Fact-checked by Grok 2 weeks ago

Skeletal animation

Skeletal animation is a technique in computer graphics for animating three-dimensional models, particularly characters and articulated objects, by representing them with a deformable surface mesh bound to an internal hierarchical skeleton of rigid bones. The bones form a tree-like structure where each bone can be transformed (translated, rotated, or scaled), and the mesh vertices are weighted to one or more bones, causing the mesh to deform smoothly as the skeleton moves. This approach enables efficient simulation of natural movements, such as walking or gesturing, by leveraging the skeleton's jointed nature rather than animating individual vertices directly.^[1]^[2] The core mechanism of skeletal animation relies on skinning, where the mesh is "skinned" to the skeleton through vertex weights that determine each vertex's influence from nearby bones. A common method is linear blend skinning (LBS), in which a vertex's final position is computed as a weighted sum of the transformations applied by its influencing bones, typically up to four per vertex for hardware efficiency. Bone hierarchies ensure coordinated motion—for instance, rotating an upper arm bone propagates to the forearm and hand unless overridden—while techniques like inverse kinematics can automate realistic posing by solving for bone orientations based on end-effector targets. Rigging, the process of creating and binding the skeleton to the mesh, often involves artist-defined bone placement and weight painting to avoid artifacts like mesh collapsing at joints.^[2]^[1] Skeletal animation has become a cornerstone of modern digital content creation due to its computational efficiency and versatility, supporting real-time rendering in video games via GPU-accelerated skinning and enabling complex film animations through integration with motion capture data. It is widely implemented in industry tools like Unity's Skinned Mesh Renderer, which handles up to 32 influential bones per vertex for deformable meshes,^[3] and Valve's Source engine for simulating jointed entities from characters to machinery.^[1] Despite its advantages, challenges include the "candy wrapper" artifact in LBS during extreme poses, addressed by advanced variants like dual quaternion skinning.^[4]^[5] The technique originated in 1988 with joint-dependent local deformations introduced by Nadia Magnenat Thalmann, Richard Laperrière, and Daniel Thalmann as part of early efforts in physically based character modeling.^[6]^[1]^[2]

Introduction

Definition and Fundamentals

Skeletal animation is a technique in computer graphics for deforming a 3D model, typically represented as a mesh or skin, through an underlying hierarchical skeleton composed of interconnected bones and joints.^[7] This approach allows for realistic movement of articulated objects, such as characters, by simulating how forces propagate through a structure similar to a biological skeleton.^[8] Unlike direct manipulation of the entire mesh, the skeleton serves as an invisible armature that controls the positioning and deformation of the visible geometry.^[9] Key components include bones, which are rigid segments defining the structural elements, and joints, which act as rotation points connecting the bones and enabling degrees of freedom (typically 1 to 6 per joint) for movement.^[8] The hierarchy organizes these elements in a tree-like structure with parent-child relationships, where transformations applied to a parent bone propagate to its children, ensuring coordinated motion across the model.^[7] For instance, in a humanoid skeleton, the root joint might be at the pelvis, with child branches extending to the spine, arms, and legs, allowing complex poses like walking or gesturing.^[8] A typical humanoid model may feature 20 to 100 joints to capture detailed articulation.^[8] The overall pipeline consists of three high-level stages: rigging, where the skeleton is constructed and attached to the mesh; skinning, where vertices of the mesh are bound to bones via influence weights; and animation, where time-varying transformations are applied to the bones to drive the deformation.^[7] This process enables efficient real-time rendering, particularly in applications requiring dynamic character movement.^[7] In comparison to alternative methods, skeletal animation emphasizes articulated deformation through hierarchical control, differing from vertex animation (also known as per-vertex or morph target animation), which precomputes and interpolates positions directly on mesh vertices without a skeleton, making it suitable for simpler or localized changes like facial expressions but less scalable for complex, full-body motions due to higher memory demands.^[10] Similarly, it contrasts with sprite sheets, a 2D technique using sequences of pre-drawn frames for flipbook-style animation, which lacks dynamic deformation and relies on static images rather than bone-driven articulation.^[11]

