Multiview Diffusion Models

• Multiview diffusion models are generative frameworks that synthesize coherent sets of images across different viewpoints using iterative denoising and geometric priors.
• They employ specialized attention mechanisms, such as correspondence-aware and epipolar-constrained attention, to ensure photometric and geometric consistency.
• Advances in these models improve scalability and performance for diverse applications including 3D reconstruction, 4D dynamic content creation, and appearance transfer.

Multiview diffusion models are a class of generative models that synthesize sets of images corresponding to multiple viewpoints of a scene or object while enforcing geometric and photometric consistency. These models are constructed atop the denoising diffusion probabilistic framework and integrate cross-view mechanisms—often via specialized attention, geometric priors, or correspondence structures—to produce outputs suitable for downstream 3D tasks. Recent innovations have significantly improved multiview consistency, scalability, and applicability to difficult domains such as human portrait synthesis, 4D video, and appearance transfer. This article surveys multiview diffusion models, focusing on architectures, geometric mechanisms, training objectives, and quantitative performance.

1. Probabilistic Formulation and Model Architectures

Multiview diffusion models generalize the classical DDPM paradigm by operating over multiview latent stacks rather than single images. Given a set of $N$ views—with optionally known or fixed camera poses—models predict, via iterative denoising, a coherent set of latent representations $\{z^{(k)}\}_{k=1}^N$ that decode into RGB images or explicit geometric assets.

Architectures typically extend a base U-Net or transformer backbone:

• Parallel latent stacks: Inputs are encoded as $N$ noisy latent tensors processed jointly or concurrently (Tang et al., 2023).
• Cross-view and correspondence-aware attention: Mechanisms enable feature sharing and structural alignment between view branches, conditioning denoising on geometric and textural cues shared across perspectives (Huang et al., 2023, Tang et al., 2023).
• Geometric prior integration: Structured representations such as normalized object coordinate maps, explicit pointmaps, or mesh-based conditioning enforce geometric alignment and facilitate downstream reconstruction (Kabra et al., 2024, Wang et al., 11 Mar 2025).

Some methods, such as unPIC, adopt a hierarchical architecture with a “prior” stage that predicts geometry features followed by a “decoder” that generates images conditioned on those priors (Kabra et al., 2024). Others fuse input views with retrieval image tokens or utilize explicit identity or style embeddings for specialized tasks (Galanakis et al., 14 Apr 2025, Dayani et al., 22 Aug 2025).

2. Geometric and Multiview Consistency Mechanisms

Ensuring consistency across output views is a central technical challenge. Approaches include:

• Correspondence-Aware Attention (CAA): Pixel-to-pixel or region-based mappings are leveraged via attention kernels that explicitly align features with their geometric correspondences across views. This is critical for panorama generation and depth-to-image synthesis (Tang et al., 2023, Theiss et al., 2024).
• Epipolar-Constrained Attention: EpiDiff introduces attention modules constrained by stereo geometry, restricting cross-view feature aggregation to plausible epipolar lines. This enforces physically motivated feature fusion without requiring global volumetric modeling, thus reducing overfitting and boosting inference speed (Huang et al., 2023, Bourigault et al., 2024).
• Mesh Attention for High Resolution: MEAT replaces $O(N^2S^4)$ multiview dense attention with rasterization and mesh-driven projection, allowing 1024x1024 training and efficient cross-view matching (Wang et al., 11 Mar 2025).
• Camera-Relative Embeddings (CROCS): Camera-rotated object coordinate maps disambiguate per-view color encoding, facilitating cyclic geometric priors robust to azimuthal rotation (Kabra et al., 2024).
• Fourier-Based Attention and Noise Initialization: Time-dependent frequency-domain blocks propagate low-frequency consistency across non-overlapping regions, while coordinate-based noise initialization seeds consistent spatial layouts in panoramic and multiview scenarios (Theiss et al., 2024).

3. Training Objectives, Losses, and Regularization

The principal training objective remains the $\ell_2$ denoising score matching loss on all views’ latent stacks. Augmentations include:

• Epipolar and reconstruction losses: Penalize deviations from geometric constraints or from downstream reconstructions (Bourigault et al., 2024, Kabra et al., 2024).
• Cross-attention and appearance transfer: FROMAT demonstrates few-shot adaptation of layer-wise self-attention parameters to transfer materials or styles between object and appearance streams, optimizing only a small set of mixing weights (Kompanowski et al., 10 Dec 2025).
• Human-aligned rewards and preference learning: MVReward trains a BLIP/VIT-backed reward function to align generated assets with human preferences, providing a scalar evaluation metric for model selection or plug-and-play fine-tuning (Wang et al., 2024).

Other regularization strategies include classifier-free guidance (dropping conditions to preserve generative diversity), interleaved multi-view attention layers, and latent feature smoothing to avoid geometric collapse in novel views.

