Procedural Microstructure Modeling for Dynamic Skin Animation

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Solution Overview

Problem

Current methods for generating realistic computer-animated outer surfaces, such as skin, struggle to accurately represent microstructures like pores and wrinkles, especially when they change shape during motion, due to limitations in texture-based displacement mapping techniques.

Innovation Solution

The use of procedural modeling to generate microstructures, where a grooming processor creates a procedural model of the skin's microstructures, allowing for detailed control over their appearance and location through microstructure parameter values, and an adaptive mesh is generated to include these features, optimized for finite-element simulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If texture-based displacement mapping techniques are used to represent microstructures, then the implementation is simple and fast, but the control over appearance is limited and microstructures cannot accurately represent dynamic changes

Engineering Contradiction:
Improveease of implementationVSAvoidcontrol over appearance
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces texture-based displacement mapping (a surface painting technique) with a mechanical simulation approach using finite element analysis. Instead of applying 2D textures to a 3D surface, the system creates a volumetric mesh representing skin layers and applies mechanical forces to simulate how microstructures deform during motion, providing both artistic control and physical accuracy

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces multiple controllable parameters including microstructure size, spacing, depth, density, and deformation characteristics. Artists can adjust these parameters to control the appearance and behavior of microstructures, enabling precise control over how pores, wrinkles, and other skin details respond to motion and facial expressions

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If conventional texture-based displacement mapping techniques are used, then computational cost is low, but the ability to represent dynamic microstructure changes during motion is insufficient

Engineering Contradiction:
Improvecomputational costVSAvoidability to represent dynamic changes
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent divides the skin into multiple volumetric layers (epidermis, dermis, subcutaneous tissue) with a mesh of elements that can independently deform. This segmentation allows different regions and depths of the skin to respond differently to forces, enabling realistic simulation of how microstructures change during motion while maintaining computational efficiency through hierarchical modeling

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic simulation system where the microstructure mesh responds to applied forces in real-time. The finite element model calculates deformations based on material properties and applied loads, allowing microstructures to naturally adapt their shape and position during motion, facial expressions, and interactions with the environment

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If high-resolution mesh is used to capture microstructures, then detail accuracy is improved, but computational complexity and processing time increase significantly

Engineering Contradiction:
Improvedetail accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local refinement to the volumetric mesh, creating high-resolution regions only where microstructures are present (such as the facial surface) while using coarser resolution in deeper tissue layers and less critical areas. This allows detailed representation of visible microstructures while reducing overall computational complexity through adaptive mesh refinement

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent focuses computational resources on simulating only the visible microstructures that affect appearance (pores, wrinkles, furrows on the skin surface) rather than modeling every cellular detail throughout the entire skin volume. This partial modeling approach provides sufficient visual fidelity while keeping computational costs manageable

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3980975B1Method of inferring microdetail on skin animation
Publication Date: 2022.11.23 WETA DIGITAL LTD
  • EP3980975B1 patent drawingFigure 1
  • EP3980975B1 patent drawingFigure 2
  • EP3980975B1 patent drawingFigure 3

AI summary

A computer-implemented method and system for modeling an outer surface, such as skin. The method includes, under the control of one or more computer systems configured with executable instructions, defining a plurality of microstructures such as microstructures to be displayed in microstructure locations on a geometric model of a character or inanimate object, and generating a volumetric mesh including the plurality of microstructures. The volumetric mesh is configured to be applied to the geometric model as an outer surface (e.g., skin) covering the geometric model.