Mohamed Elrefaie
Physics of Fluids 2025

TripOptimizer: Generative 3D Shape Optimization and Drag Prediction using Triplane VAE Networks

Parsa Vatani, Mohamed Elrefaie, Farhad Nazarpour, Faez Ahmed

Massachusetts Institute of Technology

Fully differentiable
From geometry to drag
Triplane VAE
Compact 3D latent space
Industry geometry
Industry-standard car designs
The method

Optimize the shape by descending through the surrogate

TripOptimizer is a fully differentiable deep-learning framework for rapid aerodynamic analysis and shape optimization. A triplane variational autoencoder compresses 3D car geometry into a structured latent space; a drag-prediction head evaluates aerodynamics directly from that latent. Because the whole pipeline is differentiable, drag gradients flow back into the latent space — turning shape optimization into gradient descent.

Generative shape optimization: geometry evolves along the drag gradient in the triplane latent space.
Generative shape optimization: geometry evolves along the drag gradient in the triplane latent space.
Contributions

What the paper delivers

Triplane geometry encoding

Three axis-aligned feature planes represent full 3D car shapes compactly, capturing fine geometric detail without volumetric memory costs.

Drag prediction from latents

Aerodynamic performance is predicted directly in latent space — no meshing, no simulation in the loop.

Gradient-based 3D design

End-to-end differentiability enables generative optimization of industry-standard designs, producing lower-drag variants in minutes rather than CFD-weeks.

Reference

Citation

@article{vatani2025tripoptimizer, title = {TripOptimizer: Generative Three-Dimensional Shape Optimization and Drag Prediction using Triplane VAE Networks}, author = {Vatani, Parsa and Elrefaie, Mohamed and Nazarpour, Farhad and Ahmed, Faez}, journal = {Physics of Fluids}, volume = {37}, number = {12}, pages = {127113}, year = {2025} }
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