: Bridging 1D, 2D, and 3D
with Any-to-Any Multimodal Modeling

Jason Toskov1*, Oriol Barbany2*, Rishubh Singh1*, Jinya Sakurai1, Efe Tarhan1, Oğuzhan Fatih Kar4, Roman Bachmann4,
Amir Zadeh3, Jesse Allardice4, Chuan Li3, Carme Torras2, Afshin Dehghan4, Amir Zamir1

1 2 3 4

* Equal Contribution

We introduce , an any-to-any model that jointly processes a diverse set of 1D, 2D and 3D modalities. can predict any modality conditioned on any one (or multiple) other modalities, enabling cross-modality prediction across dimensionalities. The learned multimodal representations show strong performance on downstream tasks requiring both 2D and 3D understanding, including 3D pose prediction, grasp proposal, and object classification.

Overview

We present , an Omni-Dimensional Multimodal Foundation Model capable of any-to-any modelling across a diverse set of 1D, 2D and 3D modalities.

Our method enables any-to-any prediction across:

  • 1D: Captions, Metadata, Color palettes
  • 2D: RGB, Depth, Surface normals, Edges, Masks and Feature maps from DINOv2 and CLIP
  • 3D: Meshes, Gaussian splats, NeRFs, Voxels, UDFs, Bounding boxes and 3D Part features

This any-to-any prediction is enabled by a suite of novel tokenizers we delevop for 3D modalities, which enable masked modeling of 3D modalities in the same space as existing 1D and 2D modalities.

Our model is capable of a vast range of tasks out of the box beyond just the standard tasks of 3D generation from images. can perform generation steered by coarse input modalities, decompose objects into parts, retrieve views and objects and much more without any additional training.

Key Takeaways

Overview

Any-to-Any Generation

Our model can generate can generate any modality of any dimensionality from any other modality of any dimensionality, 1D, multi-view 2D or 3D. This enables all $n^2$ input-to-output tasks of the $n$ modalities to be performed with a single model.

Hover a row's input (leftmost column) to auto-play every modality generates from it.
Hover a single cell to inspect one task.

View

Object

# Modalities

Each cell is a different source to target prediction task, and all cells are generated by a single model. All 2D targets are multiview, which can be seen in the focused display next to the any-to-any grid. Our model is also capable of accepting multiple inputs, and so even this grid is only a subset of the possible tasks it can perform.

Method

A joint model over 1D, 2D, and 3D modalities

To enable multimodal modelling across dimensions, we unify the format of heterogenous modalities by casting them as discrete tokens, which can be jointly modelled with a multimodal masked modelling objective.

01Data

20 Diverse Modalities

can operate across 20 modalities, 3 multi-level and multi-type 1D modalities, 8 multi-view 2D modalities, and 9 3D modalities. These modalities are rendered and pseudo-labelled from meshes, removing the need for a multimodal 3D data source.

1D

Text-like data

2D

Single/multi-view image

3D

Complete 3D models

02Tokenization

A suite of 7 new 3D tokenizers

By unifying the representation of our data into a shared token space, we can make any-to-any prediction for any input and output tractable regardless of data dimensionality or modality. As tokenizers do not exist for many 3D modalities, we develop our own novel tokenizer architectures for 7 3D modalities.

Tokenizing 3D as dense 2D

Tokenizing 3D as dense 3D

Tokenizing multiview 2D

NeRF weights and part features can be represented as triplanes of features, each consisting of 3 dense multi-channel 2D feature tensors. We tokenize these triplanes using a modality-specific ViT-based VQ-VAE tokenizer.

3DGSs can be decoded from a sparse 3D SLAT which encodes high-fidelity 3D details. We densify SLATs via zero padding to obtain a dense 3D grid. Voxels, UDFs and NeRF grids are cast as dense 3D grids representing occupancy, distance to surface and RGB/density respectively, tokenized with a 3D convolutional VQ-VAE.

2D modalities are obtained from renders and tokenized with pre-existing tokenizers, with finetuning when necessary. We extract camera plucker rays from the rendering pipeline to help with modelling.

3D tokenizer reconstruction quality

The 7 tokenizers introduced by reconstruct their 3D modalities geometrically accurately and to a high level of detail.

Sample

Sample Crystals, 1 of 5

Voxels, UDFs, 3DGSs and 3D Grids are 3D modalities tokenized as dense 3D, while NeRF weights and Partfield features are 3D modalities tokenized as dense 2D. ULIP Embedding, here represented as its PCA reduced feature vector, is tokenized by an MLP-based tokenizer model.