Historical Development

The roots of skeletal animation trace back to traditional stop-motion and frame-by-frame animation techniques in the early 20th century, where physical armatures—metal skeletons with ball-and-socket joints—were used to support and manipulate puppets, allowing animators to create lifelike movements by incrementally adjusting poses between frames.^[12] These armatures provided a rigid yet flexible internal structure, enabling precise control over character deformation, much like the digital bones in modern systems, and were pivotal in pioneering works by animators such as Willis O'Brien in films like The Lost World (1925).^[12] The formal emergence of skeletal animation in computer graphics occurred in the 1980s, as researchers sought to digitize articulated figure animation for more efficient simulation of human-like movements. In 1988, Nadia Magnenat Thalmann, Richard Laperrière, and Daniel Thalmann introduced key concepts in joint-dependent local deformations, enabling realistic soft object animation through hierarchical bone structures and inverse kinematics, as detailed in their seminal paper "Joint-Dependent Local Deformations for Hand Animation and Object Grasping."^[13] This approach laid the groundwork for computational skeletons that could deform meshes dynamically, transitioning from manual keyframing to algorithmic control in academic and early software prototypes. Key developments accelerated in the 1990s with the integration of skeletal animation into commercial software, democratizing its use in professional production. Autodesk's 3D Studio MAX (released in 1996) incorporated bone hierarchies and inverse kinematics solvers, allowing animators to rig and animate complex characters efficiently for both games and films.^[14] Similarly, Autodesk Maya, launched in 1998, built on these foundations with advanced rigging tools that supported multi-layered skeletons and deformation blending, rapidly becoming a standard for high-end visual effects workflows.^[15] These tools marked a shift from experimental research to industry adoption, enabling scalable animation pipelines.^[16] The late 1990s and 2000s saw skeletal animation boosted by motion capture technology, which captured real human movements and mapped them onto digital skeletons for heightened realism. A landmark example was the 1993 film Jurassic Park, where Industrial Light & Magic (ILM) used early motion capture data—combined with keyframe animation on skeletal rigs—to drive dinosaur models, blending CGI with live-action in groundbreaking sequences like the T. rex pursuit.^[17] This integration of optical and magnetic capture systems onto hierarchical bones revolutionized character animation, reducing manual labor while enhancing fluidity, and influenced subsequent blockbusters like Titanic (1997).^[17] In the modern era from the 2010s to the 2020s, advancements in real-time rendering engines have transformed skeletal animation for interactive media, emphasizing performance and accessibility. Game engines like Unity (with its Mecanim system introduced in 2012) and Unreal Engine (featuring advanced skeletal mesh support since version 4 in 2014) optimized bone hierarchies for GPU-accelerated deformation, enabling seamless playback of complex animations at 60 frames per second.^[16] Open-source tools such as Blender, which evolved its armature system through versions like 2.8 in 2019, further lowered barriers by providing free, robust rigging for indie creators and studios alike.^[16] These innovations have extended skeletal animation's reach, supporting procedural blending and physics integration in real-time applications.^[16]

Technical Implementation

Skeleton Rigging

Skeleton rigging is the foundational process in skeletal animation where a hierarchical skeleton is constructed within a 3D model to enable articulated movement. This involves strategically placing bones along the model's geometry, often aligned with key anatomical or structural features such as limbs, torso, or mechanical joints. Joint locations are defined at bone endpoints, acting as pivot points that facilitate rotation and translation while maintaining structural integrity. The hierarchy is then established through parent-child relationships, ensuring that transformations propagate logically—for instance, motion applied to an upper arm bone influences the connected forearm and hand bones.^[18]^[19]^[20] Bone structures vary by model type to accommodate different forms of motion. Humanoid rigs typically employ a bipedal hierarchy with dedicated chains for the spine, arms, and legs, promoting natural upright locomotion. Quadruped configurations extend this by incorporating four limb chains connected to a central torso, suitable for animal characters. Custom rigs for non-organic entities, such as robots, utilize modular bone arrangements that reflect mechanical linkages rather than biological anatomy.^[21]^[20] Rigging tools in professional software, including Autodesk Maya and Blender, support precise bone placement and hierarchy building through features like joint orientation tools and constraint systems. Constraints, such as ball-and-socket setups for shoulders or hinge limits for elbows, restrict movement to realistic ranges and prevent unnatural distortions. The process concludes with setting an initial bind pose, commonly an A-pose or T-pose, which positions the model with arms extended to optimize joint alignment and prepare for subsequent mesh attachment. Pivot points must be carefully positioned to serve as accurate rotation centers, influencing the overall fidelity of deformations.^[21]^[18] Common challenges in skeleton rigging include achieving anatomical accuracy, especially in models with irregular geometries where bone placement must balance detail and simplicity. Scalability is another concern, as highly complex rigs with numerous bones can lead to redundant structures or control difficulties, necessitating iterative refinement to eliminate overestimation in joint positioning. For example, rigging a character's spine often incorporates 3 to 5 vertebrae bones to provide sufficient flexibility for torso bending and twisting while avoiding excessive segmentation.^[22]^[23]

