3D Shape Data Editing Using Signed Distance Fields
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Solution Overview
Problem
Existing methods for representing three-dimensional shapes using three-dimensional elements struggle to accurately maintain smooth curved surfaces, leading to discrepancies between the original shape and the edited shape, especially when converting between voxel-based and polygon-based representations.
Innovation Solution
A three-dimensional shape data editing apparatus that converts three-dimensional shape data from voxel-based to polygon-based representations by dividing the coordinate space into regions, determining interference using signed distance fields, and arranging voxels and polygons to maintain the original shape's integrity during deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If three-dimensional shape data is represented by combining three-dimensional elements (voxels), then the data structure is simplified and easier to manipulate, but the ability to accurately represent smooth curved surfaces deteriorates
Solution Approach 1:
The patent introduces signed distance fields as an intermediary data structure between voxel-based and polygon-based representations. The signed distance field stores distance information from each voxel to the object surface, enabling accurate curved surface representation while maintaining the simplicity of voxel manipulation. This intermediary allows conversion to high-precision polygon models when needed.
Solution Approach 2:
The patent changes the parameter representation by storing not just presence/absence of voxels but also signed distance values. This parameter enrichment allows the same voxel grid to represent both simple binary occupancy and precise continuous distance information, resolving the contradiction between simplicity and accuracy.
2Ease of operation
If three-dimensional shape data configured by three-dimensional elements is edited, then the editing process is simplified, but the shape deviates from the original three-dimensional shape
Solution Approach 1:
The patent implements feedback by continuously maintaining signed distance field information during editing operations. When voxels are added or removed, the signed distance values are updated to reflect the current state, providing continuous feedback that guides accurate shape reconstruction and ensures fidelity to the intended design.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing signed distance values for all voxels before editing begins. This preliminary information serves as a reference during editing, allowing the system to maintain shape accuracy even as the voxel configuration changes.
3Ease of manufacture
If marching cubes method is used to convert voxel data to polygon data, then the conversion process is straightforward, but the resulting shape differs from the original object's curved surfaces
Solution Approach 1:
The patent changes the parameters used in surface generation from simple voxel center intersections (marching cubes) to signed distance field contours. By using the stored distance values to guide polygon placement and orientation, the method maintains conversion simplicity while dramatically improving curved surface accuracy.
Solution Approach 2:
The patent creates a more accurate copy of the original object's surface by using signed distance fields to guide polygon generation. Instead of copying the approximate stepped surface from marching cubes, the system copies the precise curved surface geometry encoded in the distance field information.
Data Source
AI summary
A three-dimensional shape data editing apparatus includes a processor configured to set, based on three-dimensional shape data of a surface of a three-dimensional shape of an object configured by using a formation surface of at least one of plural flat surfaces or curved surfaces, for each of plural divided three-dimensional regions, a distance from a predetermined location of the region to the formation surface of the three-dimensional shape of the object configured by the formation surface.