Subsurface Scattering Optimization via Octree Pre-calculation
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Solution Overview
Problem
Current methods for rendering realistic 3D images struggle with computational efficiency in modeling subsurface scattering, particularly for translucent materials, leading to increased rendering times and resource utilization.
Innovation Solution
A method that distributes sample points across a 3D object model, constructs an octree data structure, and selectively uses previously or newly determined subsurface scattering contributions based on solid angles and luminosity functions to accelerate subsurface scattering calculations, optimizing memory usage and computational performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional subsurface scattering calculations are performed for all sample points, then rendering quality is improved, but computational time and resource utilization increase significantly
Solution Approach 1:
The patent pre-calculates and stores subsurface scattering contributions for a subset of sample points before the main rendering pass. This preliminary computation allows the final rendering to reuse these pre-determined values, significantly reducing the computational time during the actual rendering process while maintaining rendering quality.
Solution Approach 2:
The patent applies different computational strategies to different regions of the 3D object based on local characteristics. By using the solid angle criterion to identify which sample points require full calculation versus which can use pre-determined values, the system optimizes computational resources locally rather than applying a uniform approach across the entire object.
2Measurement precision
If subsurface scattering is calculated for every sample point, then accuracy is improved, but device complexity and resource utilization worsen
Solution Approach 1:
The system performs preliminary subsurface scattering calculations for a representative subset of sample points and stores these results in a data structure (such as an octree). During the main rendering pass, these pre-computed values are reused, reducing the need for complex real-time calculations and lowering overall device resource utilization.
Solution Approach 2:
The patent creates a hierarchical data structure (octree) that organizes and stores pre-computed subsurface scattering contributions. This structured copy of scattering data can be efficiently queried and reused during rendering, avoiding the need to perform complex calculations repeatedly for the same or similar sample points.
3Measurement precision
If full subsurface scattering calculation is performed, then image quality is improved, but productivity decreases
Solution Approach 1:
By pre-calculating subsurface scattering contributions for a subset of sample points and storing them in an optimized data structure, the system enables faster rendering in the main pass. This preliminary preparation trades some initial computational effort for significantly improved rendering speed during actual image generation.
Solution Approach 2:
The patent uses the solid angle criterion to selectively apply full subsurface scattering calculations only where necessary (when solid angle exceeds threshold), while using pre-determined values elsewhere. This localized approach maintains image quality in critical areas while improving overall rendering productivity.
Data Source
AI summary
The present disclosure includes, among other things, systems, methods, and program products for estimating radiant exitance due to subsurface scattering. For example, one or more aspects of the subject matter described in this disclosure can be embodied in one or more methods that include distributing a plurality of sample points across the surface of a 3D object model to be rendered into a 2D image and determining a solid angle subtended by a first sample point and a second sample point relative to a region on the 3D object model. Depending on the determined solid angle relative to a threshold value, a previously determined subsurface scattering contribution for the region or a newly determined subsurface scattering contribution for the region may selectively be used for rendering a portion of the 2D image.