03Modelling

The model architecture

is a 1 billion parameter transformer encoder-decoder. To perform joint learning on a range of 1D, 2D and 3D modalities, we optimize with the multimodal masked modeling objective introduced in 4M. The tokenized modalities are augmented with a positional embedding corresponding to their structure. We use 2D sin-cos embeddings for 3D modalities cast as dense 2D, 3D sin-cos embeddings for 3D modalities cast as dense 3D and encoded plucker rays are used for multiview 2D modalities.

The model

Diverse cross-modality generation capabilities

As is capable of accepting any combination of modalities both as inputs or outputs, it is capable of performing any prediction or generation task that uses any of the 20 modalities it was trained on. Below we show some of the possible tasks our model can do, but these are only a very small subset of our model’s capabilities.

Capabilities

Generation from 2D

can generate anything from any of the 8 2D modalities it was trained with. This enables the standard Novel View Synthesis (NVS) and 3D generation tasks to be greatly expanded to operate under any modality constraints.

Image-to-3D generation

can take a single image and lift it into any of the 9 3D modalities our model was trained with. This image input can also be a real world image when paired with an approach to segment out the target object.

One RGB input Nine 3D modalities
RGB
Rotary phone RGB input

BBox

Rotary phone BBox generation

Voxels

Rotary phone Voxels generation

UDF

Rotary phone UDF generation

3D Grid

Rotary phone 3D Grid generation

Mesh

Rotary phone Mesh generation

Partfield

Rotary phone Partfield generation

NeRF

Rotary phone NeRF generation

3DGS

Rotary phone 3DGS generation

ULIP

Rotary phone ULIP retrieval result Retrieval preview

NVS and 3D generations in different modalities

Our model can perform novel view synthesis within the space of any 2D modality, or any other 2D modality if an input is first translated to that modality. At any point, these 2D generations can be converted into a 3D model of any kind, which will respect the constraints introduced by the novel view synthesis generations.

Click to load the 3D models for that row.
RGBRGB modality generation
RGB novel view 1
RGB novel view 2
RGB novel view 3
RGB novel view 4
RGB novel view 5
RGB novel view 6
RGB novel view 7
RGB novel view 8
RGB 3DGS output
RGB Mesh output
RGB Voxels output
DepthDepth modality generation
Depth novel view 1
Depth novel view 2
Depth novel view 3
Depth novel view 4
Depth novel view 5
Depth novel view 6
Depth novel view 7
Depth novel view 8
Depth 3DGS output
Depth Mesh output
Depth Voxels output
EdgesEdges modality generation
Edges novel view 1
Edges novel view 2
Edges novel view 3
Edges novel view 4
Edges novel view 5
Edges novel view 6
Edges novel view 7
Edges novel view 8
Edges 3DGS output
Edges Mesh output
Edges Voxels output
NormalsSurface normals modality generation
Surface normals novel view 1
Surface normals novel view 2
Surface normals novel view 3
Surface normals novel view 4
Surface normals novel view 5
Surface normals novel view 6
Surface normals novel view 7
Surface normals novel view 8
Surface normals 3DGS output
Surface normals Mesh output
Surface normals Voxels output
MaskMask modality generation
Mask novel view 1
Mask novel view 2
Mask novel view 3
Mask novel view 4
Mask novel view 5
Mask novel view 6
Mask novel view 7
Mask novel view 8
Mask 3DGS output
Mask Mesh output
Mask Voxels output

RGB image inputs can be translated into other 2D modalities by our model. Novel view synthesis can then be performed in the new modality over arbitrary camera trajectories. When 3D is generated the properties of the novel views will be respected, such as colour and geometry.

Capabilities

Chained generation

As is an any-to-any model, outputs it generates can be passed back to the model to be used as conditioning for generation of other modalities or views of modalities in a process known as chaining.

RGB input
RGB input image of a bathtub
DINOv2
Surface Normals
RGB
Mesh
3DGS

Chained generation is when generated views or modalities are passed back to the model as additional conditioning for future generation. Here the chain involves the following: 1. The first DINOv2 view is generated conditioned on only the RGB input. 2. The following DINOv2 views are conditioned on the input, this generated DINOv2 view and any other DINOv2 views that have also been generated. 3. The surface normals and RGB views are similarly generated on all modalities and views generated before in addition to the original input. 4. The 3D modalities are generated conditioned on the complete set of input and chained 2D modalities.

Chaining for increased quality

Chaining can help improve 's performance on challenging tasks such as 3D generation from a single view input by routing generation though a series of more achievable tasks, rather than forcing zero-shot performance of the task. The benefits of chaining are in general most pronounced when coarser modalities are generated earlier, and details are incrementally built up through modalities. particularly benefits from chaining for generation of complex 3D geometry, where novel view synthesis gives a strong multi-view signal for accurate reconstruction of 3D geometry.