Mesh Skinning and Binding

Mesh skinning, also known as binding, is the process of associating the vertices of a 3D visual mesh with the bones of a rigged skeleton to enable realistic deformations during animation. This linkage is typically achieved through linear blend skinning (LBS), a foundational technique where each vertex is influenced by one or more bones via non-negative weights that sum to 1, ensuring the deformed position is a convex combination of the bone transformations applied to the vertex's rest pose.^[24] LBS, originally conceptualized in early work on joint-dependent local deformations, computes the new vertex position as a weighted sum of transformations from the influencing bones.^[25] The skinning process begins with vertex weighting, where artists manually paint weights on the mesh surface using tools in software like Autodesk Maya or Blender to define how much each bone affects nearby vertices, or employ automatic algorithms that assign weights based on geodesic distances or heat diffusion from bones to vertices. For instance, at an elbow joint, vertices near the joint receive blended weights from both the upper arm and forearm bones, allowing smooth bending without abrupt seams. Typically, to maintain computational efficiency, each vertex is limited to a small number of influencing bones, often four, with the transformations blended linearly. The resulting deformed vertex position v' in world space is given by

v' = \sum_{i=1}^{n} w_i \cdot T_i(v),

where v is the rest-pose vertex position, w_i are the normalized weights for the n influencing bones, and T_i are the affine transformation matrices for those bones relative to the rest pose.^[24]^[26] Skinning techniques vary in complexity to balance realism and performance. Rigid skinning assigns each vertex to exactly one bone, resulting in piecewise rigid deformations suitable for simple props but prone to discontinuities at joints. Smooth skinning, embodied by LBS, uses blended weights for more natural transitions but introduces artifacts such as collapsing or stretching during extreme poses, including the "candy-wrapper" effect—a twisting collapse observed in cylindrical regions like arms during rotation due to non-rigid blending of transformations.^[24] Advanced methods like dual quaternion skinning address these by representing bone transformations as unit dual quaternions, which preserve rigidity during blending and mitigate the candy-wrapper artifact without significant computational overhead.^[5] Common artifacts in LBS, such as volume loss from collapsing or unnatural stretching at joints, can be corrected using techniques like corrective blend shapes, where precomputed offset meshes for specific poses are linearly interpolated to adjust the skinned result, or higher-order deformations that incorporate additional geometric constraints. These fixes enhance visual fidelity while maintaining the efficiency of the underlying skeletal binding.^[24]

Animation and Kinematics

In skeletal animation, keyframe animation serves as a foundational method for defining character motion by specifying complete bone poses at discrete time intervals, known as keyframes. These poses typically include rotations represented as Euler angles or quaternions, along with translations and scales for each bone. Interpolation between keyframes generates intermediate poses, often using spline-based curves such as cubic Bézier or Hermite splines to control timing, easing, and smoothness, ensuring fluid transitions without abrupt changes. Forward kinematics (FK) computes the global position and orientation of each bone by propagating transformations hierarchically from the root bone through to the leaf bones, typically via successive matrix multiplications in the kinematic chain. This approach is computationally efficient and intuitive for animators to set direct joint rotations, but it poses challenges for precise control of distal end-effectors, such as a character's hand or foot, often necessitating manual iterative adjustments to proximal joints to achieve desired placements.^[27] Inverse kinematics (IK) addresses the limitations of FK by solving for joint rotations that position an end-effector at a specified target location, enabling natural movements like accurate foot placement during locomotion to prevent sliding artifacts. Iterative numerical methods, such as the Jacobian transpose technique, approximate the solution by computing the Jacobian matrix of end-effector velocities with respect to joint angles and updating angles proportionally to the error gradient, converging quickly for real-time applications. The core objective is to minimize the Euclidean distance between the target and current end-effector positions:

d = \left\| \mathbf{p}_{\text{target}} - \mathbf{p}_{\text{end-effector}} \right\|

