F3D vs Kompakkt

F3D is free software for viewing 3D data, browsing models, and generating renderings. It supports lighting and materials for realistic rendering, animations with GPU-accelerated skinning for character rigs, and visualization tasks such as CAD, Gaussian splatting, volume rendering, and scientific work. Its supported formats include VTK, STL, DICOM, STEP, OBJ, glTF, FBX, USD, IFC, and Gaussian splat files, among many others. Packages are available for Windows, macOS, Linux, and Android, and a browser viewer can open or accept dropped files and provides rendering and display controls. Developers can use a Python package, a beta JavaScript/WebAssembly package, or the libf3d C++ library with Python and Java bindings. F3D is distributed under the BSD 3-Clause License. Some capabilities have specific limits: FBX PBR materials and Alembic materials are unsupported, while Gaussian splatting requires OpenGL 4.3, which macOS does not support. Documentation also says volume rendering and HDRI need a decent GPU. Plugins can vary by package.

Kompakkt has no write-up on Specifiction yet; its figures are above.