Accurate long-horizon prediction of spatiotemporal fields on complex geometries is a fundamental challenge in scientific machine learning, with applications such as additive manufacturing where temperature histories govern defect formation and mechanical properties. High-fidelity simulations are accurate but computationally costly, and despite recent advances, machine learning methods remain challenged by long-horizon temperature and gradient prediction. We propose a deep learning framework for predicting full temperature histories directly on meshes, conditioned on geometry and process parameters, while maintaining stability over thousands of time steps and generalizing across heterogeneous geometries. The framework adopts a temporal multiscale architecture composed of two coupled models operating at complementary time scales. Both models rely on a latent recurrent graph neural network to capture spatiotemporal dynamics on meshes, while a variational graph autoencoder provides a compact latent representation that reduces memory usage and improves training stability. Experiments on simulated powder bed fusion data demonstrate accurate and temporally stable long-horizon predictions across diverse geometries, outperforming existing baseline. Although evaluated in two dimensions, the framework is general and extensible to physics-driven systems with multiscale dynamics and to three-dimensional geometries.
Figures & tables
Figure 1: Example of printed geometry. Metallic powder is in gray, the final printed part is in blue and the part boundaries are highlighted in green.
Figure 2: Temperature field snapshots for a fixed printed geometry at multiple time steps. The green lines indicate the part boundaries, enclosing the solid metallic region. The temperature is simulated for both metallic part and the surrounding powder.
Figure 3: Overview of the LM-RGNN architecture and its main components, including the latent-RGNN and the VGAE.
Model
MAE (°C)
MAPE (%)
MME (°C)
mpIoU
MAE∇xy (°C/mm)
MAE∇t (°C/s)
Parameters
Interlayer
7.29 ± 0.17
4.48 ± 0.22
44.5 ± 0.5
2.10 ± 0.05
0.76 ± 0.09
85k
↪ w/o latent
17.80 ± 9.16
4.73 ± 1.57
95.0 ± 40.6
4.65 ± 1.54
0.40 ± 0.18
91k
Intralayer
6.48 ± 0.19
2.20 ± 0.010
108.7 ± 2.80
0.87 ± 0.0016
2.46 ± 0.030
1.61 ± 0.020
42k
↪ w/o latent
6.80 ± 0.34
2.43 ± 0.18
50.6 ± 2.0
0.91 ± 0.0081
2.27 ± 0.10
1.28 ± 0.064
41k
LM-RGNN
6.50 ± 0.10
2.58 ± 0.002
108.7 ± 0.28
0.85 ± 0.0017
2.44 ± 0.030
1.98 ± 0.0031
127k
↪ w/o latent & multiscale strategy
26.28 ± 1.45
7.25 ± 1.12
111.46 ± 5.1
0.69 ± 0.097
5.98 ± 1.30
7.13 ± 0.84
131k
Table 1: Comparison of performance metrics on the test set across the proposed models, their ablated variants (marked by the ↪ symbol) , and the baseline.
Model
Inference time (ms)
Mem. pressure
Interlayer
30.4
Low
↪ w/o latent
30.9
Medium
Intralayer
12.35
Low
↪ w/o latent
14.28
Medium
LM-RGNN
14.47
Low
↪ w/o latent & multiscale strategy
68.19
High
Table 2: Comparison of per-time-step inference time and training-time memory pressure across the proposed models, their ablated variants (marked by the ↪ symbol), and the baseline.
Figure 4: Temporal MAE (t-MAE) on the test set for the interlayer model, compared with its full-dimensional (non-latent) counterpart.
Figure 5: Temporal MAE (t-MAE) on the test set for the intralayer model, compared with its ablated variants.
Figure 6: Temporal MAE on the test set for the LM-RGNN model, compared with its ablated variant and the Decoupled-RGNN baseline.
Appendix figures & tables17 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 7: Geometry parametrization. w is the part base width, hl and hr are the heights of left and right line-breaks respectively, αl1 , αr1 , αl2 , αr2 are line angles.
Figure 8: Examples of generated geometry. Metallic powder is in gray, the final printed part is in blue and the part boundaries are highlighted in green.
Number of elements
Runtime
Number of time steps
mean
29987
1h 38m 37s
9316
std_dev
5756
0h 53m 13s
1341
min
18126
0h 20m 42s
6544
max
43670
3h 51m 2s
12523
Appendix
Table 3: Simulations statistics
Figure 9: Thermal domain at time t .
