene into voxels; forming an unsigned distance field by storing a minimal distance value to the surface representation of the 3D part for each voxel; determining one or more voxels located outside the bounding volume, the one or more voxels located outside the bounding volume being associated with a label; propagating by flood filling the label until a stopping condition is met, which is reaching a gradient inversion of the distance field; inverting the sign of the distance value of all unlabelled voxels so as to obtain a signed distance field; computing an iso-surface of the 3D part at iso-value zero based on the signed distance field; and additive manufacturing the 3D part.