Alejandro Amat Payá

I'm a 24-year-old Electrical and Computer Science Engineer currently working as a Research Associate at Carnegie Mellon University. I am also attending classes in the Master's program in Computer Science at CMU.

My research focuses on real-time differentiable rendering, 3D Gaussian Splatting, and computer vision, with deep specialization in high-performance computing and advanced graphics programming. I specialize in translating cutting-edge computer vision, machine learning, and graphics research into real-time functioning systems. I leverage CUDA optimization, Vulkan/OpenGL development, and advanced system architecture to push the boundaries of real-time rendering and neural scene reconstruction.

I have 3+ years of experience building production-ready systems that combine computer vision, 3D graphics, machine learning, and differentiable rendering. I'm passionate about bridging the gap between theoretical research and practical real-time applications, creating systems that make advanced graphics and ML techniques accessible for real-world deployment.

Alejandro Amat Payá
Electrical & Computer Science Engineer

Email: alejandroamatp@gmail.com
Academic: aamat@andrew.cmu.edu
Location: Pittsburgh, PA
Phone: +1 412 512 9640

Research Interests

Real-time Rendering
3D Gaussian Splatting
CUDA/GPU Computing
Differentiable Rendering
HPC Computing
ML/Computer Vision

Professional Experience

Research Associate
Carnegie Mellon University, Pittsburgh, PA
February 2024 – Present

Conducting research at the intersection of machine learning, computer graphics, and high-performance computing, specializing in real-time systems and optimization for 3D computer vision applications. Working in lab focused on realistic 3D reconstruction. Responsible for developing and optimizing cutting-edge rendering pipelines, GPU acceleration systems, and neural scene reconstruction algorithms.

  • Contributed to static rendering component for accepted SIGGRAPH 2025 journal paper on 3D live streaming using Gaussian Splatting, achieving 3-4× speedup through load balancing kernels and CUDA graph pipelines with 15ms/iteration for 1.5M Gaussians
  • Built high-performance computer vision systems with PyTorch prototyping and translation to real-time ML/graphics applications using advanced C++ optimizations including SIMD vectorization, OpenMP parallelization, Eigen library for fast matrix operations achieving 2-6ms/frame performance with cross-platform deployment using CMake and Python bindings
  • Developed differentiable rendering pipeline using Slang/gfx API with custom GPU Adam optimizer and CUDA complete optimizations featuring automatic differentiation from fragment shaders, delivering 116× speedup over NVIDIA Falcor and 4× speedup in 2D Gaussian Splatting with profiling using Nsight Systems, Nsight Compute, and RenderDoc
  • Train MLP architectures with PyTorch prototyping and TensorRT deployment, and develop custom differentiable optimizations with second-order nonlinear optimization algorithms across distributed systems
  • Supervise visiting researchers and interns in 3D Gaussian Splatting and computer vision projects, conducting technical interviews and project coordination
AI Researcher
I2cat Foundation, Barcelona, Spain
May 2023 – December 2023
  • Pioneered real-time 3D imaging algorithms with MIMO FMCW mmWave radar for reflective surface optimization
  • Published 2 papers on location-based utilization of reconfigurable intelligent surfaces for mmWave sensing
Unity VR Developer
IESE Business School, Barcelona, Spain
October 2023 – April 2024
  • Developed cross-platform VR application for IESE/MIT/LBS collaboration
  • Deployed to Android, iOS, and Web/Desktop using Unity and Google Cardboard SDK
  • Implemented Firebase integration for real-time data synchronization
Student Research Lead
HP, Barcelona, Spain
February 2023 – July 2023
  • Led university team on collaborative project with HP, developing Python package using Intel RealSense cameras
  • Implemented DBSCAN and RANSAC algorithms for pointcloud segmentation and wall plane detection
Big Data Engineer Intern
Mango, Barcelona, Spain
May 2022 – September 2022
  • Built data pipelines using Jenkins CI/CD, Airflow, MySQL, AWS, Python & Docker for retail analytics
  • Developed automated data processing workflows for large-scale retail data analysis
  • Implemented monitoring and logging systems for production data pipelines

Publications

Junkai Huang*, Saswat Subhajyoti Mallick*, Alejandro Amat, Marc Ruiz Olle, Albert Mosella-Montoro, Bernhard Kerbl, Francisco Vicente Carrasco, Fernando de la Torre.
"Echoes of the Coliseum: Towards 3D Live Streaming of Sports Events."
ACM Transactions on Graphics (SIGGRAPH 2025)
Filip Lemic, Jalal Jalali, Gerard Calvo Bartra, Alejandro Amat, Jakob Struye, Jeroen Famaey, Xavier Costa Perez.
"Location-based real-time utilization of reconfigurable intelligent surfaces for mmWave integrated communication and sensing in full-immersive multiuser Metaverse scenarios."
IET Advanced Metaverse Wireless Communication Systems, pp. 101-136, 2025

Selected Projects

Vulkan 3D Gaussian Splatting Renderer

Cross-platform C++17 neural rendering engine breaking CUDA vendor lock-in for cross-platform neural scene rendering with Vulkan and GLSL compute shaders.

