NeurIPS 2026 Papers

Recent 3D indoor scene generation methods often produce layouts with limited spatial feasibility, where pathways are blocked and objects are difficult to access or use, restricting their applicability in virtual reality and embodied environments. To address this challenge, this paper presents a new paradigm for 3D indoor scene generation that explicitly models interaction feasibility through a carefully designed geometric abstraction, termed the Interaction-Oriented Human Proxy (IOHP). The IOHP serves as a compact yet spatially expressive representation for human interaction occupancy, and can be directly inferred by large language models without task-specific training. Building on IOHP, we formulate layout optimization as a unified objective that resolves geometric conflicts between the proxy and scene elements, while using the proxy as a bridge to preserve functional relationships among furniture, thereby improving overall usability and accessibility. Benefiting from this design, our method eliminates reliance on data-driven human preference learning and complex layout-planning pipelines, producing accessible, usable, and spatially coherent scenes in an efficient and stable manner. Extensive experiments demonstrate that our approach significantly improves layout quality and spatial plausibility, highlighting the role of human-centric interaction modeling in 3D scene generation.

Longitudinal radiology report generation increasingly conditions on prior images and reports. This history is clinically valuable, but it creates a source-validity failure mode: a generator can carry prior-only findings into the current report. Weintroduce source-causal robustness, a stress-test and control framework that holds the current chest X-ray fixed while intervening on historical context. On a full eligible MIMIC-CXR longitudinal study (18,716 pairs; 93,580 generations across five source conditions), historical context consistently trades fewer missed findings for more unsupported positives. Matched wrong-history, the key negative control, increases proxy-defined false positives by +0.366 per report while reducing false negatives by −0.129; random wrong-history yields an even larger false positive stress signal (+0.465 FP/report). We propose the Source-Causal Finding Router (SCFR), a source-validity controller trained with within-evaluation subject exclusion. Across three held-out evaluations, SCFR repairs matched wrong-history false-positive inflation by −0.343, −0.550, and −0.457 per report, passes Holm corrected primary testing at the bootstrap resolution floor (Holm-adjusted p ≤ 0.0012), and satisfies fixed current-only parity margins. Cross-generator stress panels with RadInfer and Libra, together with ReXPref-Prior, RadGraph2, Chest ImaGenome, ablations, and case review, support the mechanism. These results establish a protocol-defined state-of-the-art source-causal robustness/control result for longitudinal radiology report generation under matched wrong-history stress tests.

CT report generation (CTRG) requires models to summarize three-dimensional anatomical context and pathological findings from hundreds of axial slices. Existing methods typically learn a direct image-to-text mapping, providing limited mechanisms for modeling how CT evidence evolves across slices or how reports respond to controlled changes in latent lesion-related factors. We propose SliceWorld, a CT-specific world-state framework that treats an axial CT scan as an ordered sequence along the z-axis. SliceWorld encodes prefix CT evidence into factor-aware latent states containing anatomy, lesion, and uncertainty components, and projects these states into world tokens used for multi-step future-slice feature prediction, lesion-factor intervention, and LLM-based report generation. The model is first pretrained on CT slice sequences with predictive, factor-aware, and counterfactual objectives, and is then fine-tuned on paired CT-report data. Experiments on M3D-Cap and CT-RATE show that SliceWorld improves natural language generation metrics and clinically oriented automatic evaluation. Further analyses demonstrate multi-horizon future-slice prediction, measurable factor alignment, reduced-slice robustness, and selective lesion-sensitive report modulation.

Plot-to-code generation has been greatly advanced by recent multimodal large language models (MLLMs). However, existing studies mainly focus on one-pass generation or iterative sampling guided by verifier-based filtering, which does not align with the typical human programming workflow of generate first, then iteratively error-location and fix. This naturally motivates a test-time refinement paradigm for plot-to-code generation.In this work, we present the first study on plot-to-code generation via iterative test-time refinement. We propose a Visual-Code Diagnostics framework that enables refinement through visual feedback from source code. Specifically, we first categorize generation errors into four coarse-grained types, and then train lightweight discriminators to recognize and localize these errors based on the rendered visual outputs and corresponding code. Unlike traditional compiler- or debugger-based verification, our approach performs iterative refinement guided by one diagnostics system, enabling more effective semantic and visual correction during test time. Extensive experiments demonstrate that our method consistently improves generation quality across diverse generators and significantly outperforms strong test-time scaling baselines.

