REVIEW 3 major objections 6 minor 53 references
Behave Your Motion: Habit-preserved Cross-category Animal Motion Transfer
T0 review · 3 major / 6 minor · reviewed 2026-08-06 · deepseek-v4-flash
Pith's one-line read Animal motion transfer can preserve species-specific habits rather than only re-targeting skeletons, and text descriptions extend the transfer to species whose motion has never been seen.
desk verdict A plausible habit-preserving motion transfer pipeline with a useful new dataset, but the zero-shot unseen-species claim rests on untested text-embedding retrieval. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The central mechanism is the habit latent $z_c$, a per-category random variable modeled with a normalizing-flow prior $p(z)=p_w(w)\,|\det \partial F_\alpha/\partial w|^{-1}$, learned by a separate transformer-based encoder $q_\varphi(z|m_c)$ for each category. The motion decoder is conditioned on $z_c$ along with the LLM text embedding $g_c$, and for unseen categories the habit-retrieval step selects the observed category with minimum Euclidean distance in the text-embedding space and reuses its habit latent as a proxy. The VQ-VAE codebook, trained with exponential moving average and codebook reset, provides the discrete motion representation that lets the source action and target habit be combined at inference.
What would settle it
Hold out entire species during training, run text-only habit retrieval for each held-out species, and compare the transferred motion to ground-truth target motion with FID and 1-NNA; if the scores are not clearly better than retrieving a random observed habit, the zero-shot generalization claim fails.
Extended reading notes
Core claim
The paper's central claim is that cross-category animal motion transfer should be formulated as transferring the source action while preserving the target species' habitual behavior, an objective distinct from skeletal retargeting and style transfer. This is achieved by conditioning a vector-quantized motion autoencoder on a category-specific habit latent together with an LLM-derived text embedding: during inference, the source motion is encoded into discrete codes, the target category supplies the habit latent either from a per-category normalizing-flow prior or, for unseen species, via nearest-neighbor retrieval in the text-embedding space, and the decoder produces motion that retains the source action but adopts the target's natural articulation. The authors validate the approach on a new DeformingThings4D-skl dataset and on AnimalML3D, with quantitative metrics favoring the method over direct and style-transfer baselines.
Load-bearing premise
The load-bearing premise is that nearest-neighbor retrieval in the text-embedding space returns an observed species whose habit latent is biologically and behaviorally appropriate for an unseen species, and the paper provides no quantitative held-out test of this premise.
Editorial extensions
If this is right
- The same source motion will produce different, species-appropriate joint articulation when transferred to different target quadrupeds while keeping the action recognizable.
- Motion transfer to a species with no motion data becomes possible from a text description alone, via nearest-neighbor habit retrieval.
- The new DeformingThings4D-skl dataset supplies skeleton-bound quadruped motion with habit descriptions, supporting future motion generation and transfer tasks.
- Quantitative gains over direct transfer and style transfer on FID, Intra-FID, downstream-task FID, and MPJPE support habit conditioning as an axis separate from style.
Reading between the lines
- The zero-shot claim rests on the geometry of the text-embedding space holding that a nearest observed species is behaviorally similar to the unseen species; this reader would want a held-out-species quantitative test, since the paper only shows qualitative examples.
- If nearest-neighbor habit retrieval works, the same mechanism could be extended to blend habit latents from multiple neighboring species rather than picking one, potentially producing intermediate gaits.
- The paper's framing suggests human motion habits (for example, body-type or gender differences) as a natural next domain, but the authors note that current human style datasets encode exaggerated actions rather than subtle habitual cues.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper proposes a VQ-VAE-based framework for cross-category quadruped motion transfer that aims to preserve the target species' habitual motion characteristics. It introduces a category-specific habit encoder modeled with normalizing flows, an LLM-based text encoder that supplies semantic category knowledge, and a habit-retrieval mechanism for transferring motion to previously unobserved species. The authors also introduce DeformingThings4D-skl, a skeletal animal motion dataset with habit descriptions. Reported experiments compare the method with direct transfer and a style-transfer baseline, showing improvements in FID, Intra-FID, downstream transfer FID, diversity, 1-NNA, and MPJPE on both DeformingThings4D-skl and AnimalML3D.
