surrogatemodels
Reference and tools/CataloguesCore

Ten families at a glance.

In one lineTen surrogate families at a glance, grouped by the data they consume.

Scalar models predict a few numbers; full-field models predict the whole field.

10 models
Scalar & reduced-order

Gaussian process (Kriging)

A handful of design parameters → one or a few scalars

A probabilistic regression over the design space: every prediction comes with an uncertainty estimate.

Strengths & limits
Good for
Small datasets, Bayesian optimisation, knowing when the model is unsure.
Watch out
Scales poorly with the number of samples and parameters, and does not predict fields.
Sacks, Welch, Mitchell & Wynn, Statistical Science, 1989
Scalar & reduced-order

POD reduced-order model

Fields on a fixed mesh

Snapshots are compressed onto a few dominant modes (POD/PCA); a regression model predicts the mode coefficients.

Strengths & limits
Good for
Parametric studies on one fixed mesh, fast and interpretable.
Watch out
Needs a common mesh across designs and struggles when the geometry changes topology.
Benner, Gugercin & Willcox, SIAM Review, 2015
Grid / voxel

U-Net (CNN)

Voxel or pixel grids: SDF or occupancy in, field out

Convolutional encoder–decoder with skip connections between matching resolutions.

Strengths & limits
Good for
Fields on regular grids; robust and easy to train. Used early on for RANS airfoil flows.
Watch out
Fixed resolution; memory grows with N³; geometry detail is lost below voxel size.
Ronneberger et al., MICCAI 2015 · applied to RANS: Thuerey et al., AIAA Journal 2020
Grid / voxel

Fourier Neural Operator

Functions sampled on a regular grid

Layers mix information globally by learning weights on the lowest Fourier modes of the field.

Strengths & limits
Good for
Smooth, global PDE solutions; can be evaluated at resolutions it was not trained on.
Watch out
Native form needs a regular grid; sharp features need many modes.
Li et al., ICLR 2021
Graph

MeshGraphNets

Simulation mesh as a graph (nodes + edges)

Encode–process–decode: message passing along mesh edges, one hop per layer.

Strengths & limits
Good for
Unstructured meshes, complex geometry, transient simulation by rollout.
Watch out
Long-range effects need many layers or multiscale graphs; cost grows with mesh size.
Pfaff, Fortunato, Sanchez-Gonzalez & Battaglia, ICLR 2021
Graph

Graph Network Simulator

Particles with neighbour graphs rebuilt every step

Learns particle accelerations by message passing, then integrates in time.

Strengths & limits
Good for
Fluids, granular media and deformables represented as particles.
Watch out
Long rollouts accumulate error; neighbour search every step.
Sanchez-Gonzalez et al., ICML 2020
Point cloud

PointNet

Unordered points (x, y, z, normals…)

A shared MLP per point plus a symmetric global pooling, so point order does not matter.

Strengths & limits
Good for
A simple baseline for geometry-to-field prediction on raw points.
Watch out
Weak at local structure unless extended (PointNet++).
Qi, Su, Mo & Guibas, CVPR 2017
Point cloud

GINO

Point cloud or mesh → latent regular grid → points

A graph neural operator maps points onto a latent grid, an FNO works there, and a second graph operator maps back.

Strengths & limits
Good for
Large 3D geometries, such as full car aerodynamics, at fixed cost per latent grid.
Watch out
Two-stage architecture with more pieces to tune.
Li et al., NeurIPS 2023
Point cloud

Transolver

Points from any mesh or point cloud

Physics-attention: points are softly grouped into learned slices, attention runs between slice tokens, results broadcast back to points.

Strengths & limits
Good for
Large unstructured geometries with linear cost in the number of points; strong across PDE benchmarks.
Watch out
Slices are learned, so their meaning is not guaranteed to be physical.
Wu, Luo, Wang, Wang & Long, ICML 2024
Operator learning

DeepONet

Input function at sensor points + query coordinates

A branch net encodes the input function, a trunk net encodes where to evaluate; their dot product is the output.

Strengths & limits
Good for
Evaluating the field at arbitrary query points; theory-backed operator learning.
Watch out
Needs input functions sampled at fixed sensor locations in its basic form.
Lu, Jin, Pang, Zhang & Karniadakis, Nature Machine Intelligence, 2021

Reference and tools/CataloguesCore

The technique library.

In one lineThirty techniques that make surrogates work in practice, from basics to the frontier.

Classical and deep techniques, filterable by depth and by topic.

Depth
13 techniques
Basics Data & sampling

Design of experiments

Latin hypercube, Sobol sequences or maximin designs spread simulations evenly over the design space.

+ why it matters
Basics Architecture

Response surfaces & kriging

Polynomial regression and Gaussian-process interpolation over a few design parameters.