Code evolution is a family of techniques that rely on large language models to search through possible computer programs by evolving existing code. While code evolution pipelines have shown impressive performance across domains, many are highly complex and are typically not compared to simpler alternatives. To prevent bad comparisons from stagnating the field, we propose two simple baselines and compare them to popular pipelines across three domains: finding better mathematical bounds, designing agentic scaffolds, and machine learning competitions. Surprisingly, the baselines match or outperform existing methods across all domains, prompting a closer look at which factors drive performance in different settings. For mathematical bounds, we find that the search space matters far more than the exact search algorithm, with both simple and complex methods performing similarly given the same search space. Thus, expanding the search space is what matters for improving performance, and does so across all pipelines. Moreover, different domain knowledge embedded in prompts can significantly affect the search's efficiency, potentially leading to overestimating a pipeline's sample efficiency. For automated agentic scaffold design, we show that typical high-variance evaluations lead to all automated search methods picking subpar scaffolds relative to a simple majority vote. To mitigate this, we propose improved evaluation procedures that reduce stochasticity while keeping the search economically feasible. Overall, these results indicate that further improving code evolution's performance depends more on the setup surrounding the search pipeline than on the pipeline itself. We hope these insights will enable developing new code evolution methods and help spur meaningful progress in the field.

LLM/VLM-based digital agents have advanced rapidly thanks to scalable sandboxes for coding, web navigation, and computer use, which provide rich interactive training grounds. In contrast, embodied agents still lack abundant, diverse, and automatically generated 3D environments for interactive learning. Existing embodied simulators rely on manually crafted scenes or procedural templates, while recent LLM-based 3D generation systems mainly produce static scenes rather than deployable environments with verifiable tasks and standard learning interfaces. We introduce SimWorld Studio, an open-source platform built on Unreal Engine 5 for generating evolving embodied learning environments. At its core is SimCoder, a tool/skill-augmented coding agent that writes and executes engine-level code to construct physically grounded 3D worlds from language/image instructions. SimCoder self-evolves by using verifier feedback (e.g., compilation errors, physics checks, VLM critiques) to revise environments and autonomously add reusable tools and skills to its library. Generated worlds are exported as Gym-style environments for embodied agent learning. SimWorld Studio further enables co-evolution between environment generation and embodied learning: agent performance feedback guides SimCoder to generate adaptive curricula near the learner’s capability frontier, so that environments become increasingly challenging as the embodied agent improves. Three case studies on embodied navigation show that self-evolution improves generation reliability, generated environments substantially improve embodied agent performance that generalizes to unseen benchmarks, and co-evolution yields an 18-point success-rate gain over fixed-environment learning and a 40-point gain over an untrained agent.

Diffusion large language models (dLLMs) have recently emerged as a promising alternative to autoregressive (AR) LLMs, offering faster inference through parallel or blockwise decoding. However, their masked language modeling formulation remains incompatible with standard token-level speculative decoding, one of the most effective acceleration techniques for AR models. In AR decoding, the causal mask preserves temporally valid token-level contexts, enabling a target model to verify multiple drafted tokens in a single forward pass. In contrast, dLLMs rely on mask tokens and bidirectional attention, causing the effective context to change across denoising steps and preventing direct token-level speculative verification. To bridge this gap, we propose a simple but effective speculative decoding algorithm for diffusion language models, named SimSD, which mainly adopts a plug-and-play masking strategy that equips dLLMs with temporally valid token-level contexts for speculative decoding. Our method explicitly introduces reference tokens from draft-model predictions and designs an attention mask that regulates their interaction with current-step tokens, allowing dLLMs to compute valid logits for drafted tokens in a single forward pass. This restores the key verification ability provided by causal masking in AR models while preserving the parallel decoding advantages of dLLMs. The proposed method is training-free and can be flexibly integrated with other acceleration techniques such as KV cache and blockwise decoding. Experiments on SDAR-family dLLMs across four benchmarks show that our method achieves up to \(7.46\times\) higher decoding throughput while maintaining and even improving average generation quality. Our code will be publicly released.