through successive chain adjustments, with damping often added to avoid singularities. Beyond basic keyframing and kinematics, advanced techniques enhance expressiveness and realism in skeletal animation. Motion blending combines multiple pre-recorded animation clips—such as transitioning from idle to walking—by linearly or nonlinearly interpolating bone transformations weighted by parameters like speed or direction, facilitating seamless variations from a compact library of motions. Layering, including additive animations, overlays secondary motions onto a base animation by adding relative offsets to bone rotations or positions, for instance, superimposing a gesture like waving onto a full-body walk cycle without disrupting the primary motion. Integration with motion capture data drives the skeleton by retargeting real-time or pre-recorded performer joint trajectories to the character's rig, preserving captured nuances like weight shifts while adapting to proportional differences in skeleton topology. Ragdoll physics extends kinematic animation into dynamic simulations by modeling the skeleton as a tree of rigid bodies connected by physical joints and constraints, responding to external forces and collisions via numerical integration of Newtonian equations. This technique is commonly applied post-keyframed animation for reactive sequences, such as character falls or impacts, where animator-defined poses blend with physics-driven deformations to yield believable secondary motions like limb flailing.

Advantages and Limitations

Key Benefits

Skeletal animation provides significant computational efficiency by animating complex models through a hierarchical bone structure, requiring fewer keyframes than per-vertex or keyframe-based methods, which reduces both storage needs and processing demands.^[28] In comparative studies, skeletal approaches achieve higher frame rates, such as improved FPS in real-time scenarios, while using less memory by storing only bone transformations rather than complete frame data for every vertex.^[28] This efficiency stems from the hierarchical propagation of transformations, allowing smooth interpolation across the skeleton without redundant calculations for individual mesh elements.^[29] A key advantage lies in its reusability and modularity, as animations can be retargeted to different characters with similar rigs, such as adapting humanoid motions to varied body proportions, thereby saving substantial time in production workflows.^[30] Retargeting techniques preserve high-level motion features like posture and timing through constraint-based mapping, enabling the reuse of motion capture data across assets without recapturing or manually rekeying sequences.^[30] This modularity facilitates rapid iteration and asset sharing in animation pipelines, reducing labor costs associated with creating bespoke animations for each model.^[30] Skeletal animation enables realistic articulation by simulating natural joint-based movements, where bone influences allow vertices to deform smoothly around articulation points, mimicking biological constraints.^[29] This approach supports secondary motions, such as the dynamic sway of cloth or hair, through bone-driven deformations that propagate physical-like effects without separate simulations. Compared to keyframe methods, which often result in unnatural interpolations, skeletal hierarchies provide greater physical plausibility, ensuring coherent and believable deformations during complex poses.^[29] For real-time performance, skeletal animation incurs low CPU and GPU overhead in modern engines, making it ideal for interactive applications by leveraging efficient matrix transformations and GPU-accelerated skinning.^[31] Techniques like velocity-based skinning further enhance this by enabling stylized effects at interactive speeds, even on large meshes, with minimal additional computation beyond standard bone updates.^[31] The technique's scalability allows it to handle both simple animations, like walk cycles driven by basic bone chains, and complex ones, such as facial expressions using specialized bone subsets, without proportional increases in resource demands.^[32] In large-scale simulations, skeletal methods support thousands of agents by optimizing blending and offsets, maintaining performance across varying complexity levels.^[32]