Generation
conditioning
Generated
3DGS
RGB input
RGB input image of a bathtub
Generated
DINOv2 NVS
Generated DINOv2 NVS view 3 Generated DINOv2 NVS view 5 Generated DINOv2 NVS view 8 Generated DINOv2 NVS view 19 Generated DINOv2 NVS view 10
Generated Surface
Normals NVS
Generated Surface Normals NVS view 3 Generated Surface Normals NVS view 5 Generated Surface Normals NVS view 8 Generated Surface Normals NVS view 19 Generated Surface Normals NVS view 10
Generated
RGB NVS
Generated RGB NVS view 3 Generated RGB NVS view 5 Generated RGB NVS view 8 Generated RGB NVS view 19 Generated RGB NVS view 10
Generated
Mesh Geometry

Chaining improves the performance of 3D generation from a single view for challenging inputs. Here each added chaining stage improves the quality of the final 3D model, making it closer to the ground truth model.

Chaining for generation consistency

Many conditioning modalities and cases are very under-constrained in terms of the objects that could have given rise to them. These might include caption that only semantically describe an object at a high level, weak geometry constraints such as 3D bounding boxes and voxels, or input views that leave aspects of an object ambiguous.

If performing unchained, direct generation our model can utilise this ambiguity to generate a diverse distribution of other views and modalities that fit the input constraint. Conversely, can perform chained generation to allow each new generated output to further constrain the generation conditioning. This leads to consistency across modalities and views, with one potential sample from the distribution gradually chosen as more constraining information is added to the conditioning.

Unchained generation
Unchained generated view 1
Unchained generated view 2
Unchained generated view 3
Unchained generated view 4
Unchained generated view 5
Unchained generated view 6
Unchained generated view 7
Unchained generated view 8
Chained generation
Chained generated view 1
Chained generated view 2
Chained generated view 3
Chained generated view 4
Chained generated view 5
Chained generated view 6
Chained generated view 7
Chained generated view 8
Unchained generation
RGB input
Mask
Chained generation
Inputs (Chained)
Mask

Left: Unchained generation predicts each modality and view independently, enabling diversity in outputs. Right: Chained generation constrains outputs to follow all previously generated modalities and views, resulting in consistency between past and future generations.

Capabilities

Generation from 3D

can also generate anything from any of the 9 3D modalities it was trained with. This enables both a range of new generation tasks and for many existing tasks involving 3D data to be simplified to a single forward pass of our model.

Using a Multimodal Model as a Renderer

Our model can render any view of any 2D modality from any 3D modality. Even if the 3D modality is untextured, can infer a reasonable texture to apply to the renders.

Every output cell cycles through the same 8 generated views.
Triplane
Triplane input
RGB rendered from the Triplane input
RGB
Depth rendered from the Triplane input
Depth
DINOv2 rendered from the Triplane input
DINOv2
Edges rendered from the Triplane input
Edges
Normals rendered from the Triplane input
Normals
CLIP rendered from the Triplane input
CLIP
3DGS
3DGS input
RGB rendered from the 3DGS input
RGB
Depth rendered from the 3DGS input
Depth
DINOv2 rendered from the 3DGS input
DINOv2
Edges rendered from the 3DGS input
Edges
Normals rendered from the 3DGS input
Normals
CLIP rendered from the 3DGS input
CLIP
Mesh
Mesh input
RGB rendered from the Mesh input
RGB
Depth rendered from the Mesh input
Depth
DINOv2 rendered from the Mesh input
DINOv2
Edges rendered from the Mesh input
Edges
Normals rendered from the Mesh input
Normals
CLIP rendered from the Mesh input
CLIP

Using a Multimodal Model for Texturing

We can also directly apply textures to 3D models instead by generating novel views and textured 3D models jointly conditioned on an untextured 3D modality and a colour palette.

Mesh input

Click on a row to load its 3DGS.

Capabilities

Steerable Generation

can steer the generation of 2D and 3D modalities from text by jointly conditioning on a weak geometric restriction. This enables objects with specific geometric characteristics to be generated.

Weak 2D and 3D shape conditioned generation

Objects generated from more specified restrictions such as voxels or masks strongly follow the geometric constraints, while adapting the texture and content of the object to fit the caption conditioned on.

Steerable generation from voxels

Steerable generation from masks

Generation within size constraints

Objects generated from a weaker constraint such as conforming to a specific bounding box size along a given axis have freedom to generate with more diversity, while consistently satisfying the constraint.

Drag a slider, or click to load that mesh.