Figure 10: Thermo-physical properties used in the numerical model.
Figure 13: (a) VGAE encoder with depth d=3 . (b) VGAE decoder with depth d=3 .
GraphPool hidden size
32
GraphPool hidden layers
2
GraphUnpool hidden size
32
GraphPool hidden layers
2
Input features size
3 (temperature, mask, material mask)
Output features size
1 (temperature)
Encoder hidden size
12, 24, 32
Appendix
Table 4: VGAE hyper-parameters.
Interlayer latent RGNN
Intralayer latent RGNN
Hidden feature size
48
32
Geometry encoder: GraphPool hidden size
16
16
Geometry encoder: GraphPool hidden layers
2
2
Geometry encoder hidden size
8, 16, 16
8, 16, 16
Geometry encoder input features size
2
2
Geometry encoder output features size
16
16
Appendix
Table 5: Architecture details of the interlayer and intralayer models. The geometry encoder is used to encode geometrical inputs (active nodes mask, material mask) to the latent mesh. MPGNN denotes Message Passing Graph Neural Network and is used in the GraphGRU architecture.
Model
Learning rate
Batch size
LR warmup
LR scheduler
VGAE
1e-3
64
Yes
Cosine annealing ( Tmax=130 , ηmin=1e−4 )
Interlayer
2e-3
4
Yes
Cosine annealing ( Tmax=140 , ηmin=1e−5 )
Intralayer
4e-3
64
Yes
Cosine annealing ( Tmax=180 , ηmin=1e−5 )
Decoupled-RGNN
1e-3
4
Yes
Cosine annealing ( Tmax=130 , ηmin=1e−3 )
Appendix
Table 6: Training hyper-parameters. The LR warmup is a linear LR scheduler with start factor = 0.1 and duration = 8.
TBPTT steps
8
Early stopping patience
25
SOAP optimizer betas
0.95, 0.95
SOAP optimizer weight decay
0.01
SOAP optimizer preconditioning frequency
8
Appendix
Table 7: Training hyper-parameters with a fixed value.
Figure 14: The blue curve is the temporal MAE (t-MAE) on the test set for the VGAE with latent dim. 4. The red curve is the function f(t)=t-MAE(0)/domain size(t) .
Latent dim.
MAE (°C)
MAPE (%)
MME (°C)
mpIoU
MAE∇xy (°C/mm)
MAE∇t (°C/s)
Parameters
4
7.05 ± 1.68
2.44 ± 0.51
118.6 ± 22.5
0.86 ± 0.02
3.01 ± 0.30
3.68 ± 0.84
19.0k
8
5.74 ± 0.93
2.08 ± 0.31
98.3 ± 12.7
0.88 ± 0.003
2.62 ± 0.28
2.86 ± 0.32
19.8k
16
5.08 ± 0.03
1.82 ± 0.10
94.5 ± 2.5
0.89 ± 0.003
2.35 ± 0.005
2.59 ± 0.05
21.5k
Appendix
Table 8: VGAE performance on the test set for varying latent space dimensionalities.
Latent dim.
Sim. data footprint
Mem. reduction factor
4
92 MB
0.06
8
185 MB
0.12
16
369 MB
0.23
No compress.
795 MB
Appendix
Table 9: VGAE compression performance on the test set for varying latent space dimensionalities. “Sim. data” refers to the combined storage of the simulation mesh description and the corresponding sequence of temperature fields.
Figure 15: Temporal MAE of the VGAE on the test set for different latent dimensionalities. The initial peak in error is attributable to the concentration of reconstruction errors in the vicinity of the laser beam combined with the small domain size at early time steps, as discussed in Appendix G.1 .
Figure 16: Comparison of ground-truth temperature fields with predictions from the LM-RGNN and the Decoupled-RGNN for one of the test geometries at t=700 s. The corresponding temperature MAE is reported for each model. For visualization, the MAE color scale is clipped at 100°C, as the Decoupled-RGNN can produce substantially higher maximum errors compared to the LM-RGNN. The green lines indicate the part boundaries, enclosing the solid metallic region.
Figure 17: Comparison of ground-truth temperature fields with predictions from the LM-RGNN and the Decoupled-RGNN for one of the test geometries at t=1800 s. The corresponding temperature MAE is reported for each model. For visualization, the MAE color scale is clipped at 100°C, as the Decoupled-RGNN can produce substantially higher maximum errors compared to the LM-RGNN. The green lines indicate the part boundaries, enclosing the solid metallic region.