Significance. If validated, the paper would make a useful contribution by defining and attacking a new task: habit-preserved cross-category animal motion transfer. The dataset extension with skeletal bindings and habitual descriptions is a concrete asset for the community. The architectural idea of separating a category-specific habit latent from a generic motion VQ-VAE and bridging to unseen categories through an LLM text embedding is plausible and is backed by substantial quantitative gains on the observed categories. However, the central zero-shot claim currently rests on qualitative examples only, and the evaluation design has gaps (limited baselines, no variance reporting) that prevent the results from fully supporting the claimed superiority.
major comments (3)
- [§3.3.2, Eq. (11)] The paper's headline claim of transfer to 'previously unobserved species' rests on BGE nearest-neighbor habit retrieval, but no quantitative held-out evaluation is provided. Tables 1-3 evaluate only the 17 training categories, and Figure 4 is qualitative. This is load-bearing because the retrieval step is the only mechanism that supplies a habit latent for an unseen category, and the assumption that Euclidean proximity in a web-text embedding space implies kinematic similarity is untested. I request a held-out category experiment (e.g., remove several categories during training, compute downstream FID/Intra-FID/MPJPE for transfers into those categories using the Eq. (11) proxy, and compare with an oracle habit latent trained on the held-out category) or a corresponding revision of the claims.
- [§4.1.2, Tables 1-3] The reported downstream-task FID is computed against the same target-category data that was used to train the category-specific habit encoder and to derive the target text embedding that conditions generation. This makes the metric, at least in part, a measure of reproduction of the conditioning distribution rather than an independent test of habit preservation. Please clarify whether the metric is computed on held-out motion sequences of the same categories or on the training set, and report the metric separately for source-target category pairs that were not jointly seen during training.
- [§4.1.4, Tables 1-2] The quantitative comparison is limited to two baselines (direct transfer and Aberman et al. style transfer) with no error bars, confidence intervals, or significance tests, and no animal-motion-aware baseline is included. Since the paper claims 'substantial improvements' and 'superiority,' the authors should report variance across seeds or bootstrap resamples and add at least one recent quadruped motion-generation/retargeting baseline to demonstrate that the gains are not an artifact of metric choice.
minor comments (6)
- [§1, last paragraph] The word 'anction-level' should read 'action-level.'
- [§4.2, Tables 1-2] The misspelling 'Abermen' appears in the table text; it should be 'Aberman.'
- [§3.2.1 and Eq. (4)] The symbol \hat f is first defined as a sampled codebook index, but the losses \mathcal{L}_{emb} and \mathcal{L}_{com} use \hat f as if it were a codebook vector; please disambiguate the notation, for example by writing e_{\hat f} for the selected code, and make Eq. (1)'s decoder input notation consistent.
- [§4.1.1] The description of DeformingThings4D-skl does not specify how the train/validation split is made; please state whether categories overlap between the splits.
- [§4.4.2, Table 4] The text reports alpha=0.5 as the best trade-off, but alpha=0.75 achieves a lower FID (0.037 vs. 0.053) with only a slightly higher downstream FID (0.017 vs. 0.012); please clarify the selection criterion used to identify the best hyperparameter.
- [§4.1.1] The paper does not state whether DeformingThings4D-skl and the implementation will be released; please include a data/code availability statement.
