Dynamic Soft Shadow Generation for Concave 3D Objects
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Solution Overview
Problem
Existing methods for generating shadow effects in three-dimensional graphics are computationally intensive and unsuitable for low-power devices, particularly failing to accurately render shadows for concave objects and adjust shadows based on light source positions.
Innovation Solution
A method that identifies both convex and concave object shapes to generate soft shadow maps, modifying these maps based on light source positions, using a processor to create a concave hull and soft shadow mesh, and applying lighting textures to depict realistic shadows that change with light source movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow volumes and shadow maps are used to generate shadow effects, then shadow realism is improved, but computational complexity increases making them unsuitable for low power embedded devices
Solution Approach 1:
The patent uses simple 2D shadow polygons instead of complex 3D shadow volumes. These shadow polygons are computationally inexpensive to generate and update, providing adequate shadow effects for mobile devices with limited processing power while maintaining acceptable visual quality.
Solution Approach 2:
The patent extracts only the essential shadow-casting geometry (convex and concave hulls) from the full 3D object model, generating shadow effects from 2D projections rather than complete 3D volume calculations. This extraction reduces computational requirements while preserving shadow accuracy.
2Productivity
If convex hull method is used to generate shadow polygons, then processing speed is improved, but shadow accuracy deteriorates for concave objects
Solution Approach 1:
The patent segments the shadow generation process into two distinct parts: convex hull generation for fast processing and concave hull generation for accurate concave object shadows. This segmentation allows the system to use the appropriate method for each object type, maintaining both speed and accuracy.
Solution Approach 2:
The patent dynamically selects between convex and concave hull methods based on the object geometry. The system automatically determines whether an object requires concave hull processing by analyzing its footprint geometry, switching methods as needed to maintain accuracy without sacrificing processing efficiency for simple convex objects.
3Device complexity
If static shadow maps are generated, then computational load is reduced, but shadow realism deteriorates as shadows do not respond to light source movement
Solution Approach 1:
The patent implements dynamic shadow polygons that automatically update their position and shape in response to changes in light source location. As the light source moves in the 3D scene, the shadow polygons are recalculated to reflect the new shadow positions, maintaining realism while using computationally efficient 2D projections.
Solution Approach 2:
The patent pre-calculates the convex and concave hulls of objects during the modeling phase, storing these geometric properties for rapid shadow generation during runtime. This preliminary preparation allows the system to quickly generate accurate shadows without performing complex calculations during rendering, reducing real-time computational load.
Data Source
AI summary
A method of generating three-dimensional graphics enables the generation of performance and quality balanced sun position sensitive soft shadows for objects including three-dimensional models of buildings. The method includes identification of both convex and concave object shapes for the generation of the soft shadow meshes and the modification of the soft shadow meshes based on the position of a light source in a three-dimensional virtual environment to generate realistic shadow graphics including shadows that change shape in response to movement of the light source.