Adaptive Point Density for Global Illumination Rendering

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Solution Overview

Problem

Current point-based global illumination techniques require high computational resources and memory due to the need for dense point clouds, especially when rendering scenes with objects both in-view and out-of-view from the main camera, leading to inefficient rendering times and unnecessary point density adjustments.

Innovation Solution

The method determines a desired point area for points in a point cloud based on the sample location distance and solid angle in camera space, allowing for adaptive point density adjustments to ensure proper surface coverage while reducing the number of points needed, particularly by using different point areas and densities for in-view and out-of-view objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high point density is used to ensure proper surface coverage for both in-view and out-of-view objects, then rendering fidelity is improved, but computational complexity and memory requirements increase

Engineering Contradiction:
Improverendering fidelityVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating point density requirements between in-view and out-of-view objects. Points representing in-view objects are generated with higher density (smaller desired point area) while points for out-of-view objects use lower density (larger desired point area). This spatially varying point density maintains rendering fidelity where needed while reducing computational complexity elsewhere.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of point area based on object visibility. The desired point area is dynamically adjusted according to whether the surface primitive is in-view or out-of-view, allowing the system to adapt point density to rendering requirements rather than using a uniform density throughout the scene.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high point density is used for out-of-view objects to ensure proper indirect illumination, then lighting accuracy is improved, but memory requirements increase

Engineering Contradiction:
Improvelighting accuracyVSAvoidmemory requirements
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by assigning different point density characteristics to in-view and out-of-view objects. Out-of-view objects use larger desired point areas, providing sufficient lighting accuracy for indirect illumination while occupying less memory space compared to uniform high-density point clouds.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If uniform point density is used throughout the scene, then implementation simplicity is maintained, but rendering efficiency decreases

Engineering Contradiction:
Improveimplementation simplicityVSAvoidrendering efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent implements local quality through a visibility-based classification system that separates in-view and out-of-view objects. This approach maintains relative implementation simplicity by using a clear binary classification while achieving significant rendering efficiency improvements through adaptive point density.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the point area parameter based on visibility status, allowing the system to optimize rendering efficiency by using smaller point areas for in-view objects and larger point areas for out-of-view objects, rather than maintaining uniform density throughout.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9508191B2Optimal point density using camera proximity for point-based global illumination
Publication Date: 2016.11.29 DREAMWORKS ANIMATION LLC
  • US9508191B2 patent drawing
  • US9508191B2 patent drawing
  • US9508191B2 patent drawing

AI summary

A computer-animated scene is shaded using a point in a point cloud. The point represents a sample location on a surface primitive of an object in the scene. The surface primitive lies at least partially within a camera viewing frustum of a virtual camera, which has a focal point. A sample location distance, which is a near plane distance of the camera viewing frustum or the length of a line between the sample location on the surface primitive and the focal point of the virtual camera, is determined. A solid angle of the surface primitive subtended at the focal point of the virtual camera is obtained. A desired point area of the point in the point cloud is determined based on the sample location distance and the solid angle. The scene is shaded using the desired point area of the point in the point cloud.