Papers › HybrIK-X: Hybrid Analytical-Neural Inverse Kinematics for Whole-body Mesh Recovery

HybrIK-X: Hybrid Analytical-Neural Inverse Kinematics for Whole-body Mesh Recovery

12 Apr 2023arXiv:2304.05690archive 2025-07-28

Jiefeng Li, Siyuan Bian, Chao Xu, Zhicun Chen, Lixin Yang, Cewu Lu

Recovering whole-body mesh by inferring the abstract pose and shape parameters from visual content can obtain 3D bodies with realistic structures. However, the inferring process is highly non-linear and suffers from image-mesh misalignment, resulting in inaccurate reconstruction. In contrast, 3D keypoint estimation methods utilize the volumetric representation to achieve pixel-level accuracy but may predict unrealistic body structures. To address these issues, this paper presents a novel hybrid inverse kinematics solution, HybrIK, that integrates the merits of 3D keypoint estimation and body mesh recovery in a unified framework. HybrIK directly transforms accurate 3D joints to body-part rotations via twist-and-swing decomposition. The swing rotations are analytically solved with 3D joints, while the twist rotations are derived from visual cues through neural networks. To capture comprehensive whole-body details, we further develop a holistic framework, HybrIK-X, which enhances HybrIK with articulated hands and an expressive face. HybrIK-X is fast and accurate by solving the whole-body pose with a one-stage model. Experiments demonstrate that HybrIK and HybrIK-X preserve both the accuracy of 3D joints and the realistic structure of the parametric human model, leading to pixel-aligned whole-body mesh recovery. The proposed method significantly surpasses the state-of-the-art methods on various benchmarks for body-only, hand-only, and whole-body scenarios. Code and results can be found at https://jeffli.site/HybrIK-X/

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Jeff-sjtu/HybrIK mentioned on GitHubpytorchMIT report
jeffffffli/HybrIK mentioned on GitHubpytorch report

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flip Jeff-sjtu/HybrIK/hybrik/models/HRNetSMPLXCamKid.py community (archive-listed) unverified MIT (permissive) · fabada0c3f6b8840 · report
focalLength_mm2px Jeff-sjtu/HybrIK/hybrik/datasets/agora_smplx.py community (archive-listed) unverified MIT (permissive) · ed832a8183efcc97 · report
get_focal Jeff-sjtu/HybrIK/hybrik/datasets/agora_smplx.py community (archive-listed) unverified MIT (permissive) · 733d8811b481fdbe · report
norm_heatmap Jeff-sjtu/HybrIK/hybrik/models/HRNetSMPLXCamKid.py community (archive-listed) unverified MIT (permissive) · 0635936243f338d5 · report
norm_heatmap Jeff-sjtu/HybrIK/hybrik/models/simple3dposeBaseSMPL.py community (archive-listed) unverified MIT (permissive) · a828d7ddc0f76aac · report
project Jeff-sjtu/HybrIK/hybrik/datasets/agora_smplx.py community (archive-listed) unverified MIT (permissive) · 8cc86609ecbd6234 · report
weighted_l1_loss Jeff-sjtu/HybrIK/hybrik/models/criterion.py community (archive-listed) unverified MIT (permissive) · 3b94245b39283e5c · report
weighted_laplace_loss Jeff-sjtu/HybrIK/hybrik/models/criterion.py community (archive-listed) unverified MIT (permissive) · 86dec2a5c79f02f6 · report

Tasks

3D Human Pose Estimation3D Human ReconstructionKeypoint Estimation

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
3D Human Pose Estimation 3DPW HybrIK (HRNet-W48) MPJPE 71.6 #24 of 119 Archive leaderboard report
3D Human Pose Estimation 3DPW HybrIK (HRNet-W48) MPVPE 82.3 #24 of 119 Archive leaderboard report
3D Human Pose Estimation 3DPW HybrIK (HRNet-W48) PA-MPJPE 41.8 #24 of 119 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK-X B-MPJPE 67.2 #3 of 11 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK-X B-MVE 68.5 #3 of 11 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK-X B-NMJE 72.3 #3 of 11 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK-X B-NMVE 73.7 #3 of 11 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK B-MPJPE 77 #4 of 11 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK B-MVE 73.9 #4 of 11 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK B-NMJE 84.6 #4 of 11 Archive leaderboard report
3D Human Pose Estimation AGORA HybrIK B-NMVE 81.2 #4 of 11 Archive leaderboard report
3D Human Pose Estimation MPI-INF-3DHP HybrIK (HRNet-W48) AUC 47.3 #46 of 108 Archive leaderboard report
3D Human Pose Estimation MPI-INF-3DHP HybrIK (HRNet-W48) MPJPE 91 #46 of 108 Archive leaderboard report
3D Human Pose Estimation MPI-INF-3DHP HybrIK (HRNet-W48) PCK 87.1 #46 of 108 Archive leaderboard report
3D Human Reconstruction AGORA HybrIK-X FB-MPJPE 107.6 #1 of 5 Archive leaderboard report
3D Human Reconstruction AGORA HybrIK-X FB-MVE 112.1 #1 of 5 Archive leaderboard report
3D Human Reconstruction AGORA HybrIK-X FB-NMJE 115.7 #1 of 5 Archive leaderboard report
3D Human Reconstruction AGORA HybrIK-X FB-NMVE 120.5 #1 of 5 Archive leaderboard report

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