| Work | Venue/Year | One-line takeaway | Relevance to our X2 effort |
|---|
| DeepMimic (Peng et al.) | SIGGRAPH 2018 | RL imitation of mocap clips with reference-state init & early termination — the founding recipe. | RSI/ET machinery we use daily descends from this. |
| AMP (Peng et al.) | SIGGRAPH 2021 | Adversarial motion priors replace hand-designed imitation rewards. | Alternative reward paradigm if explicit tracking rewards keep fighting us. |
| PHC / PULSE (Luo et al.) | ICCV 2023 / ICLR 2024 | Perpetual simulated humanoid tracking of ~all AMASS; distilled latent skill space. | The sim-side ceiling proof: near-universal tracking is possible with enough data+compute. |
| MaskedMimic (Tessler et al.) | SIGGRAPH Asia 2024 | Masked motion inpainting unifies tracking, VR, text control in one physics policy. | Blueprint for multi-mode conditioning (SONIC's 3-encoder design echoes this). |
| Work | Venue/Year | One-line takeaway | Relevance to our X2 effort |
|---|
| H2O / OmniH2O (He et al.) | IROS/CoRL 2024 | Real-time human-to-humanoid teleop via RL tracking + retargeted refs. | First proof the sim recipe survives real G1-class hardware. |
| HumanPlus (Fu et al.) | CoRL 2024 | Whole-body shadowing + autonomous skills from human data. | Data-flywheel story for humanoid skills. |
| ExBody / ExBody2 (Cheng et al.) | RSS 2024 / 2025 | Expressive whole-body control; decoupled upper/lower tracking targets. | Upper/lower decoupling mirrors our SOMA-lower + GMR-upper graft. |
| HOVER (NVIDIA) | ICRA 2025 | Distills multiple control modes into one neural whole-body controller. | Multi-mode distillation = likely future step after tracking works. |
| ASAP (He et al.) | RSS 2025 | Aligns sim and real physics via residual action models for agile skills. | The sim2real delta-learning we may need for X2 deployment. |
| TWIST (Ze et al.) | 2025 | Teleoperated whole-body imitation system on real humanoids. | Same GMR author lineage; teleop-grade retargeting constraints. |
| BeyondMimic / KungfuBot | 2025 | Dynamic/agile motion tracking pushed to highly dynamic skills on real robots. | Upper bound on what tracking-based control achieves on hardware. |
| Work | Venue/Year | One-line takeaway | Relevance to our X2 effort |
|---|
| GEAR-SONIC (NVIDIA) | arXiv:2511.07820, 2025 | Universal motion tracking at scale (8k+ hrs, multi-GPU): ~99% success on G1; 3 conditioning encoders. | A historical released-default common-v4 replay scored 104/126 = 82.54%; the audited primary 50k result is 480/512 = 93.75%, and the old 38% figure was a mislabeled custom XY/3D diagnostic. |
| HoloMotion-1 (Horizon Robotics) | arXiv:2605.15336, 2026 | MoE-Transformer motion foundation model; zero-shot tracking; video-reconstructed + mocap + in-house data; HoloRetarget 3000+ FPS; HoloSMPL unified capture. | Candidate independent comparison framework — evaluation in progress. |
| GR00T N1/N1.5 (NVIDIA) | 2025 | VLA stack whose action layer is a decoupled whole-body controller. | Where tracking controllers plug into task-level autonomy. |
| Work | Venue/Year | One-line takeaway | Relevance to our X2 effort |
|---|
| GMR (Ze et al.) | 2025 | Real-time general motion retargeting, per-frame differential IK, any URDF. | Our production retargeter; no contact awareness by design (teleop origins) — root cause of our feet defects. |
| SOMA Retargeter (NVIDIA) | 2026 | Offline trajectory LM-IK + feet stabilization + limit clamping on Newton/Warp; G1-only public configs. | Dissected in our postmortem: lower body excellent on X2, upper body numerically unstable (elbow singularity, a “1-DOF waist” attribution later found incorrect — X2 has a 3-DOF waist). |
| OmniRetarget | 2025 | Interaction-preserving retargeting for loco-manipulation data. | Relevant when we add object interaction clips. |
| SEED dataset (Bones Studio) | HF 2026 | Large SOMA-skeleton mocap library + official G1 retargets (SOMA-produced). | Our source corpus (122k clips); SOMA-BVH archive downloaded (45.5 GB). |
| AMASS / SMPL-X | ICCV 2019 | Unified mocap archive / expressive parametric body model. | Upstream of every retargeting pipeline here. |