+ why it matters
Basics Training

Input & output normalisation

Scale coordinates, parameters and fields to unit range; predict non-dimensional quantities (e.g. a pressure coefficient rather than pascals).

+ why it matters
Basics Uncertainty & trust

Hold-out & cross-validation

Measure RMSE, relative L2 and R² on designs never used in training, by k-fold or a fixed hold-out set.

+ why it matters
Basics Geometry & inputs

Signed distance & normals

Give each point its distance to the wall and the surface normal as input features.

+ why it matters
Basics Architecture

Encode–process–decode

Lift inputs to an embedding, process with a stack of blocks, read out the field.

+ why it matters
Core Geometry & inputs

Fourier features

Map coordinates through sines and cosines at several frequencies before the first layer.

+ why it matters
Core Architecture

Message passing

Each node updates from aggregated messages of its neighbours, one hop per layer.

+ why it matters
Core Architecture

Spectral convolution

Learned filters on the lowest Fourier modes of the field.

+ why it matters
Core Architecture

Multiscale hierarchies

Coarsen the grid, graph or point set, process, and refine with skip connections.

+ why it matters
Core Architecture

Self- & cross-attention

Tokens weight each other by query–key similarity; cross-attention reads one set from another.

+ why it matters
Core Training

Noise injection for rollout

Corrupt inputs with noise during training of time-stepping models.

+ why it matters
Core Architecture

Reduced-order models (POD)

Compress snapshots onto a few dominant modes and regress the mode coefficients.

+ why it matters

Reference and tools/ResearchAdvanced

Four lineages, from the basics to 2026.

In one lineFour families of field surrogates, from their founding idea to 2026.

Each family of full-field surrogates grew from a foundational idea. Hover the timeline to follow how each one evolved.

Physical view → Nodes are mesh points and edges the mesh connectivity, so resolution follows the physics: fine near walls and shocks, coarse far away.

2020202220242026
ICML 2020 Basics

GNS

Message passing on particle neighbourhoods; noise injection keeps long rollouts stable.

paper ↗
ICLR 2021 Core

MeshGraphNets

Encode–process–decode on simulation meshes, with mesh-space and world-space edges.

paper ↗
ICML workshop 2022 Advanced

Multiscale MGN

Coarse graph levels carry information across the domain in fewer layers.

paper ↗
ICML 2023 Advanced

BSMS-GNN

Bi-stride pooling builds multiscale graphs automatically, without hand-made coarse meshes.

paper ↗
NeurIPS 2025 Frontier

GAOT

Multiscale attentional graph encoder and decoder around a transformer processor.

paper ↗
arXiv 2026 Frontier

GIST

Spectral embeddings of mesh connectivity for tightly packed geometries such as race cars.

paper ↗

Reference and tools/ResearchFrontier

Where the field is heading.

In one lineMore field-surrogate architectures from NeurIPS, ICML and ICLR, 2023 to 2026, in order; the explained highlights are on Papers.

The trend: encode any geometry into a compact latent space, process it with attention, and decode anywhere, at million-cell scale.

A longer reading list, with one line per paper. The papers that shaped the field, each explained with what it changed and the lesson that prepares you for it, are on Papers; to read any of them critically, see reading a surrogate paper.

24 papers · 2023 → 2026
NeurIPS 2024

UPT

Fixed-size latent space; perceiver encoder; latent rollout

paper ↗
ICML 2024

Transolver

Physics-attention over learned slices

paper ↗
ICML 2023

GNOT

Heterogeneous normalised cross-attention, linear complexity

paper ↗
NeurIPS 2023

GINO

Graph operator to a latent grid, FNO there, graph operator back

paper ↗

Reference and tools/ResearchBasics

Seventy years of surrogates.

In one lineSeventy years from response surfaces and kriging to neural fields on any geometry.

The idea is old: replace an expensive experiment or simulation with a cheap fitted model. What changed is what the model can predict, from a single number to the full field on any geometry.

1951

Response surfaces

Box & Wilson fit low-order polynomials to experiments: the first surrogate models, still used in design of experiments.

1960s–80s

Kriging

Gaussian-process interpolation from geostatistics: a surrogate that also says how uncertain it is.

1990s–2000s

Design optimisation

Kriging, radial basis functions and POD reduced-order models enter aerospace and automotive design loops.

2015–20

Deep learning on grids

Convolutional U-Nets predict full flow fields on images and voxel grids; physics-informed networks appear.

2020–23

Geometry-native models

Graph networks on simulation meshes, point-cloud networks and neural operators learn directly on engineering geometry.

2024–26

Transformers and foundation models

Latent-token transformers scale to 100M-cell CFD; pretrained physics models fine-tune to new problems with little data.


Reference and tools/Build your ownCore

You don't start from scratch.

In one lineWhere to start in code: open neural frameworks, plus classical surrogate and UQ toolkits.