Circularity Check
No significant circularity: the core transfer pipeline is not equivalent to its inputs by construction; the zero-shot generalization claim is under-validated but that is a correctness concern, not circularity.
full rationale
The paper's derivation chain does not reduce to its own inputs. The habit latent z_c is learned from target-category motion data, and the downstream FID/Intra-FID metrics compare generated motions to held-out target-category distributions; this is a standard generative-model evaluation, not a fitted parameter renamed as a prediction. The cross-category transfer composes a source motion's content latent with a target category's habit latent during inference, and the training objective reconstructs source motions with their own category, so the transfer evaluation is not statistically forced by the training loss. The only potentially circular-looking element is Eq. 11, where an unseen category's habit latent is set equal to the nearest observed category's latent in BGE text-embedding space. That is an unvalidated assumption about the semantic structure of text embeddings, and the paper provides only qualitative evidence for zero-shot generalization. However, an unsupported assumption is not circularity: Eq. 11 does not redefine the output as the input, nor does it smuggle the conclusion into the premise. There are no load-bearing self-citations; the VQ-VAE backbone and quantization strategies are credited to external prior work without author overlap. The introduction of 'habitual behaviors' is a modeling and evaluation choice rather than a renaming that makes the result true by definition. Overall, the central transfer mechanism has independent empirical content, and the zero-shot claim, while insufficiently evaluated, is not circular.
Assumptions & free parameters
free parameters (4)
- velocity loss coefficient alpha =
0.5
- commitment loss coefficient beta =
0.02
- codebook size =
512x512
- quantization temperature tau =
not reported
assumptions (4)
- domain assumption VQ-VAE discrete codes can represent quadruped motion sequences well enough for reconstruction and transfer.
- domain assumption A normalizing-flow prior per category can model the distribution of habit latents.
- domain assumption GPT-4o behavioral descriptions and BGE embeddings place animals with similar habits close in text space.
- domain assumption The horse-skeleton reference with 21 joints supports faithful rigging of all 21 categories in DeformingThings4D-skl.
Cite this review
Pith. "Pith review of Behave Your Motion: Habit-preserved Cross-category Animal Motion Transfer." pith.science (2026). https://pith.science/paper/Z5HA3O7D
@misc{pith2026250707394,
author = {Pith},
title = {Pith review of: Behave Your Motion: Habit-preserved Cross-category Animal Motion Transfer},
year = {2026},
howpublished = {\url{https://pith.science/paper/Z5HA3O7D}},
note = {Machine review of arXiv:2507.07394}
}
read the original abstract
Animal motion embodies species-specific behavioral habits, making the transfer of motion across categories a critical yet complex task for applications in animation and virtual reality. Existing motion transfer methods, primarily focused on human motion, emphasize skeletal alignment (motion retargeting) or stylistic consistency (motion style transfer), often neglecting the preservation of distinct habitual behaviors in animals. To bridge this gap, we propose a novel habit-preserved motion transfer framework for cross-category animal motion. Built upon a generative framework, our model introduces a habit-preservation module with category-specific habit encoder, allowing it to learn motion priors that capture distinctive habitual characteristics. Furthermore, we integrate a large language model (LLM) to facilitate the motion transfer to previously unobserved species. To evaluate the effectiveness of our approach, we introduce the DeformingThings4D-skl dataset, a quadruped dataset with skeletal bindings, and conduct extensive experiments and quantitative analyses, which validate the superiority of our proposed model.
