Parametric Skin Surface for Computer Character Decoration

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Solution Overview

Problem

Current animation technologies face challenges in realistically animating characters with surface-attached features like hairs, fur, scales, and feathers, particularly in depicting a large number of feathers in relation to a skin surface, due to the complexity of visualizing and simulating these features in conjunction with the skin surface.

Innovation Solution

The method involves defining a skin surface using connected parametric surfaces, placing guide locations and feature locations, partitioning the skin surface into cells, and determining interpolation weights to accurately position and render surface-attached features such as feathers, using techniques like parallel transport frames to construct the geometry of features like feathers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large number of feathers are modeled to cover the skin surface, then the realism of the animation is improved, but the computational complexity and rendering time increase significantly

Engineering Contradiction:
ImproverealismVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The skin surface is divided into multiple cells, and feathers are distributed across these cells. Each cell contains a subset of feathers, allowing the system to manage complexity locally rather than globally. This segmentation enables realistic feather distribution while reducing computational burden by processing smaller, manageable portions of the surface simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the skin surface are treated differently based on their local characteristics. The system determines interpolation weights and feather placement locally within each cell, allowing for varied feather density and orientation in different body regions. This local quality approach maintains realism in visible areas while reducing complexity in less critical regions.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If feathers are densely distributed across the skin surface, then the visual accuracy is improved, but the memory requirements and processing time increase

Engineering Contradiction:
Improvevisual accuracyVSAvoidnumber of feathers
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The skin surface is partitioned into cells, and feathers are strategically placed within each cell based on local requirements. This segmentation allows the system to achieve high visual accuracy in critical regions while reducing the total number of feathers in less visible areas, thereby balancing visual quality with computational efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses interpolation weights to smoothly vary feather properties across the skin surface. By changing parameters such as feather density, orientation, and size through interpolation rather than uniform distribution, the system achieves high visual accuracy with a reduced total number of feathers, optimizing the trade-off between visual quality and computational cost.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the skin surface is divided into multiple cells for feature placement, then the placement precision is improved, but the algorithm complexity increases

Engineering Contradiction:
Improveplacement precisionVSAvoidalgorithm complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The skin surface is segmented into cells, which simplifies the placement algorithm by breaking down the complex task of distributing feathers across the entire surface into smaller, more manageable sub-tasks within each cell. This segmentation actually reduces algorithmic complexity while improving placement precision through localized control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The skin surface is pre-partitioned into cells before feather placement begins. This preliminary action establishes a structured framework that guides subsequent feather placement operations, making the algorithm more systematic and easier to implement while achieving precise feather distribution across the surface.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP1986158B1Decorating computer generated character with surface attached features
Publication Date: 2019.10.30 DREAMWORKS ANIMATION LLC
  • EP1986158B1 patent drawingFigure 1~2
  • EP1986158B1 patent drawingFigure 3
  • EP1986158B1 patent drawingFigure 4

AI summary

A computer generated character is decorated with skin-attached features in computer graphics by defining a skin surface of the computer generated character. The skin surface is defined using a set of one or more connected parametric surfaces. Feature locations for the features are placed on the defined skin surface. Guide locations for guides are placed on the defined skin surface. The skin surface is partitioned into a plurality of cells. Each cell has a set of vertices. The set of vertices for each cell is a set of the guide locations. Interpolation weights are determined for the feature locations using the guide locations and the plurality of cells.