4. Applications: 3D and 4D Synthesis, Editing, and Appearance Transfer

Multiview diffusion models constitute the backbone for a range of generative 3D and 4D workflows:

• Image-to-3D synthesis: Models such as unPIC and DSplats probabilistically hallucinate novel views given a single image, then reconstruct meshes or Gaussian splatting fields from synthesized images (Kabra et al., 2024, Miao et al., 2024).
• Text-driven and retrieval-conditioned generation: MV-RAG integrates large-scale image retrieval as conditioning to handle rare or OOD concepts, with hybrid training integrating view-augmented synthetic data and held-out real images (Dayani et al., 22 Aug 2025).
• Human synthesis at megapixel scale: MEAT achieves dense multiview generation for clothed humans, fusing high-res mesh-based attention and keypoint conditioning (Wang et al., 11 Mar 2025).
• Material and style transfer: FROMAT adapts few-shot appearance transfer across multiview human assets by mixing self-attention blocks of reference and object streams (Kompanowski et al., 10 Dec 2025).
• Dynamic 4D content creation: MVTokenFlow uses token-flow guided regeneration and 4D Gaussian field refinement to create temporally and spatially consistent dynamic assets from monocular videos (Huang et al., 17 Feb 2025).
• Source separation and scientific inference: A Data-Driven Prism demonstrates that diffusion-model priors can disentangle multiple latent sources from oversampled multiview observations by sampling from joint posteriors via score-based EM (Wagner-Carena et al., 6 Oct 2025).

5. Quantitative Performance and Evaluations

Standard evaluation criteria include PSNR, SSIM, LPIPS, FID, and CLIP scores over generated views or reconstructed assets. Results across prominent benchmarks establish clear SOTA trends:

Method	PSNR (dB)	SSIM	LPIPS	FID	CLIP
unPIC	23.86	0.79	—	—	—
DSplats	20.38	0.842	0.109	—	0.921
MEAT (human)	18.91	0.9271	0.0751	10.60	—
EpiDiff	20.49	0.855	0.128	—	—
SpinMeRound	SSIM 0.73	—	0.30	—	ID-sim 0.61

In OOD text-to-3D evaluation, MV-RAG outperforms baselines in CLIP, DINO, and retrieval similarity, demonstrating improved text adherence and multiview 3D consistency (Dayani et al., 22 Aug 2025). MVP tuning with MVReward yields perfect Spearman correlation with human judgment; ablations confirm the criticality of cross-view attention and prompt-aligned scoring modules (Wang et al., 2024).

6. Limitations, Open Problems, and Future Directions

Despite advances, key limitations persist:

• Data dependence and generalizability: Several approaches remain sensitive to the quality and variety of training data; domain drift and bias in depth estimation can yield artifacts in underrepresented viewpoints (Xiang et al., 2023).
• Memory and compute overhead: High-resolution mesh or dense attention models require extensive GPU resources; geometric inference at scale necessitates specialized approximations (e.g., mesh attention) (Wang et al., 11 Mar 2025).
• Incomplete end-to-end modeling: Many pipelines decouple multiview generation from explicit 3D asset recovery, introducing reconstruction errors; future architectures may directly fuse 3D feedback via score distillation or differentiable rendering (Huang et al., 2023).
• Timeliness and speed: Inference remains nontrivial for large view sets or 4D content editing; approaches such as Efficient-NeRF2NeRF’s correspondence regularization and mesh attention offer direction for acceleration (Song et al., 2023, Wang et al., 11 Mar 2025).

Promising future directions cited include model-based reward integration for human alignment (Wang et al., 2024), scale-out to arbitrarily posed video or panoramic content (Theiss et al., 2024), unified 4D spatiotemporal diffusion models (Huang et al., 17 Feb 2025), and robust geometric priors for out-of-domain generation (Dayani et al., 22 Aug 2025).

7. Theoretical Foundations and Mathematical Generalization

Beyond generative workflows, multiview diffusion geometry provides a formal lens for multi-view clustering, embedding, and manifold learning. Recent theory frames multi-view fusion as inhomogeneous Markov trajectory products—intertwined diffusion trajectories (MDT)—with explicit ergodicity and embedding properties, generalizing cross-view kernel fusion (Debaussart-Joniec et al., 1 Dec 2025). MultiView Diffusion Maps and MDTs deliver spectral embeddings robust to noise, partial views, and view-specific distortions; random MDTs serve as rigorous baselines for operator-based model comparison (Lindenbaum et al., 2015, Debaussart-Joniec et al., 1 Dec 2025).

In summary, multiview diffusion models constitute a high-impact union of generative modeling, geometric learning, and probabilistic theory, with diverse architectures and mechanisms enabling state-of-the-art performance in 3D/4D synthesis, editing, and scientific separation tasks. These models continue to drive innovation at the intersection of computer vision, graphics, and machine learning.