Figures
Reference graph
Works this paper leans on
-
[1]
Kfir Aberman, Peizhuo Li, Dani Lischinski, Olga Sorkine-Hornung, Daniel Cohen- Or, and Baoquan Chen. 2020. Skeleton-aware networks for deep motion retarget- ing. ACM Transactions on Graphics (TOG) 39, 4 (2020), 62–1
work page 2020
-
[2]
Kfir Aberman, Yijia Weng, Dani Lischinski, Daniel Cohen-Or, and Baoquan Chen
-
[3]
Tenglong Ao, Zeyi Zhang, and Libin Liu. 2023. Gesturediffuclip: Gesture diffusion model with clip latents. ACM Transactions on Graphics (TOG) 42, 4 (2023), 1–18
work page 2023
-
[4]
Ilya Baran and Jovan Popović. 2007. Automatic rigging and animation of 3d characters. ACM Transactions on graphics (TOG) 26, 3 (2007), 72–es
work page 2007
-
[5]
Benjamin Biggs, Thomas Roddick, Andrew Fitzgibbon, and Roberto Cipolla. 2019. Creatures great and smal: Recovering the shape and motion of animals from video. In Computer Vision–ACCV 2018: 14th Asian Conference on Computer Vision, Perth, Australia, December 2–6, 2018, Revised Selected Papers, Part V 14 . Springer, 3–19
work page 2019
-
[6]
Xi Chen, Diederik P Kingma, Tim Salimans, Yan Duan, Prafulla Dhariwal, John Schulman, Ilya Sutskever, and Pieter Abbeel. 2016. Variational lossy autoencoder. arXiv preprint arXiv:1611.02731 (2016)
arXiv 2016
-
[7]
Enric Corona, Albert Pumarola, Guillem Alenya, and Francesc Moreno-Noguer
-
[8]
Rishabh Dabral, Muhammad Hamza Mughal, Vladislav Golyanik, and Christian Theobalt. 2023. Mofusion: A framework for denoising-diffusion-based motion synthesis. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition. 9760–9770
work page 2023
Show all 53 references
-
[9]
In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition
Context-aware human motion prediction. In Proceedings of the IEEE/CVF conference on computer vision and pattern recognition . 6992–7001
-
[10]
Michael Gleicher. 1998. Retargetting motion to new characters. In Proceedings of the 25th annual conference on Computer graphics and interactive techniques . 33–42
1998
-
[11]
Laurent Dinh, Jascha Sohl-Dickstein, and Samy Bengio. 2016. Density estimation using real nvp. arXiv preprint arXiv:1605.08803 (2016)
2016 arXiv
-
[12]
Jonathan Ho, Ajay Jain, and Pieter Abbeel. 2020. Denoising diffusion probabilistic models. Advances in neural information processing systems 33 (2020), 6840–6851
2020
-
[13]
Martin Heusel, Hubert Ramsauer, Thomas Unterthiner, Bernhard Nessler, and Sepp Hochreiter. 2017. Gans trained by a two time-scale update rule converge to a local nash equilibrium. Advances in neural information processing systems 30 (2017)
2017
-
[14]
Siyuan Huang, Zan Wang, Puhao Li, Baoxiong Jia, Tengyu Liu, Yixin Zhu, Wei Liang, and Song-Chun Zhu. 2023. Diffusion-based generation, optimization, and planning in 3d scenes. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition . 16750–16761
2023
-
[15]
Daniel Holden, Jun Saito, and Taku Komura. 2016. A deep learning framework for character motion synthesis and editing. ACM Transactions on Graphics (TOG) 35, 4 (2016), 1–11
2016
-
[16]
Boeun Kim, Jungho Kim, Hyung Jin Chang, and Jin Young Choi. 2024. MoST: Motion Style Transformer between Diverse Action Contents. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition . 1705–1714
2024
-
[17]
Deok-Kyeong Jang, Soomin Park, and Sung-Hee Lee. 2022. Motion puzzle: Arbi- trary motion style transfer by body part. ACM Transactions on Graphics (TOG) 41, 3 (2022), 1–16
2022
-
[18]
Nhat Le, Thang Pham, Tuong Do, Erman Tjiputra, Quang D Tran, and Anh Nguyen. 2023. Music-driven group choreography. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition . 8673–8682