Cross-camera RAW-to-sRGB mapping seeks to convert smartphone RAW captures into DSLR-quality sRGB images, yet the large domain gap between linear RAW and nonlinear sRGB spaces makes this task highly challenging. Existing methods mainly condition on pixel-level supervision and local RAW cues, where content preservation and domain translation remain entangled in low-level measurements. We propose SemISP, a semantic-guided diffusion framework that uses scene semantics as a domain-invariant anchor for cross-domain generation. Specifically, we adopt a frozen DINOv3 as the sRGB semantic backbone and develop a Domain Alignment Adapter to extract sRGB-consistent semantic representations from RAW inputs through parameter-efficient adaptation. Because semantic priors and RAW signals operate at fundamentally different information levels, and the diffusion denoising process follows a coarse-to-fine trajectory, we further design a Time-aware Dual-stream Adaptive Modulation (TDAM) module that separately encodes both condition streams and uses the diffusion timestep to dynamically balance their contributions---emphasizing semantic anchoring at early stages and fine-grained RAW details at later ones. Experiments on two established cross-camera benchmarks show consistent improvements over prior methods in both fidelity and perceptual quality.

We introduce SemGeo-Gen, an unsupervised method for generating approximate cross-instance semantic-geometric supervision from weakly aligned 3D object collections. Our goal is not to recover exact point-level correspondences, which are often ambiguous across different instances and would require expensive, impractical manual supervision at scale. Instead, we automatically produce approximate correspondences that are semantically meaningful, geometrically consistent, and diverse enough to train modern correspondence models. Given only coarse category-level rotation alignment, SemGeo-Gen lifts multi-view DINOv2 features to 3D, aligns object instances using continuous piecewise-affine registration, and prunes candidate matches using semantic consistency. The resulting 3D correspondences can be projected into rendered views, yielding scalable 3D-3D, 3D-2D, and 2D-2D supervision without manual annotation. We validate the generated correspondences against sparse human annotations from KeypointNet, obtaining 93% PCK@0.10 and 97% PCK@0.15. More importantly, we show that using the generated correspondences for synthetic pretraining improves recent state-of-the-art semantic correspondence models on SPair-71k after fine-tuning on real data, with gains of up to 5 PCK@0.10 points. Together, these results indicate that approximate semantic-geometric supervision generated from 3D assets can improve real-image correspondence learning and serve as a scalable alternative to costly manual annotation. Code and generated data will be released upon acceptance.

Today, verifier-guided best-of-$N$ inference is a common way to spend test-time compute in language modeling, code generation, and alignment: generate $N$ candidates, score them with a verifier or reward model, and deploy the highest-scoring output. This paper argues that the relevant reliability object is not average verifier accuracy but \emph{selected-tail reliability}, namely the behavior of the output chosen after optimizing over $N$ noisy public scores; we derive exact selected-rank exposure laws for best-of-$N$ selection and finite-verifier resource laws showing that selected public optimism scales at the $\sqrt{\log N/m}$ regime under $m$ units of verifier evidence. We then separate public optimism from hidden utility harm, showing that public-score inflation alone is not a harm claim and that harm or uncertifiability requires public-hidden mismatch, tail dominance, count imbalance, or an unresolved selected-tail regime. Building on these results, we introduce Tail-Certified Compute Caps, a conservative procedure that certifies candidate budgets or refuses certification using selected-tail intervals, verifier-resource penalties, mismatch envelopes, and feasibility gates. In exact-verifier/public-hidden experiments, the theory predicts selected false-positive exposure and supports resource-aware cap decisions over an all-attempted denominator, while non-code candidate tables with pre-existing public human annotations serve as secondary scoped $K\ge16$ consistency checks under proxy/model-prior/verifier-style scores across Arena55K and Stanford SHP. Overall, the paper provides a reliability framework for verifier-guided inference-time scaling: candidate budgets should be justified by evidence about the selected tail that is actually deployed, not only by average verifier validation.