Machine Learning surrogates for Computational Fluid Dynamics (CFD), particularly Graph Neural Networks (GNNs) and Transformers, have become a new important approach for accelerating physics simulations. However, we identify a critical bottleneck in the field: while architectures have advanced significantly, the common underlying training paradigms remain bound to naive assumptions, such as node-wise supervision and explicit Euler time-stepping. These legacy choices ignore the stiff dynamics and local flux continuity inherent to numerous partial differential equations resolution methods, such as Finite Element, Difference, or Volume (FEM). In this work, we propose a unified framework to bridge the gap between geometric deep learning and rigorous numerical analysis. We introduce three key innovations: (1) Multi Node Prediction, a stencil-level objective that predicts field values for a node's full local topology, enforcing spatial derivative consistency; (2) Temporal Correction, replacing unstable explicit schemes with a predictor-corrector via temporal Cross-Attention; and (3) Geometric Inductive Biases, leveraging 3D Rotary Positional Embeddings (RoPE) to robustly capture rotational symmetries in unstructured meshes. We evaluate this framework across three architectures (MeshGraphNet, Transolver, and a Transformer) on diverse physics datasets. Our approach yields consistent improvements in accuracy and stability, particularly in long-horizon rollouts, while producing latent representations that generalize to unseen subtasks such as Wall Shear Stress or Pressure prediction. Code is available at https://github.com/DonsetPG/graph-physics.
In this work, we present COGENT, a continuous graph emulator with Neural Ordinary Differential Equations for long-term physical forecasting on irregular geospatial meshes. COGENT encodes a finite history of system states and associated forcing fields and external forcings with a graph-based history encoder, producing node-wise context vectors that capture both local spatial interactions and temporal evolution. These context vectors initialize and condition a latent Neural Ordinary Differential Equation whose dynamics are driven by interpolated future forcings and explicit relative rollout time. By modeling the forecast trajectory as a continuous latent dynamical system, COGENT can generate predictions at arbitrary future times rather than being restricted to a fixed temporal discretization. A residual decoder maps the resulting latent trajectories back to future physical states, enabling direct multi-step forecasting without repeatedly feeding predicted states back into the model. This formulation combines graph-based spatial representation, history-conditioned latent dynamics, and continuous-time rollout in a unified framework for mesh-based physical simulation emulation. In order to stabilize training with long-horizon supervision, we also propose effective rollout-horizon sampling and a progressive rollout-horizon scheduling strategy. We evaluate COGENT on transient ice-sheet simulations generated by the Ice-sheet and Sea-level System Model, demonstrating improved long-range stability over autoregressive graph baselines. These results suggest that continuous graph Neural ODEs provide a promising methodology for scalable physical forecasting on irregular geospatial meshes, particularly in applications that require stable long-horizon predictions and the ability to query system states at arbitrary times.
Accurate long-range prediction of geophysical systems is difficult due to strongly nonlinear dynamics, the high computational cost of full-physics simulations, and the error accumulation that arise when one-step autoregressive surrogates are rolled out over decades. Deep neural network can serve as efficient emulators, but most are trained only for next-step prediction and often drift or become unstable as the forecast horizon grows. We propose a multi-horizon graph neural network emulator that learns state-to-state transitions from a single current time to multiple future lead times within one unified model. The physical domain is represented as a graph, where nodes correspond to spatial locations with time-varying geophysical attributes and edges encode local spatial interactions. Given the current graph state, the model predicts the future evolution of key fields, ice thickness and ice velocities at all nodes, using a shared graph backbone with separate output branches for each target variable. To improve stability, the network predicts state increments relative to the current state, which are then added back to reconstruct future states. Training jointly optimizes all lead times with a unified regression objective, and inference uses a coarse-to-fine rollout that advances with larger jumps and selectively refines with shorter jumps to reduce drift and avoid redundant computation. Experiments on multi-decadal Pine Island Glacier simulations show that our approach achieves higher long-range accuracy and improved stability than both (i) an initial-state baseline that predicts each future time directly from the starting state and (ii) a standard single-step autoregressive rollout, producing a more reliable emulator for downstream climate and sea-level studies.
Zesheng Liu, Maryam Rahnemoonfar
Department of Computer Science and Engineering, Lehigh University, Bethlehem PA 18015, USA · Department of Civil and Environmental Engineering, Lehigh University, Bethlehem2026 PA 18015, USA