Primary Drawbacks

One primary drawback of skeletal animation lies in the deformation artifacts inherent to linear blend skinning (LBS), the most common skinning method, which can cause unnatural distortions such as joint collapsing or candy-wrapper effects during large rotations. For instance, when a joint rotates significantly (e.g., an elbow bending sharply), the linear interpolation of transformation matrices results in a rank-deficient matrix that collapses the mesh volume, leading to stretching or implosion at joints. These issues often necessitate artist interventions like corrective blend shapes to mitigate visible flaws, increasing production time.^[24]^[33] Rigging in skeletal animation introduces significant complexity, as creating detailed skeletons with numerous bones and precise weight paintings demands extensive manual effort and expertise, elevating setup time and error risk. Overly intricate rigs can lead to unnatural skin sliding if weights are poorly distributed, where vertices fail to deform smoothly across bone influences, resulting in visible seams or erratic motion. This complexity is particularly challenging for characters with varied anatomies, requiring custom adjustments to maintain structural integrity without compromising animation flexibility. Recent advances in AI-based auto-rigging and skinning methods, such as those using generative priors, are automating much of this process, thereby alleviating some of the manual complexity.^[34]^[35]^[36] Skeletal animation inherently struggles with realism for soft tissues, as it primarily models rigid bone transformations without simulating muscles, fat layers, or volume preservation, leading to flat or implausible deformations in areas like the abdomen or thighs. Standard LBS treats skin as a weighted envelope around bones, ignoring lateral tissue interactions or hysteresis in muscle response, which limits lifelike jiggle or bulging effects. Achieving more authentic soft body dynamics typically requires layering additional physics-based simulations, complicating the pipeline. Recent frameworks, such as spring decomposed skinning, enable real-time secondary motions to better approximate soft tissue dynamics within the skeletal pipeline.^[37]^[38]^[39] Performance bottlenecks arise from high bone counts in skeletal rigs, which strain real-time rendering by increasing computational demands for matrix calculations and vertex transformations, especially on lower-end hardware. Complex rigs with many bones can cause frame rate drops in applications like video games, as each skinned mesh must process bone hierarchies per frame, exacerbating CPU or GPU load during crowd scenes or intricate animations. Optimization techniques are often needed to cull unnecessary bones or batch computations, but these trade-offs can reduce animation fidelity.^[16]^[40] Platform inconsistencies further hinder skeletal animation workflows, as animations authored in one software or engine may not transfer seamlessly to another due to differences in bone hierarchies, scaling, or rest poses, often resulting in distorted proportions or broken kinematics without dedicated retargeting. Retargeting tools are essential to map skeletons across platforms, but mismatches in joint orientations or attachment points can still produce artifacts like foot sliding or limb stretching, demanding iterative adjustments.^[41]

Applications

In Video Games and Interactive Media

Skeletal animation plays a pivotal role in video games and interactive media by enabling real-time character deformation and movement, allowing for responsive interactions in dynamic environments. In character controllers, it facilitates procedural animations for player avatars, where bone transformations are blended with user inputs to generate natural locomotion. For instance, systems like Unity's Animation Rigging package use inverse kinematics to adjust skeletal poses in response to controller inputs, creating adaptive walking and running cycles that align with terrain or velocity changes. This approach ensures fluid, context-aware movements without pre-authoring every scenario, enhancing immersion in open-world games. Integration with physics engines further extends skeletal animation's utility for realistic dynamic interactions. Ragdoll simulations transition animated skeletons to physics-driven joints upon events like character death or impacts, simulating limp body responses. In games such as the Tomb Raider series, this technique produces convincing collision-based falls and environmental interactions, blending pre-recorded animations with real-time physics calculations for emergent behaviors. Such systems rely on joint constraints mapped to skeletal bones, allowing seamless switching between controlled animation and passive simulation to maintain performance in fast-paced action sequences. To support interactivity on resource-constrained platforms, skeletal animations incorporate optimizations like level-of-detail (LOD) systems for bones and compression techniques. LOD variants reduce bone counts and animation precision for distant characters, preserving visual fidelity near the player while minimizing computational overhead; Unreal Engine's Skeletal Mesh LODs, for example, automatically cull non-essential bones based on screen distance. Compression methods, such as keyframe quantization and curve fitting, shrink asset sizes for mobile games by representing bone rotations with fewer bits, achieving up to 80% reduction in storage without perceptible quality loss. These strategies enable smooth playback across devices, crucial for multiplayer titles with numerous animated entities.^[42]^[43] Real-time retargeting exemplifies skeletal animation's adaptability in multiplayer and immersive contexts. In online games, animations are dynamically mapped between differing skeletons to accommodate player-customized avatars, ensuring consistent motion across varied body types without manual re-authoring. This process uses pose-matching algorithms to align bone hierarchies, supporting synchronized interactions in titles like those built on Unreal Engine. In VR and AR applications, motion-tracked avatars leverage skeletal rigs to mirror user movements via full-body tracking, adjusting joint positions in real-time for immersive embodiment; systems like those in Meta's Horizon Worlds employ this for natural gesturing and locomotion in social virtual spaces.^[44]^[45] Looking ahead, AI-driven procedural skeletal animations promise emergent behaviors in games, where machine learning generates bone adjustments on-the-fly for unpredictable scenarios. Techniques like generative adversarial networks synthesize novel poses from input data, enabling characters to react uniquely to environmental stimuli or player actions, as explored in recent surveys of AI for character animation. This evolution could reduce reliance on hand-crafted assets, fostering more lifelike, adaptive interactions in future interactive media. As of 2025, GPU-based solutions enable efficient large-scale skeletal animation simulations for crowd scenes in games.^[46]