Flow matching has recently emerged as a strong paradigm for state-of-the-art text-to-image (T2I) generation, enabling high-quality generation with a small number of sampling steps. As these models are increasingly integrated into real-world applications, ensuring safe and non-sensitive content generation has become a critical requirement. However, adapting safety and concept removal methods to this new generation framework remains an open challenge. Specifically, prior methods largely rely on iterative trajectory steering across a number of denoising steps or on CLIP-centeric prompt embedding manipulation. These design assumptions pose fundamental bottlenecks for safety in flow matching-based T2I generation, where limited sampling steps constrain iterative correction and modern context-aware text encoders diminish the effectiveness of embedding-level interventions. In this paper, we propose VESFlow, a training-free safety method tailored to flow matching with extremely few sampling steps. Leveraging the fact that flow matching models learn the marginal velocity (or average velocity in MeanFlow), we directly edit the velocity field via a Bayesian decomposition of the safe-conditional posterior. VESFlow steers the trajectory toward safe outputs while leaving the conditioning prompt unchanged. Building on the observation that VESFlow leaves outputs unchanged under benign prompts, we further introduce a risk score filtering that bypasses velocity editing to reduce computational cost while preserving benign prompt generation. Based on this filtering, we proposed VESFlow+ which provides stronger safety protection when filtered by the risk score. Experimental results show that our method removes the target concept, reducing the detection rate by NudeNet to 6.3\% for step-4 model, while preserving fidelity on benign prompts. Code is available at the supplementary file.

Logical reasoning remains a major challenge for large language models (LLMs), particularly on structured problems that require precise constraint tracking, consistency preservation, and multi-step deduction. This challenge is especially acute for small-scale LLMs, which are more prone to producing inconsistent, redundant, or brittle reasoning trajectories. Existing approaches for improving logical reasoning largely optimize for final-answer correctness, providing only weak supervision over the intermediate reasoning process. In this work, we propose SPRING, a solver-guided reinforcement learning framework for logical reasoning that uses an SMT solver as a training-time verifier of intermediate reasoning steps to provide process-level supervision. SPRING introduces the notion of a novel reasoning step, namely, a step that is logically valid, consistent with the evolving reasoning state, and not already implied by previously accepted non-contradictory deductions. Based on this solver-based assessment, we design process rewards that encourage novel inferential progress while penalizing contradictory and uninformative reasoning steps. Evaluation results on two logical reasoning benchmarks, ZebraLogic and AR-LSAT, show that SPRING consistently outperforms baseline LLMs and outcome-only reward baselines. On ZebraLogic, SPRING improves puzzle accuracy by up to 49.71 and 15.43 points over the base LLM and outcome-only reward baseline, respectively. On AR-LSAT, SPRING improves the overall average score by up to 64.93 and 12.14 points over the base LLM and best-performing outcome-only reward baseline, respectively.