2023
-
[19]
Diederik P Kingma. 2013. Auto-encoding variational bayes. arXiv preprint arXiv:1312.6114 (2013)
2013 arXiv
-
[20]
Jehee Lee and Sung Yong Shin. 1999. A hierarchical approach to interactive motion editing for human-like figures. In Proceedings of the 26th annual conference on Computer graphics and interactive techniques . 39–48
1999
-
[21]
Hsin-Ying Lee, Xiaodong Yang, Ming-Yu Liu, Ting-Chun Wang, Yu-Ding Lu, Ming-Hsuan Yang, and Jan Kautz. 2019. Dancing to music. Advances in neural information processing systems 32 (2019)
2019
-
[22]
Shujie Li, Lei Wang, Wei Jia, Yang Zhao, and Liping Zheng. 2022. An iterative solution for improving the generalization ability of unsupervised skeleton motion retargeting. Computers & Graphics 104 (2022), 129–139
2022
-
[23]
Buyu Li, Yongchi Zhao, Shi Zhelun, and Lu Sheng. 2022. Danceformer: Music con- ditioned 3d dance generation with parametric motion transformer. InProceedings of the AAAI Conference on Artificial Intelligence , Vol. 36. 1272–1279
2022
-
[24]
David Lopez-Paz and Maxime Oquab. 2016. Revisiting classifier two-sample tests. arXiv preprint arXiv:1610.06545 (2016)
2016 arXiv
-
[25]
Yang Li, Hikari Takehara, Takafumi Taketomi, Bo Zheng, and Matthias Nießner
-
[26]
OpenAI. 2024. GPT-4o. https://openai.com/index/hello-gpt-4o/ Accessed on October 25, 2024
2024
-
[27]
Alec Radford. 2018. Improving language understanding by generative pre- training. (2018)
2018
-
[28]
Takeru Miyato and Masanori Koyama. 2018. cGANs with projection discriminator. arXiv preprint arXiv:1802.05637 (2018)
2018 arXiv
-
[29]
Li Siyao, Weijiang Yu, Tianpei Gu, Chunze Lin, Quan Wang, Chen Qian, Chen Change Loy, and Ziwei Liu. 2022. Bailando: 3d dance generation by actor- critic gpt with choreographic memory. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition . 11050–11059
2022
-
[30]
Wenfeng Song, Xingliang Jin, Shuai Li, Chenglizhao Chen, Aimin Hao, Xia Hou, Ning Li, and Hong Qin. 2024. Arbitrary Motion Style Transfer with Multi- condition Motion Latent Diffusion Model. In Proceedings of the IEEE/CVF Confer- ence on Computer Vision and Pattern Recognition...
2024
-
[31]
Ali Razavi, Aaron Van den Oord, and Oriol Vinyals. 2019. Generating diverse high-fidelity images with vq-vae-2. Advances in neural information processing systems 32 (2019)
2019
-
[32]
Guy Tevet, Brian Gordon, Amir Hertz, Amit H Bermano, and Daniel Cohen-Or
-
[34]
Seyoon Tak and Hyeong-Seok Ko. 2005. A physically-based motion retargeting filter. ACM Transactions on Graphics (ToG) 24, 1 (2005), 98–117
2005
-
[35]
A Vaswani. 2017. Attention is all you need. Advances in Neural Information Processing Systems (2017)
2017
-
[36]
Zan Wang, Yixin Chen, Tengyu Liu, Yixin Zhu, Wei Liang, and Siyuan Huang
-
[37]
Yu-Hui Wen, Zhipeng Yang, Hongbo Fu, Lin Gao, Yanan Sun, and Yong-Jin Liu. 2021. Autoregressive stylized motion synthesis with generative flow. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition. 13612–13621
2021
-
[38]
Aaron Van Den Oord, Oriol Vinyals, et al. 2017. Neural discrete representation learning. Advances in neural information processing systems 30 (2017)
2017
-
[39]
Shitao Xiao, Zheng Liu, Peitian Zhang, and Xingrun Xing. 2023. LM-Cocktail: Re- silient Tuning of Language Models via Model Merging. arXiv:2311.13534 [cs.CL]
2023 arXiv
-
[40]
Zhangsihao Yang, Mingyuan Zhou, Mengyi Shan, Bingbing Wen, Ziwei Xuan, Mitch Hill, Junjie Bai, Guo-Jun Qi, and Yalin Wang. 2024. OmniMotionGPT: Animal Motion Generation with Limited Data. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVP...