In Film, Animation, and Visual Effects

Skeletal animation plays a pivotal role in character animation within film and visual effects, enabling animators to create expressive performances through keyframed rigs that control hierarchical bone structures for natural movement and deformation. In The Lord of the Rings: The Two Towers (2002), Weta Digital utilized a detailed skeletal rig for Gollum, consisting of bones overlaid with a volume-preserving muscle system that allowed muscles to flex realistically and push against the skin, facilitating Andy Serkis's performance capture data to drive subtle facial expressions and body contortions for the character's dual personality. This approach marked a breakthrough in blending actor-driven motion with digital rigging, allowing for emotionally nuanced animations that integrated seamlessly with live-action footage.^[47] Motion capture pipelines in film leverage skeletal data captured from actors and map it onto digital rigs to achieve lifelike creature movements, often combining early analog techniques with emerging digital tools. For the dinosaurs in Jurassic Park (1993), Industrial Light & Magic (ILM) employed skeletal animation in Softimage software, where motion data from Phil Tippett's go-motion armatures—equipped with encoders—was retargeted to CG models, enabling fluid locomotion like the T. rex's sprint that blended practical and digital elements for photorealistic results. This pipeline established skeletal mapping as a foundation for creature animation, influencing subsequent VFX workflows by allowing animators to refine captured data for anatomical accuracy.^[17] In visual effects integration, skeletal animation combines with simulations to enhance creature realism, particularly by layering muscle dynamics onto core skeletons for complex interactions. In Avatar (2009), Weta Digital's Tissue system built upon skeletal rigs by simulating anatomical layers—muscles, fascia, and fat—that responded dynamically to bone movements, driving skin deformations for Na'vi characters and creatures like the thanator during high-impact scenes such as battles and flights. This integration allowed animators to focus on primary skeletal controls while automated simulations added secondary motions, like muscle bulging under stress, resulting in believable organic behaviors within Pandora's environment.^[48] Adaptations of skeletal animation extend to 2D productions, where tools like Spine facilitate sprite-based rigging for efficient, fluid character movements in animated series. In shows emulating vintage styles, such as The Cuphead Show! (2022), 2D skeletal techniques using bone hierarchies on cutout sprites enable animators to achieve rubber-hose elasticity and squash-and-stretch effects reminiscent of 1930s cartoons, streamlining the creation of expressive gestures without full frame-by-frame redrawing. Spine's workflow supports this by allowing bones to deform meshes attached to images, making it suitable for narrative-driven TV animation that prioritizes stylistic consistency across episodes.^[49]^[50] The production workflow for skeletal animation in film and VFX emphasizes close collaboration between riggers and animators, spanning from storyboarding to final rendering to ensure rigs support creative storytelling. Riggers initially construct hierarchical skeletons based on concept art and anatomical references during pre-production, incorporating controls for facial expressions and locomotion that animators test iteratively in software like Maya. Throughout animation and effects stages, teams refine bindings and simulations—such as muscle layers—to resolve deformations, with feedback loops allowing animators to adjust poses while riggers optimize for rendering efficiency, culminating in composited shots that integrate skeletal-driven elements with live-action or environments. This collaborative process, as seen in projects like Marvel's Thor: Ragnarok (2017), underscores riggers' critical role in providing intuitive tools that empower animators to deliver performance fidelity.^[51]

