I build machine learning systems that facilitate billions of user interactions at global scale.
My work spans computer vision, generative modelling, and 3D understanding, with products deployed to hundreds of millions of users.
Currently
Snap Inc.Senior ML Engineer
Impact
2B+ monthly viewsacross my AR products
Expertise
Gen AI · 3D MLon-device, real-time
Education
Imperial College LondonPhD, Machine Learning
§ 01
Career
2020 – present
Senior Machine Learning Engineer
Snap Inc. · London
Owner and lead developer of two core AR products: generative Body Avatars and 3D hand tracking.
Video generation and model distillation (2024 – present). Developed Body Avatars, real-time on-device transformations of users into digital characters, by training and distilling pose-controlled human video diffusion models. Launched publicly in Lens Studio and EasyLens (Snap's AR creation platforms); individual effects reached over 300M views.
3D hand tracking (2020 – 2025). Built the hand tracking system that became a core component of AR effects, used by hundreds of millions of people and generating over 2B monthly views.
End-to-end ownership. Own the full stack: architecture design, training strategies, evaluation, large-scale data collection and synthetic data generation, on-device optimisation, and production deployment.
Impact-driven research. Evaluate models on engagement and product metrics, in addition to technical metrics, and use those signals to prioritise the research roadmap.
2019 – 2020
Computer Vision Scientist
Ariel AI · London Acquired by Snap Inc.
Early employee; joined during my PhD to bring research into production.
Developed a real-time, on-device system for 3D hand mesh reconstruction from images.
Built a 3D statistical model of human hands trained on 500k hand scans from 1,300+ individuals.
Responsible for large-scale data collection and processing using a 3D motion capture setup.
Developed a new category of augmented reality products that transform users into digital characters with pixel-level accuracy. The effects operate in real time on mobile devices; anyone can create their own character from a single reference image.
Character consistency. Trained pose-controlled video models (Wan, Stable Diffusion) and image-editing LoRAs (Qwen-Image-Edit) so a character in a reference image stays consistent across poses.
Distillation. Distilled video models into real-time on-device networks.
Paired data generation. Built a pipeline that uses the pose-controlled model to produce image-aligned character annotations.
Platform integration. Integrated the technology into Lens Studio and EasyLens (AR creation tools), enabling creators to train their own AR transformations.
Agentic pipeline. Built an agentic concept design system that drives data generation, training, and publishing. It has produced thousands of effects, published to users and available to creators for remixing.
Impact. The top five characters passed 1B views within a month of launch. Nearly 2k creators produced tens of thousands of AR effects.
2024 – 2025
Controllable Human Video Generation
Snap Inc.
Worked on pose-controlled human video diffusion, from improving gesture fidelity to 360° generation, 3D reconstruction, and digital character animation.
Human video diffusion. Trained pose-controlled human video diffusion models, initially to improve hand and gesture fidelity. Identified an opportunity for digital character transformations that became the basis for Body Avatars.
360° generation and 3D Gaussian Splatting. Rendered a 360° human dataset, trained a video model to generate multi-view sequences from a single image, and reconstructed 3D humans with Gaussian Splatting from the generated views.
Developed a hand tracking system used by hundreds of millions of Snapchatters. Owned end-to-end product development, including model design and training, on-device optimisation, data collection, and production deployment.
Modelling and training. Designed, built, and trained a 3D hand mesh reconstruction system.
On-device optimisation. Developed low-end, mid-end, and high-end variants for different devices and use cases.
Data collection. Ran data collection efforts to address failure cases. Created the semi-synthetic dataset for dense pixel-accurate supervision and differentiable rendering losses. Experimented with training a ControlNet-based data generator.
Auxiliary models. Developed hand segmentation, surface normal, and depth estimation models.
Impact. The system became a core component of augmented reality effects and enabled novel brand experiences for major companies such as Disney, Cartier, Dior, Lego, Netflix, Samsung, Coca-Cola, McDonald's, KFC, and many others.
2019 – 2024
Hand Shape Modelling
Ariel AI · Snap Inc.
Built a 3D statistical model of human hands and a registration system that brings hand scans into correspondence.
Data collection. Ran large-scale 4D data collection, obtaining 500k scans from over 1,300 participants aged 3–81, with high-resolution meshes and textures.
Registration. Built a pipeline for iterative optimisation that fits a 3D hand model to noisy, incomplete scans.
Statistical deformable model. Trained a 3D hand shape model with independent bone-length and shape variations.
Synthetic dataset. Trained a texture model and built a semi-synthetic dataset with normal, depth, segmentation, and UV annotations.
§ 03
Publications & patents
2020
Weakly-Supervised Mesh-Convolutional Hand Reconstruction in the Wild
D. Kulon, R. A. Güler, I. Kokkinos, M. Bronstein, S. Zafeiriou · CVPR 2020 · Best Paper nominee
2019
Single Image 3D Hand Reconstruction with Mesh Convolutions
D. Kulon, H. Wang, R. A. Güler, M. Bronstein, S. Zafeiriou · BMVC 2019
2021
Advancing 3D Hand Reconstruction and Modelling with Geometric Deep Learning
D. Kulon· PhD thesis, Imperial College London
2023
Hand Surface Normal Estimation
R. A. Güler, D. Kulon, H. Tam, H. Wang · US patent
2023
Depth Estimation from RGB Images
R. A. Güler, D. Kulon, H. Tam, H. Wang · US patent
2020
Generating Three-Dimensional Object Models from Two-Dimensional Images
D. Kulon, R. A. Güler, I. Kokkinos, S. Zafeiriou · US patent
§ 04
Education
2018 – 2021
PhD, Machine Learning
Imperial College London EPSRC scholarship
Advised by Prof. Stefanos Zafeiriou and Prof. Michael Bronstein.
Thesis: Advancing 3D Hand Reconstruction and Modelling with Geometric Deep Learning.