If I recall Nurb file was originally developed by 3D Max in the Artist CAD industry, but later adopted into an universal standard called IGES for the Engineering CAD industry.. Whereas Artistic CAD industry couldn’t agree on a universal standard between Maya and other smaller bespoke artistic software (used in the film industry) in the late 90s so they starting to adopt IGES in the early 2000 before a takeover by Autodesk who already own 3D max.
Same can be said with Engineering CAD such as Solidworks and ProE (now creo) is actually written / originated one of the same, before branching out into 2 separate companies. Many base features remain this including file structure.
Since early 2000 many Pro 3D CAD users from both sectors (Artist & Engineer) saw the divergence of Pro 3D CAD packages and there was a growing demand for a universal file standard for cross party communications. i.e… When a Pro designer uses one package e.g. Solidworks / Unigraphics and require to be manufactured (sub-contracted) by another company for injection moulding for example they most likely uses other CAD packages e.g. Catia / ProE (superior at mould tool manipulation),
In short, the universal communication standard (for Engineering secto) has already happen / setup since the early 2000 using STEP (less so with IGES), because before 2000 most still uses AutoCAD (2D) or worst pen and paper.
What IGES specialises at (as part of Nurb structure) is to retain freeform surface geometry & 3d sketch & splines from the original CAD you have created. This means 2 things: It allow for open ended or missing surfaces during translation whereas STEP is a closed loop, because STEP is a true solid by default whereas IGES (or nurb) isn’t as it only retain surface information and not interior. So what happen with Nurb type file is that when you import file like IGES back into CAD is that they try to stitch all the exterior information back up to make it into a solid cad object again.
This can only be done in Engineer CAD and not Artist CAD with Nurb files. it two very different thing, in fact it 2 different CAD category, because by default ALL Artistic CAD software are written as surface only (no solid information inside as there is no need for creative or even 3d printing industry), whereas Engineering CAD are more complex where by default it create solid information (not hollow inside) but it can also import surface only information as well. This is why Engineer CAD have many ways to measure & dimension an object e.g. centre of mass, density of object (useful for 3d print with supports) parabolic arc generated by specified mathematical curvature e.g. aerofoil design. Whereas Creative / artistic CAD will always be created by approximation, which is fine because I cannot see any reason why Creative CAD should adopt solid creation considering it hold more unnecessary on screen information compared to STEP, parasolid & other Engineer CAD file.
But this so called unnecessary on screen information, is actually very useful for turning digital information into physical object (whether if it injection moulder, sheet metal maker, investment caster, CNC machinist & etc ), this is why manufacturer uses STEP as a standard (for 3D) for imports and not OBJ or STL. In fact, speak to any Professional Model makers (who may own upto 20 different 3d priners from Pro to Enthusiast machines) and majority would recommends STEP not OBJ or STL, because it allow them to easily manipulate a true solid object in CAD compared to “surface only” (stitched) before printing.
I know all this because I’ve been using 3D CAD and 3D printers professionally & continually since early 2000s and I’ve used both CAD discipline (Creative & Engineer, 2 each) this including numerous 3D printing machines and research into possible applications into the real world for various companies .e.g Rapid Tooling, Jig & Fixture, traditional model making for clients & etc that just within the 3D printing worlds (a.k.a. additive manufacturing).
My main responsibility is to ensure the digital design is good enough to be mass produced and I failed to see any benefit of using CAD packages . from the artistic sector such as MOI, Blender & etc. especially when this MOI is a strip down version from Pro software like 3D max / Maya. I can see you are quite familiar with Nurb type 144 and even 126 in which IGES is excel at of extracting vector / points information, but STEP file by nature is more stable and less error.
The point is every time you convert a file (i.e. importing or exporting) from native from your CAD, original details are lost, this is especially true with STL as it is converted into vector based (just open a STL ASCII based file in note and you will know what I mean).
It like saving RAW (native CAD) into JPG (STL), whereas lossless file (almost) conversion like RAW (native) > Compressed RAW with Zip / RAR (STEP, Parasolid, IGES)
For Engineer CAD, what you see on screen isn’t what you get as you can get much more detail, which unlike Artist CAD. In fact, I would argue a 20mb native model (converted from STEP) is far better for most PC to handle this workload than a 200mb STL. and has very little with the GPU spec.
It true that since 2006~2012 I’ve noticed a further divergence of open source 3D packages derived from Art CAD sector (vector / surface based) and less so from engineering CAD, because it easier to code surrounding STL.
It true that STEP isn’t as straight forward as STL when writing the software, but STEP is actually open source and definitely not propriety properties to any company.
I didn’t buy the Form2 machine just creating pretty looking models (this isn’t the only applications), but retain some of the function for assembly for example. Because of this 200mb limit, I on occasion had to compromise with the decision of whether to reduce the polygon counts to visible sees rawness of the prints OR reduce function of the models, gears threads, piston, o-ring, body within body (not with Form2). This is to ensure everything fits and sometimes assembled with bespoke metallic components, without too much hassle of post-modding the prints or the CAD models as we don’t have all day for that if compared to the Enthusiast communities. STEP would alleviate that when time is of the essence.
Beside using OBJ & STL, Even Makerbot (another Enthusiast based machines) already adopted STEP so why don’t Fromlabs? As it would open up CAD users from the Engineering side as well, such as supports manipulations (beside the Creative / Artistic CAD users). Or even using CAD library like GrabCAD and 3D Concept Central (most models in here don’t use STL for the reasons stated above).