Shadow Mesh Generation With Constrained Edge Collapse
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Solution Overview
Problem
The generation of shadow meshes for rendering shadows in 3D graphics applications is tedious and difficult due to the need to avoid overshadowing, where the shadow mesh extends outside the associated graphics mesh, and existing LODs are not a reliable choice for this purpose.
Innovation Solution
A method is provided to generate shadow meshes by performing edge collapse operations on components of a graphics mesh, constraining new vertices to be within the planes of adjacent faces, and using an optimization algorithm to select shadow versions that meet a polygon budget while optimizing visual fidelity, ensuring the shadow mesh does not overshadow the graphics mesh.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hand-authoring a shadow mesh to avoid overshadowing, then shadow rendering accuracy is improved, but authoring time and complexity increase
Solution Approach 1:
The patent creates a shadow mesh by copying the vertex data from the original graphics mesh and then systematically simplifying it through edge collapse operations. This automated copying and simplification process replaces manual hand-authoring, significantly reducing authoring time while maintaining accuracy through algorithmic control of the simplification process.
Solution Approach 2:
The system performs self-service by automatically generating the shadow mesh from the original graphics mesh without requiring manual artist intervention. The edge collapse algorithm automatically selects edges to collapse and computes new vertex positions, making the entire shadow mesh generation process autonomous and eliminating the time-consuming manual authoring step.
2Loss of time
If using automatically generated LOD mesh as shadow mesh, then authoring time is reduced, but shadow accuracy deteriorates due to overshadowing
Solution Approach 1:
The patent applies local quality by treating each component of the mesh independently during the edge collapse process. Each component's shadow version is generated with specific constraints tailored to its local geometry, ensuring that the shadow mesh accurately represents the local features that matter for shadow casting while maintaining overall accuracy.
Solution Approach 2:
The system performs preliminary action by pre-computing the shadow mesh with guaranteed geometric constraints before rendering. The edge collapse operations are performed in advance with built-in constraints that prevent vertices from extending outside the original mesh boundaries, eliminating overshadowing issues that would require post-processing correction.
3Productivity
If simplifying shadow mesh to reduce polygon count, then rendering performance is improved, but visual fidelity decreases
Solution Approach 1:
The patent applies dynamics by generating multiple versions of the shadow mesh with different levels of simplification (different polygon counts). This creates a dynamic system where the appropriate shadow mesh version can be selected based on the required rendering performance and visual fidelity requirements, allowing flexible adaptation to different runtime conditions.
Solution Approach 2:
The system changes parameters by systematically varying the level of edge collapse applied to generate different versions of the shadow mesh. By controlling the number of edge collapse operations and the criteria for selecting edges to collapse, the system can adjust the polygon count and visual fidelity parameters to match specific performance requirements.
4Reliability
If ensuring shadow mesh stays inside graphics mesh boundary, then overshadowing is avoided, but generation complexity increases
Solution Approach 1:
The patent performs preliminary action by establishing geometric constraints at the beginning of the edge collapse process. The algorithm pre-computes the planes of adjacent faces and uses these planes as constraints during vertex position computation, ensuring that new vertices remain inside the original mesh boundary from the start, thereby avoiding overshadowing without requiring complex post-processing.
Solution Approach 2:
The system replaces complex manual geometric constraint management with an automated computational mechanism. The edge collapse algorithm uses mathematical computations to automatically enforce geometric constraints, substituting manual artistic judgment and complex geometric reasoning with a systematic computational approach that is more reliable and easier to implement.
Data Source
AI summary
A method, device, and computer-readable storage medium for generating a shadow mesh. The method includes: receiving a graphics mesh; computing a set of LOD versions for each component of the graphics mesh, where each successive LOD version in the set of LOD versions includes fewer polygons than the preceding LOD version; computing a set of shadow versions for each component of the graphics mesh, where each successive shadow version in the set of shadow versions includes fewer polygons than the preceding shadow version, and each successive shadow version includes vertices that lie within a mesh defined by the preceding shadow version; generate N LOD meshes for the graphics mesh by selecting, for each LOD, a LOD version of each component to include in the LOD mesh; and generating a shadow mesh by selecting a shadow version of each component to include in the shadow mesh.