The NVIDIA-Omniverse/PhysX repository is a comprehensive physics simulation ecosystem comprising the PhysX SDK (rigid body dynamics, articulations, vehicle physics), Blast (destruction/fracture), Flow (fluid/fire simulation), and ovphysx (Omniverse integration layer with USD support and Python bindings). It provides real-time physics computation for games, VR, robotics, and virtual production workflows. The architecture features modular SDKs with C/C++ core APIs, C wrappers, and Python bindings, extensible via plugin systems (e.g., OmniPhysX for USD). Key entry points include PhysX scene creation functions, ovphysx tensor binding APIs, Blast authoring tools, and Flow context initialization. Data flows involve defining physics assets, stepping simulations, and extracting results (poses, forces, contacts) or tensor views for ML interop via DLPack. External dependencies include USD, CUDA, Vulkan, Premake, and packman for dependency management. The codebase demonstrates strong engineering practices with RAII patterns, custom allocators, handle-based resource management, and platform abstraction layers.
FLIP Fluids is a production-grade Blender addon for liquid simulation, integrating a custom C++ FLIP (Fluid Implicit Particle) engine with a comprehensive Python UI. The engine implements advanced numerical methods including level sets, variational pressure solvers, PCG with MIC(0) preconditioning, force fields, whitewater particles, and viscosity solvers, all backed by a vendored Eigen linear algebra library. The Blender addon provides property groups, UI panels, preset management, material libraries, and command-line scripts for baking, rendering, and Alembic/USD export. The architecture is a hybrid: the C++ engine is compiled as a shared library and accessed via C bindings and Python ctypes wrappers, while the addon code follows standard Blender patterns (operators, panels, property groups). Key entry points include the baking operators, simulation domain properties, and the engine's Python bindings in `ffengine/`. External dependencies include Blender (4.5+), Eigen, and optionally Mixbox for color blending. The codebase is well-structured with extensive version compatibility layers, but the vendored Eigen and reliance on Blender's evolving API introduce moderate technical drift.
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).