Flexible Motion Generation from Language and Style References

TL;DR

FlexMoGen framework generates high-quality human motions from language and style references.

cs.CV 🔴 Advanced 2026-09-08 4 views
Kai Weixian Lan Bodie Criswell Briana Fedkiw Zhan Zhang Joseph Teran Daniel Holden
motion synthesis style transfer diffusion models animation machine learning

Key Findings

Methodology

FlexMoGen framework generates motions using a variational style encoder and a text-to-motion latent diffusion model. It integrates relative positional encoding and a lightweight style adaptation module, supporting long, multi-style synthesis.

Key Results

  • In experiments, FlexMoGen achieved the best balance between content fidelity and style reflection, performing excellently across multiple datasets.
  • Compared to existing methods, FlexMoGen excels in long-sequence generation and style diversity.
  • Ablation studies show that the style adaptation module significantly improves style transfer accuracy.

Significance

This research offers greater flexibility in animation generation, accurately reflecting target styles while preserving semantic content. It addresses the limitations of traditional methods in capturing style details.

Technical Contribution

FlexMoGen introduces a variational style encoder without style supervision, combined with a lightweight style adaptation module, significantly enhancing motion generation flexibility and diversity.

Novelty

FlexMoGen is the first to achieve long-sequence, multi-style motion generation without style labels, overcoming previous limitations in style control.

Limitations

  • The model may underperform with extremely complex style combinations.
  • Requires substantial computational resources for training.

Future Work

Future work will explore more efficient training methods and broader style combinations to further enhance model applicability.

AI Executive Summary

In modern computer graphics, character animation is a fundamental component. However, traditional manual animation and motion capture methods are both costly and time-consuming. The FlexMoGen framework offers a flexible approach to human motion synthesis by combining natural language descriptions and style references. It employs a variational style encoder and a text-to-motion latent diffusion model, supporting long, multi-style synthesis.

The core technologies of FlexMoGen include relative positional encoding and a lightweight style adaptation module, enabling it to accurately reflect target styles while maintaining high semantic content. Experimental results show that the framework achieves the best balance between content fidelity and style reflection.

Despite significant advancements in motion generation, FlexMoGen still faces limitations in handling extremely complex style combinations. Future research will focus on improving training efficiency and expanding the diversity of style combinations.

Deep Analysis

Background

Character animation is a crucial field in modern computer graphics. Traditional methods like manual animation and motion capture are costly and time-consuming. Recently, data-driven motion synthesis methods have emerged, especially text-based generative models like VAEs and diffusion models.

Core Problem

Existing methods have limitations in capturing fine-grained motion style details, particularly in long-sequence and multi-style generation. Text descriptions alone struggle to fully express nuanced style characteristics.

Innovation

FlexMoGen achieves long-sequence, multi-style motion generation without style labels using a variational style encoder and a lightweight style adaptation module, overcoming previous limitations.

Methodology

  • �� Variational Style Encoder: Learns rich style representations without style labels.
  • �� Style Adaptation Module: Modulates motion style through learnable bias vectors.
  • �� Relative Positional Encoding: Provides fine-grained temporal control.

Experiments

Experiments used an internal high-quality MoCap dataset and the 100STYLE dataset, evaluating the model's performance in long-sequence and multi-style generation. Ablation studies validated the effectiveness of each component.

Results

FlexMoGen performed excellently across multiple datasets, especially in long-sequence generation and style diversity. Ablation studies showed that the style adaptation module significantly improved style transfer accuracy.

Applications

This technology can be used in game animation, film production, and other fields, providing more efficient and flexible animation generation solutions.

Limitations & Outlook

The model may underperform with extremely complex style combinations and requires substantial computational resources for training.

Plain Language Accessible to non-experts

Imagine a dance choreographer who needs to create dances based on different music styles. FlexMoGen is like this choreographer, generating dance moves that match the desired style based on text descriptions and style references. By combining language and style, FlexMoGen can maintain the dance theme while accurately reflecting the music's stylistic features.

ELI14 Explained like you're 14

Imagine you're playing a game where you can tell a character what action to do, like dance or run. FlexMoGen is like a super-smart game engine that not only understands your commands but also lets the character perform actions in different styles you like. Isn't that cool?

Glossary

Variational Style Encoder

An encoder that learns rich motion style representations without requiring style labels.

Used in FlexMoGen to capture nuanced motion style characteristics.

Diffusion Model

A generative model that generates data by gradually denoising it.

Used in the text-to-motion generation process.

Style Adaptation Module

A module that modulates motion style through learnable bias vectors.

Used in FlexMoGen for precise style control.

Relative Positional Encoding

An encoding method that provides fine-grained temporal control.

Enhances temporal sequence generation in FlexMoGen.

Ablation Study

An experimental method that evaluates the importance of model components by removing or altering them.

Used to validate the effectiveness of FlexMoGen components.

Open Questions Unanswered questions from this research

  • 1 How to maintain high performance with more complex style combinations?
  • 2 Can the same generation quality be achieved with fewer computational resources?

Applications

Immediate Applications

Game Animation

FlexMoGen can provide game developers with flexible animation generation tools to quickly create character motions in different styles.

Long-term Vision

Film Production

In film and television production, FlexMoGen can help creators generate more diverse and complex character motions, enhancing visual effects.

Abstract

We introduce FlexMoGen, a novel framework for flexible human motion synthesis conditioned on both natural language descriptions and motion style references. Text prompts are effective at defining semantic content, but they are often limited in capturing fine-grained style details such as timing, limb articulation, and expressive dynamics. A style example clip supplements the text by conveying these nuanced motion characteristics directly, enabling the model to preserve high-level intent while reproducing the desired stylistic traits. Given a text prompt and a style example clip, FlexMoGen generates high-quality motions that preserve semantic content while faithfully reflecting the target style, offering users greater control over the animation generation process. Unlike prior methods that rely on discrete style labels and do not generalize to long or multi-style generation, FlexMoGen learns a variational style encoder without style supervision and supports long, time-varying, multi-style synthesis. Our framework jointly pre-trains the style encoder and a text-to-motion latent diffusion model within a unified architecture, modulating motion style through a lightweight adaptation module. It integrates an efficient relative positional encoding scheme and is trained on both stylized and non-stylized datasets, enabling strong generalization to unseen text-style combinations. Experiments show that FlexMoGen achieves the best balance between content fidelity and style reflection.

cs.CV cs.GR cs.LG