It boggles the mind that the same issues are still present over a decade later

I started with Rhino probably 15 years ago and fell in love with the command line aspect of it, but it drove me nuts when operations would fail for seemingly no reason and I grew tired of endlessly having to recreate geometry a slightly different way to get certain operations to work, mainly boolean or split/trim.

Every few years I’ll pop back over to it, check out the demo, only to find the issue persisting if not getting worse, so I give up on the idea of buying the latest version and go back to AutoCAD. I’m not a fan of how Fusion360 is laid out at all, but it works. No matter what, it just works. Try to fillet an edge in Rhino if there isn’t the required radius on all surfaces and you get surface spaghetti. Try that in F360 and it is intelligent enough to taper it.

I just decided to give it another go and put together a simple Nintendo Switch-like shell and I’ll be dammed if I haven’t spent more time rebuilding geometry or exploding closed surfaces to do something that I should be able to do as a solid.

Now I have hit a point with the model that I can no longer work with it. I can’t split it, I can’t difference it, really I can’t do anything with it unless I blow it apart and tediously and painstakingly work with individual surfaces, and that’s just not productive.

I want to give you my money. I want to buy Rhino again. But I am genuinely dumbfounded as to how people produce manufacture-ready products with Rhino.


Sounds like you might be better off with a solid modeling software if the idea of working with surfaces seems cumbersome. Rhino is not meant to compete in that arena as there are many capable solid modeling products already available.



my crystal ball says you will get help if you’re able to post your geometry along with a description what fails.


Hi @greg.johnson,

If you are unable to post your geometry on this forum, you might consider starting a conversation with our technical support staff at


– Dale

Thanks for the reply @DanBayn. I love parametric modeling, but I love the interface of Rhino. I would say I model with surfaces in mind more than solids, it’s just that I used closed polysurfaces because my models are almost always 3d printed so proper geometry is important.

It just gets wildly frustrating when I can’t filletEdge and instead need to make a negative mold and boolean difference. And then when that doesn’t work, I need to move the geometry by .01mm to get it to work. Those are pains in my neck I can kind of live with, but the issues compound as the models get more complex so when I get to a point that no ‘tricks’ will work, I have to take my splines and isocurves and remake the geometry entirely.

Then there are cases where I simply cannot achieve the desired effect. Here is a good example of an issue I am running into right now that is super common.

Granted I end up with a cleaner model every time I have to redo it, but at what cost and to what end?

Edit: I didn’t realize replies were not inline. @dale and @clement, pasting geometry for this project publicly is out of the question, but I have uploaded avideo showing my issue. This is a crazy common occurrence, so finding a solution to this would go a long way to alleviating my frustrations.

Hi @greg.johnson, never do this. It will make your problems worse. Same counts for fiddling with the tolerance settings when surfaces cannot be joined to closed object.

The problem you see with the chamfer does not look like a showstopper imho. You might simply delete the half way done chamfer using _ExtractSrf then use the same command to get the surrounding surfaces. _Untrim them so you can get back to the state before the chamfer has been applied. Then join everything up and try to make the chamfer along the splitted edge, make sure to select both edge segments so the chamfer covers the whole edge.

The way you tried to append to the existing chamfer by just creating another one and then trying to intersect that to get some trim edges cannot work. If you want to do it like that, you’ll have to extend the failed chamfer surface edges so you get a clear intersection which results in some curves. Of course doing it this way brings you back to the surface modeling level.

To stay within the solid modeling level, always check the results after using _ChamferEdge or _FilletEdge. If things fail, it is often better to undo and find out why, instead of continuing and making things probably worser. btw. when _FilletEdge fails i often was able to get things done using _FilletSrf with Trim=No and Extend=No, then extract the required edge curves from the fillets and use these to trim back the problematic surfaces. But thats surface modeling again, which is Rhino’s strength…


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@clement, the only reason it is partially chamfered is because those are the only lines that would chamfer. I got the same results when trying to chamfer those problem lines first.

As for moving my geometry, it’s the only thing that works sometimes. I can probably recreate an issue I had to solve last night by moving a negative plug instead of a simple filletedge.

edit: What is the difference betwen ChamferEdge and _ChamferEdge?

From the Rhino helpfile:

_ Runs command as English command name.

Rhino can be localized in many languages. The non-English versions will have commands, prompts, command options, dialog boxes, menus, etc., translated into their respective languages. English commands will not work in these versions.

For scripts written in English to work on all computers (regardless of the language of Rhino), the scripts need to force Rhino to interpret all commands as English command names.

As for the geometric problem, if you could post the relevant surfaces, i think someone would be able to help you out so you could skip doing it with (con)fusion 360 and stay with Rhino :wink:


@clement, You really just changed the way I look at my models in Rhino with ExtractSrf. I have never used that command before. ExtractSrf combined with PlanarSrf seems to be allowing me to resolve most of my issues. With your one simple comment I have changed the way I look at objects in Rhino completely.