  • Built complete 3DGS implementation with tile-based rasterization and multi-stage radix sort (histogram computation, work-efficient prefix sum using up-sweep/down-sweep phases across ping-pong buffers)
  • Created ImGui keyframe animation system for real-time smooth sequence generation with interpolated camera movements, FOV control, culling, wireframe rendering and performance monitoring
  • Achieved stable 60 fps on Nvidia 3060 Ti and 24-45 fps on Apple Silicon (MoltenVk translation) on 2M Gaussian pointcloud with bilinear upsampling for Retina display support
Vulkan
C++17
GLSL Compute
Neural Rendering
Cross-platform
Real-time Systems
Differentiable Rendering with Slang

Built real-time differentiable rendering pipelines from scratch using Slang shader language, C++, and gfx API for inverse rendering applications.

  • Developed inverse texturing system achieving 116× speedup over NVIDIA Falcor through automatic differentiation and optimized shader compilation
  • Implemented 2D Gaussian Splatting optimization with 4× performance boost enabling real-time parameter optimization and scene reconstruction
  • Created complete automatic differentiation framework with gradient computation for lighting, materials, and geometry parameters
Slang
Differentiable Rendering
Automatic Differentiation
Real-time Systems
Inverse Rendering
High-Performance CUDA Optimization Suite

Collection of GPU-accelerated algorithms with massive performance improvements through advanced CUDA optimization techniques.

  • Sobel Edge Detection: 224,733× speedup over NumPy achieving 10.8 billion pixels/second throughput via shared memory tiling, warp optimization, and branch divergence elimination
  • 3×3 SVD Implementation: 120× speedup vs PyTorch for computer graphics applications with custom CUDA kernels and Python bindings
  • Fused MS-SSIM: Optimized Multi-Scale Structural Similarity Index implementation with PyTorch integration for real-time image quality assessment
CUDA
PyTorch
GPU Optimization
Python Bindings
Linear Algebra
VR Educational Platform for IESE/MIT/LBS

Cross-platform VR application developed for prestigious business school collaboration between IESE, MIT, and London Business School.

  • Built immersive educational experience using Unity and Google Cardboard SDK deployed across Android, iOS, and Web/Desktop platforms
  • Implemented Firebase real-time synchronization for multi-user collaborative sessions and progress tracking
  • Created intuitive VR interfaces optimized for educational content delivery and student engagement
Unity3D
VR Development
Cross-platform
Firebase
Educational Technology
Custom Rendering Engines

Multiple custom Vulkan/OpenGL implementations featuring 3D rendering systems with advanced lighting models, mesh rendering, shadow mapping, camera controls, and optimized shader pipelines.

Vulkan
OpenGL
HLSL/GLSL
3D Graphics
Operating System Kernel Implementation

Custom x86 operating system kernel built from scratch in C and assembly language for educational and research purposes.

  • Implemented complete process scheduling system with round-robin and priority-based algorithms, context switching, and multi-tasking support
  • Built memory management subsystem featuring virtual memory, paging, page fault handling, and kernel/user space separation
  • Developed system call interface, hardware interrupt handling, keyboard/timer drivers, and basic file system operations
C/Assembly
Operating Systems
Low-level Programming
System Design
Memory Management

Education

Master of Science in Computer Science
Carnegie Mellon University, Pittsburgh, PA
2024 – Present

Currently attending classes in the MSCS program at CMU.

Bachelor's Thesis Research
Carnegie Mellon University, Robotics Institute
February 2024 – July 2024

Thesis: "Real-Time Differentiable Rendering with Slang" - Built differentiable rendering pipelines achieving significant performance improvements. Supervised by Dr. Fernando de la Torre and Francisco Vicente at the Human Sensing Lab. Grade: 10/10

Dual Bachelor of Engineering
CFIS-UPC, Barcelona, Spain
2019 – 2024

Electrical Engineering & Computer Science
GPA: 8.43/10 (Rank: 6/237) & 8.1/10 (Top 5%)
Award: 6th best student of the 2024 class out of 240 students
10 Honours in subjects including Audio Processing, Mobile Communications, AI, and Computer Graphics