Throwing another “why does Rhino have issues filleting simple surfaces” on the stack:
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I would recommend to rename it to:
Why do i get all the SolidWorks files to add fillets in Rhino because they cannot continue with all these red exclamation marks…
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Yeah, it’s 2023 by now… still requesting an _AutomagicalFillet4idiot command for the sake of time savings alone. I’m considering a EUR156,500.- a month SW license for just the filleting cuz dem clients just cant get enough of those quick smooth automatic fillets.
Properly filleting polysurfaces in Rhino gets its own subsection on the invoices I send. Client raises an eyebrow and asks “how and why is this still a thing?”…
Love the software though, happy customer overall, you guys are doing a great job, much obliged
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Open Broadcaster Software | OBS (obsproject.com) is great for recording your screen…
What the presenter said about ‘parallel vs perspective’ projection effecting the position of geometry is nonsense.
I’m willing to bet it’s not true. The presenter also said something about the ‘black’ color of the part effecting the way SW can interpret the features, which is also nonsense, but I’m willing to assume the presenter merely misused vocabulary there.
And, the video was mostly about transferring geometry between Rhino and SW via .iges/.step formats.
The filleting differences and issues that plague both Rhino and SW as you implied, is yet to be settled – imo. But, I’m still digesting this thread so we’ll see.
Keep in mind you’re commenting on the state of Rhino and SW from 2017.
There has been a lot of development work between then and now.
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If they wanted to. 
I agree. I don’t see the “advantage” at all. Meaning, I don’t agree that there’s any “advantage”.
Yes Rhino is very surgical in nature and you can create almost any free form geometry, but the point here is about “fillets” and Rhino’s deficiencies in that regard.
Rhino’s filleting deficiencies have been unsolved since antiquity.
I’ll be getting to the bottom of this.
This is getting reiterated many times, which I think is a good thing to reflect on, as I have a few insights on the matter relative to “joined surfaces” – “multi faced breps”… “edges being pulled away” etc.
Also later, I’ll reflect more on the trim problems I’ve seen with polysrf edges, and adjacent srf’s etc.
IKR 
need to add like 40% inflation fee now though haha.
I totally know what you mean. But, I’ll be addressing the polysrf version of problems here cause my opinion is more interested in the fillet edge versions, especially with variabilities of radii.
I prefer it that way, but definitely each method deserves needed attention, while I think the filletsrf version actually avoids alot of the problems that plague the filletedge version. This is partially because one version only has to deal with 2 single srf’s, whereas the other has to deal with many srfs and many adjacent edges to trim, etc.
It’s a little better but I know what you mean.
very true. I’m just being sensitive about the presenters comments on parallel and perspective projection cause of my experience with those features in different software. I just think the presenter butchered it a bit.
And I’d say Rhino has very wonderful ability to project perspective as apposed to other programs – some of which have no perspective projection at all, even when they claim they do, like ‘Alibre Design’ for example has very poor perspective projection. And Mastercam has none 
But, the projections certainly have nothing to do with misplacing object positions as the presenter explained. So, there again maybe a mix-up of terms, idk. Maybe some users work better in different projections than others and it’s really user error rather than software error – in terms of object placement.
Here again I’ll bring up the things like polysrf render-mesh, multi face brep, ‘edges pull away’, and yes the proverbial “Rhino can’t figure out how to remove adjacent srf’s” problem.
Here’s reiterated simple example:
(as fillet gets closer and closer to adjacent edge)
(Rhino then fails to know what to do next) – delete face and fillet…
Yes I somewhat agree, but I’m starting to have anew opinion, whereby Rhino merely shows more truth than most CAD’s.
I like to believe Rhino can become very much better parametrically than even “the best” CAD’s.
I’m probably willing to say Rhino is one of the top 3 or 5 CAD’s, but still has some growing to do.
I agree. The price and the sense of user to seat ownership, makes it the best of it’s kind.
I do remember one of the first important things I ever did with Rhino back in 2004-2007 was I used it to convert files from one CAD program format to another
But yes there’s still some fillet evolution to be had 
I agree, but I think it’s all relative to the ‘breps’ and how the surface edges are pulled away during joining of srf’s into polysrf’s, trimming, etc.
as this topic got revived…
please feel free to add your fillet failing examples here:
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A little tip. Fillet is trimmed surface, which means it could be “not” trimmed. Solidworks sometimes cheating on fillets. Rhino Import stp export from SW, you will find untrimmed fillet surface.
In Rhino, how far trimmed edges are from the underlying surface is supposed to be determined by the user specified absolute tolerance. In theory edges are never supposed to “pull away” from the faces to which they belong any farther than the tolerance.