Open implementations of the models, data pipelines and training recipes that most industrial surrogates build on.

5 entries
NVIDIAApache-2.0

PhysicsNeMo

A PyTorch framework for training and deploying physics-ML models on simulation data, from data loading to multi-GPU training. Formerly NVIDIA Modulus.

MeshGraphNet, Transolver, FNO, DoMINO, diffusion models, PINNs; reference examples for external aerodynamics

github.com/NVIDIA/physicsnemo ↗
Caltech / NVIDIA (PyTorch Ecosystem)MIT

NeuralOperator

The reference library for neural operators: models that map between functions and work across discretisations.

FNO, tensorised FNO, U-shaped NO, GINO; data loaders and losses for PDE benchmarks

github.com/neuraloperator/neuraloperator ↗
THUML, Tsinghua University

Neural-Solver-Library

A library of neural PDE solvers from the authors of Transolver, with unified benchmarks for comparing architectures.

Transolver and many baselines on standard and industrial-geometry benchmarks

github.com/thuml/Neural-Solver-Library ↗
Lu Lu et al.

DeepXDE

Physics-informed neural networks and operator learning, with PyTorch, JAX and TensorFlow backends.

PINNs, DeepONet, inverse problems

github.com/lululxvi/deepxde ↗
PyG teamMIT

PyTorch Geometric

General-purpose graph neural network building blocks, often used to assemble mesh-based surrogates.

Message-passing layers, graph pooling, mesh and point-cloud utilities

github.com/pyg-team/pytorch_geometric ↗

Reference and tools/Build your ownCore

Data to learn from.

In one linePublic simulation datasets to benchmark on before you have your own.

Public simulation datasets are how new architectures are compared, and a starting point before you have your own. Check the licence: several are non-commercial.

7 entries
Bonnet et al., NeurIPS 2022ODbL-1.0

AirfRANS

Over 1,000 2D airfoils simulated with steady RANS in OpenFOAM: full volume and surface fields.

Airfoil aerodynamics, the 2D analogue of this page

github.com/Extrality/AirfRANS ↗
Ashton et al., 2024CC BY-SA

DrivAerML

500 parametric variants of the DrivAer car simulated with high-fidelity hybrid RANS-LES.

Road-car external aerodynamics; permits commercial use

caemldatasets.org/drivaerml ↗
Elrefaie et al., MITCC BY-NC 4.0

DrivAerNet++

8,000 diverse car designs with CFD results, geometry and performance data.

Large-scale car aerodynamics; non-commercial (commercial licences offered separately)

github.com/Mohamedelrefaie/DrivAerNet ↗
Ashton et al., 2026CC-BY-4.0

HiLiftAeroML

1,800 wall-modelled LES runs of 180 variants of the NASA CRM high-lift aircraft, at ten angles of attack from 4° to 22°, on grids of 300 to 500 million cells, compared with wind-tunnel data.

High-lift aircraft aerodynamics, attached to post-stall; used by AeroJEPA and CANTO

arxiv.org/abs/2605.19565 ↗
Ashton et al., 2024

AhmedML

500 variants of the Ahmed body, the classic bluff-body benchmark, with hybrid RANS-LES.

Low-speed bluff-body aerodynamics

caemldatasets.org/ahmedml ↗
Takamoto et al., NeurIPS 2022

PDEBench

A benchmark suite of PDE datasets and baselines for scientific machine learning.

Advection, Burgers, Navier–Stokes, reaction–diffusion and more

github.com/pdebench/PDEBench ↗
Polymathic AI, NeurIPS 2024

The Well

A very large collection of physics simulation datasets spanning fluids, plasmas, astrophysics and biology.

Multi-physics data for training general-purpose and foundation models

github.com/PolymathicAI/the_well ↗

Reference and tools/Build your ownBasics

From open source to your own surrogate.

In one lineFrom open frameworks and datasets to a surrogate trained on your own simulations.

Four steps, from public data and reference code to a model fitted to your own product.

Pick data close to your physics

Start from an open dataset in the same regime (external aero, internal flow, thermal), or your own simulation archive.

AirfRANSDrivAerMLThe Well
Start from a reference model

Frameworks ship tested implementations and training recipes; reproduce a published baseline before changing anything.

PhysicsNeMoNeuralOperatorPyG
Validate on held-out designs

Measure error on designs never seen in training, and report the training range alongside every prediction.

Held-out designsError mapsConformal bands
Fine-tune on your own cases

Adapt a pretrained model to your product line with a smaller set of your own simulations.

Pretrained weightsYour simulationsFew-shot

The surrogate on this site is a deliberately small neural field (6,337 weights) so it can be explained end to end. Industrial models are larger (graph, transformer or operator architectures trained on thousands of high-fidelity runs), but the workflow is the same.