References

[1]
Skeletal animation - Valve Developer Community
Jun 23, 2024 · Skeletal animation is a processor-efficient and relatively simple animation system that can simulate any jointed object, from people to insects to machinery.Missing: computer graphics definition authoritative
[2]
[PDF] Skinning Mesh Animations - Stanford Computer Graphics Laboratory
In this paper, we show that skinning techniques can also be used to automatically skin deformable mesh animations, without any need for specifying skeletons or ...
[3]
[PDF] Real-time Skeletal Animation - Virtual Server List
This thesis aims to study skeletal animation from both practical and theoretical viewpoints.
[4]
Chapter 2: Skeletons - UCSD CSE
A character's skeleton is a pose-able framework of bones connected by articulated joints, arranged in a tree data structure.Missing: fundamentals | Show results with:fundamentals
[5]
[PDF] Animation and shadows 1 Summary 2 Skeletal animation 3 ...
Skeletal animation is a technique for animating meshes, such as those that represent creatures in a. 3D game. The basic idea is that the model is defined by ...Missing: fundamentals | Show results with:fundamentals
[6]
[PDF] A Survey of Real-Time Crowd Rendering - UPCommons
An alternative approach is per-vertex animation, also re- ferred to as ... skeletal animation. In the field of crowd rendering, Ulicny et al. [UCT04] ...
[7]
2D skeletons — Godot Engine (stable) documentation in English
Introduction: When working with 3D, skeletal deforms are common for characters and creatures and most 3D modeling applications support it.
[8]
A Brief History of Stop-Motion - Focus Features
Jun 19, 2012 · Since the birth of motion pictures, stop-motion animation, like that ... The ball-and-socket metal armatures created for the latter set a template ...
[9]
Skeletal Animation: A Comprehensive Guide - GarageFarm
Skeletal animation is a foundational technique in 3D computer graphics, widely used in video games, films, and other digital media.Missing: authoritative | Show results with:authoritative
[10]
How Autodesk Maya Became the Industry Standard
The breakthrough for Autodesk came with the introduction of Maya. Maya v1.0 was released in 1998 and quickly made a name for itself in the 3D animation world.
[11]
How 'Jurassic Park' Made History 25 Years Ago, Propelling ...
Jun 8, 2018 · It was the first time that computer-generated characters interacted with human actors on screen. How has the technology improved since then?
[12]
[PDF] Character Animation and Skinning - UT Computer Science
Data Needed for Rigging. • Mesh data exists in world space in A-pose/T-pose. • Skeleton defines hierarchy of bone angles and lengths in A-pose. • Animation ...
[13]
What is Rigging in Animation - Unity
Character rigging, or skeletal animation, is the first step in animating a digital character. Binding a model to a skeletal hierarchy of bones and controls ...Missing: computer | Show results with:computer<|control11|><|separator|>
[14]
[PDF] Automatic Rigging for Part-Based Shape Modeling and Deformation
In the state-of-the-art character animation pipeline, a rig takes the form of a skeleton, a cycle-free graph whose nodes are called joints and whose edges ...
[15]
What Is Rigging in Animation? Skeletal Animation Explained - Adobe
In animation, rigging works by construction a series of bones (or skeleton) for your 2D or 3D model. This could be an animal or human character, but you can ...
[16]
[PDF] Robust and Accurate Skeletal Rigging from Mesh Sequences
Rigging a model currently consists of two main steps: building a hierarchical skeleton with rigid bones connected by joints, and skinning the 3D model to define ...
[17]
What skeleton does metahuman use? - Unreal Engine Forums
Jan 4, 2023 · To update my previous post, the skeleton of a Metahuman does have 5 spine bones, plus all the corrective joints, but not the facial rig, which ...
[18]
[PDF] Direct Skinning Methods and Deformation Primitives
Linear blend skinning, also known as skeleton-subspace deformation, (single-weight-)enveloping, or matrix-palette skinning, is the basic and most well known ...Missing: seminal | Show results with:seminal
[19]
[PDF] Skinning with Dual Quaternions - GameDevs.org
May 2, 2007 · Historically, the idea of skin deformation by an underlying skeleton is credited to [Magnenat-Thalmann et al. 1988]. Since then, sev- eral ...
[20]
[PDF] Fast Automatic Skinning Transformations - Interactive Geometry Lab
Linear blend skinning deformations are governed by vertex weights wi and vertices with similar weights undergo similar rotations (re- gardless of spatial ...Missing: seminal | Show results with:seminal
[21]
[PDF] Skinning with Dual Quaternions
In this paper, we present a novel GPU-friendly skin- ning algorithm based on dual quaternions. We show that this ap- proach solves the artifacts of linear blend ...Missing: seminal | Show results with:seminal
[22]
[PDF] Mathematics for Mathematics for Inverse Kinematics
