Hempel, PaulGupta, AryamanSbalzarini, Ivo F.Gumhold, StefanReina, GuidoRizzi, SilvioGueunet, Charles2025-05-262025-05-262025978-3-03868-274-51727-348Xhttps://doi.org/10.2312/pgv.20251151https://diglib.eg.org/handle/10.2312/pgv20251151The IceT library is widely used for parallel compositing but does not support non-convex volume domain decompositions. We provide a backward-compatible extension of IceT to handle non-convex domain decompositions of volume data. These are frequently produced in numerical simulations, but it is challenging to render them in parallel due to the non-commutativity of alpha compositing. We enable parallel volume rendering of non-convex domains in IceT by extending its parallel compositing to layered images. Our code follows an embedded design, extending and generalizing IceT's internal functions for image compression, splitting, compositing, and decompression to efficiently handle layered images, while maintaining the existing functionality and API. We perform scalability tests and provide our implementation open-source in a public repository, with in-line documentation and integration tests.Attribution 4.0 International LicenseCCS Concepts: Computing methodologies → Distributed algorithms; Rendering; Human-centered computing → Visualization techniquesComputing methodologies → Distributed algorithmsRenderingHuman centered computing → Visualization techniques10.2312/pgv.202511515 pages