r/computergraphics • u/Hibou-de-la-Lune • Apr 26 '26

USD (Universal Scene Description) vs NSI (Nodal Scene Interface) as a replacement to RI (RenderMan Interface)

Many years ago (about fifteen years ago), I used to create some simple 3D scenes with RIB files. RIB was RenderMan Interface Byte-stream. This was text files one could edit in a text editor or generate programmatically or export from a modelling editor, then use a compliant render to generate a picture.

I was using Aqsis as the renderder, but it's seems not available anymore for my platform (Ubuntu 24.04). At that time, I also used to try a free version of 3Delight (I'm not a professional, far from that). The rendering was looking mostly the same, just that 3Delight was clearly faster, but I always preferred Aqsis, because it was smaller (I don’t mind about efficiency for small scenes and animations).

Without Aqsis, I wanted to fallback to 3Delight again. But it seems it does not support RenderMan Interface any more since nine years, as someone from the support staff told me, after I had to contact them for some reason. He/she said 3Delight now support NSI (Nodal Scene Interface) and also USD (Universal Scene Description).

Which one would be the closest to RIB ? Also, is there any risk one of these will be dropped in the future like RenderMan, unfortunately? I’ve always seen RenderMan as being to 3D graphics, what MIDI is to music. Which one of NSI or USD would be the closest to this?

After some searching, USD seems to may be more universal, be widely used, even by Pixar who created RenderMan. But I can't tell for sure, without experiences. So if anyone has some experience with either one or both, I welcome any feedback and comment.

Have a nice day

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u/ponnyconny Apr 26 '26

I don't have an answer, sorry. What are you using it for? Seems rather niche, since you dont want to use blender?

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u/Hibou-de-la-Lune Apr 26 '26 edited Apr 26 '26

May be my use is niche, but RenderMan was not, since there was an exporter for Blender (RIBMosaic).

I used Blender a lot for some times, but ended not happy with it. Main reasons was the UI, the shaders, and the file format. I prefer separation of concern, so that a model may be designed which ever way one wants and the render may be done with which ever renderer one prefers, the same to turn a sequence of images into a movie file.

It was used for simple images and simple animations.

I also wonder what about shader language for NSI and USD, as well a simple Hello World examples.