Webots is an open-source robot simulator providing a complete environment for modeling, programming, and simulating robots. It consists of a C++ Qt-based main application (src/webots) that manages 3D rendering via the custom WREN engine (src/wren), physics simulation via a forked ODE engine (src/ode) with fluid dynamics extensions, and a multi-language controller API (C, C++, Python, Java, MATLAB) in src/controller. The repository includes a vast library of reusable robot models, sensors, actuators, objects, vehicles, and environments under projects/, as well as extensive documentation (docs/) and a web-based streaming interface (resources/web/wwi). The architecture is modular: the simulation world is defined in VRML-based .wbt files, robots are instantiated from PROTO definitions, and controllers run as separate processes communicating via shared memory. Webots supports ROS integration, SUMO traffic simulation, and OpenStreetMap import. The project is actively maintained with comprehensive CI/CD, test suites, and packaging scripts.
This repository provides a high-performance surface reconstruction system for SPH (Smoothed Particle Hydrodynamics) fluid simulation data. The core library, splashsurf_lib, implements a marching cubes pipeline that converts particle positions and densities into triangle meshes, with subdomain-based parallel decomposition, SIMD-accelerated kernel evaluation (AVX2, NEON), and optional post-processing (weighted Laplacian smoothing, barnacle decimation, quad conversion, attribute interpolation). The system is exposed as a CLI tool (splashsurf), a Python package (pysplashsurf via PyO3), and a Blender add-on (splashsurf_studio) for interactive viewport and render-time reconstruction. The architecture is modular: a generic library with traits for numeric types, a dense subdomain grid for parallelism, a half-edge mesh for decimation, and a custom nom-based BGEO parser. The codebase is well-structured with strong emphasis on performance and reproducibility, and it implements the research from Löschner et al. (2023) on weighted Laplacian smoothing. It targets researchers and artists working with SPH simulations (e.g., SPlisHSPlasH) and supports multiple input/output formats (VTK, PLY, OBJ, BGEO, XYZ, JSON).
PhiFlow is a Python library for differentiable physics simulation, primarily targeting fluid dynamics, particle systems, and PDE-based optimization. It provides a unified field abstraction (CenteredGrid, StaggeredGrid, PointCloud, Mesh) with automatic resampling and boundary handling, enabling seamless integration with machine learning workflows. The library supports multiple backends (NumPy, PyTorch, TensorFlow, JAX) and features a rich geometry module, physics solvers (advection, diffusion, incompressible flow, SPH, waves), and visualization tools. While its core abstractions are clean and well-tested, the codebase exhibits some technical drift due to deprecated API surface, large monolithic Dash-based web UI, and heavy reliance on the external phiml tensor library. Nonetheless, it is actively maintained with extensive test coverage and a growing research community.
HPWater is a water rendering system for Unity HDRP that implements advanced graphical techniques including ray-traced refraction, volumetric lighting, interactive caustics, and fluid dynamics simulation. The architecture follows Unity's Render Graph API with modular components for different water effects. Key entry points include the main HPWater.shader orchestrator and various C# integration files that hook into HDRP's rendering pipeline. The system processes water rendering through multiple passes: GBuffer encoding for water-specific data, caustic simulation via compute shaders, volumetric light scattering with temporal filtering, refraction calculations, and fluid dynamics for wave propagation. While the core implementation is tightly coupled to Unity's HDRP, it demonstrates solid graphics programming practices.