Khronos’ glTF is the first 3D model format to specify physically-based rendering (PBR), meaning it contains material properties that define in real-world units how light should be reflected & refracted in terms of physics. This means renderers are free to innovate in GPU shaders to create more and more accurate approximations of the underlying physics, because glTF does not specify any single approximation. This also means that while different renderers may make different tradeoffs of accuracy vs. speed you can have confidence that your glTF will look consistent (though not pixel-identical) even across unrelated codebases. We call glTF the JPEG of 3D because it is compressed for efficient web delivery and can be rendered consistently by a large number viewers.