High-resolution 3D generation increasingly relies on voxel latents and multi-stage pipelines that first predict active structure and then synthesize local geometry. While effective, this design fragments continuous surfaces into many local tokens, inflates generation cost, and often weakens topological consistency for thin or highly connected shapes. We introduce **SILSA**, a topology-aware 3D generation framework that represents shapes with compact sliding-window slice latents. Instead of generating expensive voxel tokens, SILSA uses a fixed set of overlapping slices along the three canonical axes, where each token summarizes a local depth window to preserve cross-sectional continuity and support single-stage rectified-flow generation. A **Slice VAE** encodes oriented surface samples into multi-axis slice latents and reconstructs them with a sparse volumetric decoder, while a **Volumetric Anchor Lattice** coordinates directional slice streams through a shared 3D workspace. To preserve structural correctness, we introduce slice-level topology supervision that matches persistence diagrams and aligns Betti transitions across neighboring slices. Experiments show that SILSA improves structural fidelity while substantially reducing generation cost. SILSA improves PSNR by 8.7%, coverage by 5.96 absolute points, and Betti error by 9.2% over the strongest baseline, while using 70.0% fewer tokens than the next-most compact baseline and over 98% fewer tokens than sparse or hierarchical tokenizers, reducing training memory by 40.4% and inference time by 58.5%. Qualitative results further show improved preservation of thin structures, repeated components, and long-range connectivity.

Vector quantization (VQ) with autoregressive (AR) token modeling is a widely adopted and highly competitive paradigm for time-series generation. However, such models are fundamentally limited by exposure bias: during inference, errors can accumulate across sequential predictions, leading to pronounced quality degradation in long-horizon generation. To address this, we propose **SDFlow** (**S**imilarity-**D**riven **Flow** Matching), a non-autoregressive framework that operates entirely in the frozen VQ latent space and enables parallel sequence generation via flow matching. We tackle three key challenges in making this transition: (1) eliminating exposure bias by replacing step-wise token prediction with a global transport map; (2) mitigating the high-dimensionality of VQ token spaces via a low-rank manifold decomposition with a learned anchor prior over the latent manifold; and (3) incorporating discrete supervision into continuous transport dynamics by introducing a categorical posterior over codebook indices within a variational flow-matching formulation. Extensive experiments show that SDFlow achieves state-of-the-art performance, improving Discriminative Score and substantially reducing Context-FID, particularly for challenging long-sequence generation. Moreover, SDFlow provides significant inference speedups over autoregressive baselines, offering both high fidelity and computational efficiency. Code is available at *https://anonymous.4open.science/r/SDFlow-D6F3/*

Retrieval-Augmented Generation (RAG) mitigates Large Language Model (LLM) hallucinations by grounding generation in external knowledge. Although structure-augmented RAG methods improve multi-hop reasoning, they incur high indexing costs and degrade on simple queries. We argue that this robustness gap is driven by capacity bottlenecks in fixed-dimensional inner-product scoring. As corpora grow, semantically close passages create local regions where a base scorer cannot maintain sufficient separability. Reorganizing documents into trees or graphs can expose or partially mitigate this issue, but it does not by itself provide a stronger local scoring function. We propose Semantic Ambiguity Guided Capacity Expansion (SAGE), a lightweight RAG framework that detects such regions using document-side Local Separability Deficit and expands capacity only where needed. SAGE builds a two-layer semantic index, derives atomic query views from corpus passages, and calibrates a parameter-efficient hypernetwork to generate the local Ambiguity-Conditioned Scorers for selected nodes. Extensive experiments show that SAGE improves retrieval and QA performance over dense retrievers and structure-augmented baselines, achieving a better balance between single-hop, multi-hop retrieval accuracy, and robust scalability. Anonymous Code: https://anonymous.4open.science/r/SAGE-1676.

Scaling Vision-Language-Action (VLA) policy training requires diverse robot demonstration data, yet collecting such data remains expensive and labor-intensive. The community has explored ways to accelerate robot data collection: visual augmentation methods synthesize novel samples by editing visual elements in existing demonstrations, while systems such as UMI leverage wrist-mounted cameras to flexibly collect in-the-wild manipulation videos. However, the mismatched observation setups of these two directions leave them largely disconnected, limiting their synergistic potential for scalable robot data generation. To bridge this gap, we propose **RoboExo**, a generative framework for controllable wrist-to-exocentric conversion of robotic demonstrations. We introduce a geometry-motion factorization strategy that reconstructs canonical object-robot geometry and propagates motion states from noisy wrist-view videos, yielding reliable structural priors for cross-view synthesis. These priors guide a conditional video diffusion model to generate target-view exocentric videos that are spatially aligned, temporally coherent, and faithful to the underlying manipulation semantics. We evaluate RoboExo on a wrist-to-exo generation benchmark under both seen and unseen settings, where it consistently outperforms all baselines, reducing LPIPS by **76%** and FVD by **64\%**. Beyond generation quality, RoboExo improves VLA policy learning across six tasks, increasing the average success rate by **+30\%** with generated exocentric views. These results demonstrate RoboExo as an effective and scalable data engine for enriching low-cost UMI demonstrations. The code will be publicly available.

