3D Part Iso-Surface Reconstruction for Unambiguous Additive Manufacturing
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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 converts a surface representation of a 3D part into a volume representation using an unsigned distance field and flood filling, ensuring unambiguous delimitations by propagating labels until a gradient inversion is reached, and then inverting distance values to obtain a signed distance field for accurate iso-surface computation and printing.
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 become ambiguous when surfaces contain holes, are non-manifold or intersect
Solution Approach 1:
The patent introduces a volume representation as an intermediary between the surface representation and the final 3D object. The volume representation with labeled voxels serves as a mediator that resolves the ambiguity of surface delimitations while preserving the geometric precision of the original surface model. This intermediary step allows the system to handle complex geometries with holes and intersections without losing the unambiguity of region delimitations.
2Reliability
If volume representation is used for 3D object, then delimitations are unambiguous, but memory footprint increases significantly
Solution Approach 1:
The patent applies partial action by labeling only the necessary voxels that are required to define the delimitations unambiguously. Instead of requiring a complete and exhaustive volume representation of the entire 3D space, the method labels only the voxels that contribute to defining the boundaries between different regions. This partial labeling approach maintains the unambiguity of delimitations while significantly reducing the memory footprint compared to a full volume representation.
3Reliability
If flood filling is performed without stopping condition, then label propagation is complete, but computational resources are wasted
Solution Approach 1:
The patent implements a feedback mechanism through the gradient inversion stopping condition. During the flood filling process, the algorithm continuously monitors the gradient of the distance field and compares it with the propagation direction. When a gradient inversion is detected, the algorithm receives feedback that the label propagation has reached its boundary and should stop. This feedback-based stopping condition ensures complete label propagation for all necessary regions while preventing unnecessary propagation into already-labeled or irrelevant areas, thus optimizing computational efficiency.
Data Source
AI summary
Described is a computer-implemented method of additive manufacturing of a three-dimensional part. The method includes obtaining a surface representation of a 3D part in a 3D scene, the surface representation being enclosed inside a bounding volume, discretizing the scene into voxels, forming an unsigned distance field by storing a minimal distance value to the surface representation of the 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 unlabeled voxels so as to obtain a signed distance field, computing an iso-surface of the part at iso-value zero based on the signed distance field, and additive manufacturing the part.