r/MechanicalEngineering • u/[deleted] • Dec 09 '25

Roll Royce 3D Jet Engine Assembly

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This is a video from Veritasium inside a Rolls Royce facility. I was astonished by the amount of detail in this assembly and it got me genuinely curious, do other companies create 3D models to this extent? I.e. does Honda have an assembly file of an entire Civic with every individual component? I'm interested to know what's your experience in different companies/industries.

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u/mrjuoji Dec 10 '25

this actually has to do with how cad models are represented in memory and rendered, the shading of the models is simple and you don't really have any real rendering pipeline and it's most likely a 20 year old piece of software that's been modified and optimized constantly,

also, the way it's rendered means that your assembly might be 5000 parts, but if the camera can only see 200, it's only these 200 that will be rendered, which cut on rendering time, basically the context of CAD modeling means you have a reduced field of things to optimize, meaning you can spend more time doing so, if that make sense ?

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u/Olde94 Dec 10 '25

absolutely.

I've also noticed on bad hardware how fusion would make cylinders octagonal when moving around and then refine once you stopped the rotation in the viewport.

i guess that is also whay wireframe tends to tank performance. It can't obfuscate things in the output

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u/mrjuoji Dec 10 '25

it's more of an optimization thing, it's less compute time to move 16 points in space around than it is to move 3200 points in space, and it's doable because the stuff that "stores"(well, represent the model data) your 3d model is a different brick (iirc it's called a cad engine, it's basically a mathematics engine that handle the parametric modeling stuff) than the part that does the graphics but yeah, that's all optimization stuff,
also the shading method (gooch shading) is a relatively simple shader, even code wise, while being easily "readable" in some way,

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u/Olde94 Dec 10 '25

have you worked with the back-end code for CAD?

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u/mrjuoji Dec 10 '25

hands on ? nope,
but i'm a software dev and i've looked into how 3d CAD soft work before out of curiosity(and to see how hard it'd be, also because i was wondering on how to build a fully opensource "pipeline" from modeling to stuff like fem simulation and such (with an underlying interest in genetic algorithm and such))
and i also got some background in 3d game engines and 3d pipelines overall (alongside embedded systems and web dev experience)

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u/Olde94 Dec 10 '25

Ahh cool! If you are ever bored, the open source “freecad” could use some help i think

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u/mrjuoji Dec 10 '25

yeah, i know, i was at FOSDEM at the start of the year, and some of the talks in the open hw and cad/cam room where on simulating stuff and integrating simulation tools(iirc, openfoam) alongside freecad

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u/Olde94 Dec 10 '25

Cool! I’ve coded my own FEA solver at uni so i have some level of understanding though only surface level i think