Language model query generation is the task of using a language model to translate a natural-language request into a formal query, which is then executed to retrieve information from databases or knowledge graphs. Recent approaches rely on reinforcement learning (RL) to enhance the model’s reasoning and improve query correctness. However, existing methods provide only sequence-level rewards, resulting in sparse feedback that is difficult to optimize. To address this limitation, we propose a reward shaping method that learns a token-level, and thus dense, reward function, providing fine-grained supervision to guide the language model toward correct queries. We formulate this problem as a bilevel optimization problem where the upper level learns a token-level shaping reward from ground truth sequence-level reward and the lower level optimizes the language model using the learned shaping reward. We propose a single-loop algorithm to solve this problem and theoretically guarantee that the algorithm converges at $O(\frac{1}{\sqrt{K}})+O(\frac{\log K}{\sqrt{K}})$. Extensive experiments demonstrate that our method outperforms the baselines.

For most of scientific history, researchers studying behavior could only infer hidden mechanisms from outward actions—an inverse problem that becomes more tractable when observation is augmented by targeted intervention. We pose a computational analogue: given only behavioral traces of an agent in a game environment, can a learner reconstruct the underlying decision program as executable code, and how much does this reconstruction improve with the ability to design controlled experiments? We introduce RevengeBench, a benchmark of 75 LLM generated, Elo-calibrated policies across five game environments, drawn from CodeClash tournament trajectories. The learner observes the hidden target policy play against sampled opponents and designs behavioral probes in the form of custom opponent policies that elicit informative behavior. It then submits an executable hypothesis, which is evaluated using continuous action-distance metrics. We further validate that recovered code carries informative signal in downstream player-versus-player tournaments. Across twelve frontier LLMs, recovery quality varies substantially (34–72\% of initial distance closed), with reconstructed policies yielding measurable competitive advantage, particularly for weaker models that otherwise struggle to design effective counter-strategies. Our benchmark positions behavioral recovery of programmatic policies as a tractable inverse problem in code-space, opening a path to opponent modeling, policy interpretability, and the broader question of inferring latent mechanisms from observations.

Aligning large language models (LLMs) to diverse user preferences is fundamentally hindered by standard alignment paradigms that optimize for monolithic users. In this work, through empirical studies, we first discover a massive, untapped performance headroom for personalized generation through test-time scaling. We demonstrate that personalized generation is uniquely suited for test-time sampling methods like Best-of-$N$ (BoN) because it can be viewed primarily as a candidate matching problem rather than a generator capability bottleneck. While standard reward models can theoretically exploit this headroom, their massive parameter counts introduce a prohibitive computational bottleneck. To overcome this limitation, we propose a parameter-efficient framework utilizing million-parameter scale Multi-Layer Perceptron (MLP) ranking models. Our personalized ranking model directly reuses the internal embeddings of the base generator with minimal overhead. By scaling train-time data to provide fine-grained personalized preferences, this million-parameter ranking model accurately scores large candidate pools and can seamlessly guide generation to reduce the cost of materializing $N$ candidates. Extensive experiments on nine datasets across three different personalized generation settings demonstrate that our framework effectively exploits the discovered headroom. Remarkably, our million-parameter MLP performs competitively with billion-parameter reward models explicitly finetuned on the same tasks, while requiring only a negligible fraction of the inference cost.