If you use Rhino’s surface modeling tools on well consturcted surfaces, it is very rare to find edges that are out of tolerance.
In my experience, if you use Rhino’s solid modeling tools you can never be sure that edges will be within tolerance.
And yes, once you have trimmed surfaces with mutilated boundaries that are out of tolerance, it can make subsequent operations using those surfaces much more difficult.
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Tha’s basically how I’ve understood it since I first began noticing it and testing it.
I think that’s because the solids are deviations from original single faced breps transformed into their proverbial multifaced breps – hence pulled away from originals.
Indeed another good example demonstrating how Rhino doesn’t know how to deal with the adjacent edge and surface, etc. to trim and close.
Some ppl might say “well just merge those two surfaces first” haha. But I intend to provide examples where that’s not an option.
For now, I think the Rhino programmers should figure out why Rhino can’t magically trim adjacent edges properly and delete hangnail faces per say.
I disagree. Solids when made using Rhino’s surface modeling tools have accurate Boundary representation. Edges are within tolerance of the surfaces that they help define.
The models I make are solids which are eventually used for CNC machining, but they also need to be exported to other CAD programs for prior approvals. Almost all the applications I export to are solid modeling applications like Solidworks, ProE, Unigraphics, etc. . When I use Rhino’s surface modeling tools I have no problems in both exporting and creating solids. When I have used Rhino’s solid modeling tools I have had many problems both with downstream operations in Rhino and with exports to other Cad programs.
For instance, when I use Rhino’s Filletsrf command to create fillets those surfaces are recognized as fillets by other solid modeling applications, but when the same fillets are created using filletedge they are not recognized as fillets. Accuracy is definitely part of the problem, but beyond that, as a user, it is pointless to speculate.
My advice, if you want good solids use Rhino’s surface modeling tools and ignore the tools in the solid modeling menu.
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Isn’t that because Rhino is a surface modeller and the other are solid modellers?
Don’t get me wrong, I am all pro for having a single software that can work correctly with both, from an user perspective there shouldn’t be that distinction in the first place…
…Surfaces? Solids? polysurfaces? Breps? What are those?! Just make your 3D modeling tools work properly.
I guess I just keep expecting too much from technology… or capitalism? At this point I don’t know what is failing so hard for us to be honest.
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I surmise that you’re saying you’re joining separate surfaces at some point and creating a closed solid?
I prefer “solids” too or rather “step format” that programs like Mastercam can more easily interpret as “solid”.
But, I could also use “surfaces” or rather “iges format”, and even meshes or “stl format”.
Why not use modern surfacing tools in those other programs? And bypass Rhino completely?
So, those use “parasolid format”? which is just another permutation of B-rep’s? Hence “solid” meaning what? “Water-tight” B-rep’s?
If you have Solidworks then why bother with ProE, and if you have Unigraphics then why bother with Solidworks?
So you’re saying you join all those individual single-faced-brep’s into one “solid” multi-faced-brep? Then export?
By “solid modeling tools” you mean what exactly? Polysurfaces/multi-faced-brep’s?
Under what format? IGES? STEP?
IGES format or STEP format? And do you use a “CAD Exchange” program?
I think you’re misinterpreting what a “surface” is and what a “solid” is – imo.
No. “Surface modeler” vs “solid modeller” is relative. For example, IGES format typically wont translate from one program to another as “solid” data, but STEP format can.
It all depends are the composition of your geometric entities and how they are comprised. Some entities are compatible with STL, IGES, STEP, etc., and conversions and translations can cause transformations/distortions errors etc.
Without knowing the underlying nature of the maths behind geometric entities, how can your 3D modeling tools work properly?
Technology that isn’t understood is magic, while technology that is understood is obsolete.
Not exactly. Usually surfaces are trimmed and joined to form polysurfaces which can be trimmed and joined to form what is eventually a closed solid. The point being, its a way of avoiding the problems of which you were complaining.
To be clear, there are some tools in the solid menu that work OK. Making a sphere or cylinder works fine, but even those constructs can be made using the surfacing tools.
Not sure why you are talking about file formats.
My question was rhetorical. Rhino is a surface modeller, hence why one of its weaknesses are solid operations.
Solid modellers on the other hand make solid operations their strength while they have other weaknesses at which Rhino often excels.
More on this here: More Info on Solids in Rhino [McNeel Wiki]
I guess with that thinking we would never have home PCs with graphical user interfaces.
I don’t need to know any coding to run my pc, why would I need to know ‘the math behind geometric entities’ to make a fillet?
I just have to tell the pc to do it, I don’t need to know how it is doing it.
I am pretty sure that a 3D modeller that combines Blender/Cinema 4D + Rhino + Solidworks + ZBrush in one would be far from obsolete. But ok.
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