Is there a command like PlanarSrf (not Patch) that will create a surface that bends on two axis instead of just one? Basically a command that would prevent me from having to extrude a curv and then split it where it intersects.

Does Rhino have an intelligent way to simplify/rebuild a surface with smallest number of UV points?

And I agree, F360 is confusing as all get out. The interface is absolutely awful and I hate nearly everything about it. Dealing with imports is obnoxious as well, and I work with a ton of files from digikey (most of my modeling stuff is fun little electronic projects).

(con)fusion 360

I almost laughed out loud when I read that.

Have a good weekend,



Thank you @greg.johnson, that is great. But i really wonder how you could get along the last 15 years without ever using _ExtractSrf ? I would really miss it.

Hard to say without seeing what kind of surface you’re trying to create. Maybe _Sweep2 ? The splitting or trimming often has to be done in an extra step, either with curves or other surfaces. I have to admit, i realy like to do surface modeling, using just solids is handy too but when things get more detailed, you’ll often have to access and attack the surfaces individually.


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The way I approached modeling was just very different than how you approach it. For instance, I almost never use tools like Loft or NetworkSrf. I also absolutely hate Bend and Stretch because of how imprecisely it draws the surfaces. But now with ExtractSrf, I feel I can make use of a lot more functionality that I just kind of ignored before.

Lightbulb moment.

Hey Greg,

Let me share my take on modeling work, not defending Rhino, but just an approach that works well in Rhino, also in Alias, NX advanced surfacing, or Catia (Ive never used Catia, but based on peers experiences).

In most of our work we use patches made out of 2 clean curves, usually single span if we can, with matching degree, point count and relative position of those curve points along the surface. We use those as inputs to make surfaces with the EdgeSrf command. Then we ChangeDegree on the cross (V) direction to degree 3 or 5 and that adds more points evenly. Then we ‘curve’ that direction by using the MoveUVN interface. Along with Smooth (with locking boundaries checked) to get clean and smooth curvature. Then tools like BlendSrf and MatchSrf also help for neighboring patches continuity. The new option in V6 for BlendSrf at creation and EndBulge after the fact editing are also great. And history, in a few instances is also helpful.

We also do a lot of early exploration in SubD, not in Rhino, and then import that fast, cool but bumpy stuff in to do the process above described in Rhino for clean rebuilds. For the last decade or so we do most of our explorations in SubD. Nurbs is a complete waste of time for this, and I think it’s only used by people who haven’t ventured into SubD to expand their skills, or who do not need to do fast iterations and explorations and focus only on the one-shot final/cleaner output of Nurbs.

We are designers, and we really obsess about form, and I can’t even think how we could get any work done in a solid modeling app, even the ones with some limited surfacing like Fusion360, which we use for some internal nick-knacks and for import/export to client files. F360 does have more capability with Tsplines but I personally find it slow to work with, unreliable and very ugly in its end results.

I can’t imagine using a solid modeler more intensively for our work. For example: Modeling with fillets is a total hack in my opinion, ok to do internal mechanical components, something fast, or for a quick 3D preview of stuff to be rebuilt later. Never acceptable to do something visually pleasing, or to release for tooling. Same goes about the standard solid modeling tools like extruded, lofts, and Booleans. It all looks like a Solidworks tutorial to me.

Rhino is in a class so above all the simplistic (but robust) B-Rep solid modeling packages, that unless you can embrace their optimal modeling approach you will think it’s a toy. Most people using solid modeling think that way, but that’s because they don’t know what they don’t know, and because they are happy modeling and editing numerically simplistic prismatic shapes or questionably acceptable topology when they try to get fancy. I also think that for many tasks, parts, and industries the level of modeling you can achieve in a solid modeler is just fine. So I don’t want to sound elitist. They do very different things for a very different audience of users and clients.

I hope this helps, maybe try some of the tools and techniques I mentioned and see if the expand your horizons a bit more. The problem with these workflows is that they are hard to do and mostly undocumented. And like someone at McNeel once told me: “The people who know how to do the stuff are too busy to share it”. I feel guilty of this, and at least I wanted to chime-in with a few pointers while I’m laying on my couch taking a break from ‘doing the thing’.



PS: Dear McNeel people, do not misinterpret this post as praise. I’m just thinking out loud. We’ll be back to your regular beatings on Monday :crazy_face:


Hey Gustov,

As much as I hate to admit it, this describes me quite well!:

Cheers! … Chris

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Hi Greg,

I am curious if you know about any any video tutorials/courses (paid or free) that go into these workflows you talk about in detail? How did you end up learning these?

I would love to explore this subd to rhino workflow that you mentioned.