• The goal of inverse kinematics is to compute the vector of joint DOFs ... Jacobian Transpose. • Another technique is just to use the transpose of the ...
[23]
A Comparative Study of Skeletal and Keyframe Animations in a ...
Our experiment results suggest that the skeletal model has major advantages over the key frame model, both in terms of the FPS (frame per second) and the memory ...Missing: computational efficiency
[24]
A Skinning Method in Real-time Skeletal Character Animation
Aug 9, 2025 · provides more physical plausibility than key-frame animation. Instead of manipulating every single vertex directly, “bone” as.
[25]
Reuse of Motion Capture Data in Animation: A Review - ResearchGate
Aug 7, 2025 · The aim of animation retargeting procedures is to preserve the motion of the performer such that the highlevel features of an action are ...
[26]
Velocity Skinning for Real-time Stylized Skeletal Animation
Interactive on CPU, our method allows for GPU implementation, yielding real-time performances even on large meshes. Animator control is supported through a ...
[27]
(PDF) Techniques for Skeletal-Based Animation in Massive Crowd ...
Feb 4, 2022 · This paper focuses on improving the performance, variety, and usability of crowd animation systems. Performing the blending operation on the ...
[28]
Skinning with dual quaternions - ACM Digital Library
We show that this approach solves the artifacts of linear blend skinning at minimal additional cost. Upgrading an existing animation system (e.g., in a ...
[29]
[PDF] DESIGN AND OPTIMIZATION OF RIGGING TECHNIQUES FOR ...
This research paper's goal is to investigate the development and optimisation of rigging methods for animated, articulated characters. This study attempts to ...
[30]
[PDF] Robust and Accurate Skeletal Rigging from Mesh Sequences
Rigging a model currently consists of two main steps: building a hierarchical skeleton with rigid bones connected by joints, and skinning the 3D model to define ...
[31]
[PDF] Modeling and Simulation of Skeletal Muscle for Computer Graphics
As well as the muscle-based skeletal dynamics, a physics- based soft tissue simulator was incorporated to represent realistic flesh deformation during body ...
[32]
[PDF] Simulation and Control of Skeleton-driven Soft Body Characters
Abstract. In this paper we present a physics-based framework for simulation and control of human-like skeleton-driven soft body characters. We.
[33]
Performance Tips & Tricks - Animation | Epic Developer Community
Apr 14, 2025 · Performance issues with animation tend to break down into two different areas: the game thread cost of ticking Skeletal Meshes and the ...
[34]
Animation Retargeting in Unreal Engine - Epic Games Developers
Through retargeting, you can prevent your animated skeletons from losing their proportions or becoming unnecessarily deformed when using animations from ...Missing: platform inconsistencies
[35]
Compressing Skeletal Animation Data | Riot Games Technology
Jul 24, 2015 · With this post, I'll introduce the two main techniques we pursued: quantization and curve fitting. Compression always leads to a trade-off ...Missing: mobile | Show results with:mobile
[36]
Skeletal Mesh LODs in Unreal Engine - Epic Games Developers
In Unreal Engine, you can generate Skeletal Mesh LOD (Level of Detail) model variants to optimize gameplay. ... An array of Bones to be removed from the skeleton ...
[37]
Real-time motion retargeting to highly varied user-created ...
This paper introduces a novel system for animating characters whose morphologies are unknown at the time the animation is created.
[38]
automatic skeleton adjustment for self-avatars in virtual reality
Jul 6, 2023 · Our work provides an affordable and quick method to automatically extract user measurements and adjust the virtual humanoid skeleton to the exact dimensions.
[39]
How Lord of the Rings' Gollum Changed CGI Forever - Vulture
Dec 11, 2018 · Weta Digital Effect Supervisor Eric Saindon looks back on the process of creating a new breed of CG character with Andy Serkis's ...
[40]
Breathing Life into the Dinosaurs of Jurassic Park - ILM
Jul 9, 2015 · With Jurassic Park, director Steven Spielberg masterfully combined Stan Winston's practical puppetry with ILM's fully computer-generated dinosaurs.
[41]
Tissue | Wētā FX
Richard Dorling, developed the linear-elastic finite-element system 'Tissue' to build muscles, skin, and fat for creatures in such films as Avatar, Rise of ...Missing: dynamics | Show results with:dynamics
[42]
https://dev.epicgames.com/documentation/en-us/unreal-engine/skeletal-mesh-lods-in-unreal-engine
[43]
'The Cuphead Show!' on Netflix animation style, explained
Feb 18, 2022 · The team behind 'The Cuphead Show!' explains how they crafted its 1930s-inspired animation in the digital age.
[44]
Building character with Thor (part2) - fxguide
Nov 20, 2017 · Riggers roles are often passed over in discussion of character animation but their role is critical, as any animator will testify. ILM. Hulk.