Requested bounding box
Generated mesh

Requested bounding box
Generated mesh

Requested bounding box
Generated mesh

Requested bounding box
Generated mesh

Left: Objects constrained in the x, y and z axis. Right: The generated fountain takes on different forms when constrained to different extreme axis lengths.

Capabilities

Object decomposition

We can use the multi-level understanding of object parts that our model can produce via it’s part feature modality to both split existing 3D models into parts, or generate our own 3D models which can then be segmented to different levels of part granularity.

PartField input

RGB

Mesh

Part features

Decomposed mesh

Sample

Sample Hydrant, 3 of 6

# parts: 4

Explode

From a single RGB image we can generate both a full object model and its corresponding multi-level part features. These part features can then be clustered to different numbers of parts and applied to the generated model to segment it.

Capabilities

Retrieval

Our model can use any modality as a query to generate DINOv2 and ULIP-2 features, which can be used for retrieval across modalities and dimensions.

Shape-based (ULIP-2) Retrieval

View-dependent (DINOv2) Retrieval

ULIP-2 features are global features that align object point cloud features with the CLIP features derived from renders and associated captions of multiple views of the mesh which generated the point cloud. As such, it can be used to query for similar objects across modalities, independent of view.

DINOv2 features can be used to query for similar views across modalities that also contain similar semantic content. Use the arrows to move the query view to explore this matching.

Benchmarks

Qualitative Results

Geometrically accurate 3D generation

generates geometrically consistent 3D outputs from a single view, matching or outperforming existing specialized methods.

3D generation single-view input

RGB

SAM3D

TRELLIS

Ours

GT

Sample

Sample Bathtub, 1 of 3

Quantitative Results

Single-View 3D Generation

For single-view 3D generation, we compare the quality and consistency of reconstructed outputs against established specialized methods.

Dataset GSO Google Scanned Objects

Bold, shaded cells are best in their metric; underlined values are second-best. Rows marked (Chained) use chained generation.

Quantitative Results

2D Novel View Synthesis

Starting from a single input view, we evaluate the quality and perceptual consistency of images rendered from unseen viewpoints.

Dataset GSO Google Scanned Objects

Bold, shaded cells are best in their metric; underlined values are second-best. Rows marked (Chained) use chained generation.

Transfers to novel tasks

transfers multimodal representations to downstream tasks and acts as a strong representation capable of transferring to tasks that require both 2D and 3D understanding.

Open release

Model checkpoints

We release both a core any-to-any model which is capable of performing all tasks, and a RGB generation specialist which is capable of generating the highest quality RGB outputs.

Core any-to-any
-1B-a2a-20mod

The core model, capable of any-to-any tasks using all 20 modalities.

View on Hugging Face
Image generation expert
-1B-RGBGenFT

specialized to generate high-quality RGB from any input modalities.

View on Hugging Face

Tokenizer checkpoints

We also release our full suite of novel 3D tokenizers and fine-tuned 2D tokenizers. We hope that this will help further the research of multimodal 3D research by providing an easily adaptable input format for a range of 3D modalities.

UDF Tokenizer
-Tok-UDF-64

UDF 3D Grid VQ-VAE tokenizer with no distance truncation.

Link
UDF modality preview
Voxel Grid Tokenizer
-Tok-Voxel-32

Voxel Grid VQ-VAE tokenizer learned with MSE loss.

Link
Voxels modality preview
3D RGB/Density Grid Tokenizer
-Tok-3DGrid-64

Joint 3D RGB/Density Grid VQ-VAE tokenizer.

Link
3D Grid modality preview
NeRF Weight Tokenizer
-Tok-NeRF-64

NeRF Weight VQ-VAE triplane tokenizer.

Link
NeRF modality preview
Partfield Feature Tokenizer
-Tok-Parts-128

Partfield Feature VQ-VAE triplane tokenizer.

Link
Partfield modality preview
ULIP-2 Tokenizer
-Tok-ULIP2-MLP

Point cloud ULIP-2 feature MLP tokenizer.

Link
ULIP modality preview
Latent 3DGS Tokenizer
-Tok-3DGS-Conv

3DGS latent tokenizer with an occupancy head, learned with rendering losses.

Link
Mars rover render from the Trellis convolutional tokenizer
Latent 3DGS Tokenizer
-Tok-3DGS-Flow

3DGS latent tokenizer with a flow decoder, for smoothed token interpolation.

Link
Mars rover render from the Trellis flow tokenizer
Object Image Tokenizers
-Tok-Normals-4MFT & -Tok-Mask-4MFT

Finetuned Surface Normals & Mask 4M tokenizers to adapt to objects.

Link