2024
-
[41]
Advances in Neural Information Processing Systems 35 (2022), 14959–14971
Humanise: Language-conditioned human motion generation in 3d scenes. Advances in Neural Information Processing Systems 35 (2022), 14959–14971
2022
-
[42]
Hao Zhang, Di Chang, Fang Li, Mohammad Soleymani, and Narendra Ahuja
-
[43]
Shitao Xiao, Zheng Liu, Peitian Zhang, and Niklas Muennighoff. 2023. C-Pack: Packaged Resources To Advance General Chinese Embedding. arXiv:2309.07597 [cs.CL]
2023 arXiv
-
[44]
Jianrong Zhang, Yangsong Zhang, Xiaodong Cun, Yong Zhang, Hongwei Zhao, Hongtao Lu, Xi Shen, and Ying Shan. 2023. Generating human motion from textual descriptions with discrete representations. In Proceedings of the IEEE/CVF conference on computer vision and pattern recogniti...
2023
-
[45]
Peitian Zhang, Shitao Xiao, Zheng Liu, Zhicheng Dou, and Jian-Yun Nie. 2023. Retrieve Anything To Augment Large Language Models. arXiv:2310.07554 [cs.IR]
2023
-
[46]
Hongwei Yi, Hualin Liang, Yifei Liu, Qiong Cao, Yandong Wen, Timo Bolkart, Dacheng Tao, and Michael J Black. 2023. Generating holistic 3d human motion from speech. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition. 469–480
2023
-
[47]
Zixiang Zhou and Baoyuan Wang. 2023. Ude: A unified driving engine for human motion generation. In Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition. 5632–5641
2023
-
[48]
Wentao Zhu, Xiaoxuan Ma, Dongwoo Ro, Hai Ci, Jinlu Zhang, Jiaxin Shi, Feng Gao, Qi Tian, and Yizhou Wang. 2023. Human motion generation: A survey.IEEE Transactions on Pattern Analysis and Machine Intelligence (2023)
2023
-
[49]
Jiaxu Zhang, Junwu Weng, Di Kang, Fang Zhao, Shaoli Huang, Xuefei Zhe, Linchao Bao, Ying Shan, Jue Wang, and Zhigang Tu. 2023. Skinned motion retargeting with residual perception of motion semantics & geometry. In Pro- ceedings of the IEEE/CVF Conference on Computer Vision and...
2023
-
[52]
Zeyu Zhang, Yiran Wang, Biao Wu, Shuo Chen, Zhiyuan Zhang, Shiya Huang, Wenbo Zhang, Meng Fang, Ling Chen, and Yang Zhao. 2024. Motion Avatar: Generate Human and Animal Avatars with Arbitrary Motion. arXiv preprint arXiv:2405.11286 (2024)
2024 arXiv
-
[2020]
ACM Transactions on Graphics (TOG) 39, 4 (2020), 64–1
Unpaired motion style transfer from video to animation. ACM Transactions on Graphics (TOG) 39, 4 (2020), 64–1
2020
-
[2021]
In Proceedings of the IEEE/CVF International Conference on Computer Vision
4DComplete: Non-rigid motion estimation beyond the observable surface. In Proceedings of the IEEE/CVF International Conference on Computer Vision. 12706– 12716
-
[2022]
In European Conference on Computer Vision
Motionclip: Exposing human motion generation to clip space. In European Conference on Computer Vision . Springer, 358–374
-
[2024]
arXiv:2405.14017 [cs.CV]
MagicPose4D: Crafting Articulated Models with Appearance and Motion Control. arXiv:2405.14017 [cs.CV]
Reviewed August 6, 2026 · model on record in the stance chip above.
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