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Main Authors: Liu, Yaoli, Ding, Yao-Xiang, Zhou, Kun
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.23515
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author Liu, Yaoli
Ding, Yao-Xiang
Zhou, Kun
author_facet Liu, Yaoli
Ding, Yao-Xiang
Zhou, Kun
contents This paper proposes FreeFuse, a training-free framework for multi-subject text-to-image generation through automatic fusion of multiple subject LoRAs. In contrast to prior studies that focus on retraining LoRA to alleviate feature conflicts, our analysis reveals that simply spatially confining the subject LoRA's output to its target region and preventing other LoRAs from directly intruding into this area is sufficient for effective mitigation. Accordingly, we implement Adaptive Token-Level Routing during the inference phase. We introduce FreeFuseAttn, a mechanism that exploits the flow matching model's intrinsic semantic alignment to dynamically match subject-specific tokens to their corresponding spatial regions at early denoising timesteps, thereby bypassing the need for external segmentors. FreeFuse distinguishes itself through high practicality: it necessitates no additional training, model modifications, or user-defined masks spatial conditions. Users need only provide subject activation words to achieve seamless integration into standard workflows. Extensive experiments validate that FreeFuse outperforms existing approaches in both identity preservation and compositional fidelity. Our code is available at https://github.com/yaoliliu/FreeFuse.
format Preprint
id arxiv_https___arxiv_org_abs_2510_23515
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle FreeFuse: Multi-Subject LoRA Fusion via Adaptive Token-Level Routing at Test Time
Liu, Yaoli
Ding, Yao-Xiang
Zhou, Kun
Computer Vision and Pattern Recognition
This paper proposes FreeFuse, a training-free framework for multi-subject text-to-image generation through automatic fusion of multiple subject LoRAs. In contrast to prior studies that focus on retraining LoRA to alleviate feature conflicts, our analysis reveals that simply spatially confining the subject LoRA's output to its target region and preventing other LoRAs from directly intruding into this area is sufficient for effective mitigation. Accordingly, we implement Adaptive Token-Level Routing during the inference phase. We introduce FreeFuseAttn, a mechanism that exploits the flow matching model's intrinsic semantic alignment to dynamically match subject-specific tokens to their corresponding spatial regions at early denoising timesteps, thereby bypassing the need for external segmentors. FreeFuse distinguishes itself through high practicality: it necessitates no additional training, model modifications, or user-defined masks spatial conditions. Users need only provide subject activation words to achieve seamless integration into standard workflows. Extensive experiments validate that FreeFuse outperforms existing approaches in both identity preservation and compositional fidelity. Our code is available at https://github.com/yaoliliu/FreeFuse.
title FreeFuse: Multi-Subject LoRA Fusion via Adaptive Token-Level Routing at Test Time
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2510.23515