GH Fillets, Rounds, Edge Blends, Radius, and Chamfer

Is there an easy way to do fillets and chamfers in Grasshopper? I’m asking for a friend:)

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This may help.

from what I know, grasshopper and Rhino are not amazing at fillets etc

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Check this topic.

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@HS_Kim and @calmunrogue,

Thanks for replying. I am still on Rhino 5, with Grasshopper version 0.9.0076 from August 2014:

That’s right, 2014! 2014! 2014, which is the latest GH plugin for Rhino 5. Common McNeal and associates, update the Rhino 5 GH plugin already. Anyway, the GH version for Rhino 5 does not have chamfers and fillets, to the best of my knowledge. These are very useful for solid modeling.

It has been updated, it needs a newer v5. We called it v6.

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“for a friend”

But you are right, chamfers got into GH1. There are no updates for Rhino5 anymore, because of the release of Rhino6/GH1.

incorrect. You can call the „rolling ball fillet“ functionality in Rh5 (gh 0.76) by script. I‘ve used it for years. The problem with this is that its pretty useless without more surface tools and knowledge about how to manually build corner blends, which then can be automated for a predefined logic/cell. Explaining this process would definitly fill many hours of discussion, because it requires a lot of background knowledge, both in surface modelling and gh.

This new added functionality in Rh6 is the equivalent to the _filletedge command. If you consider filleting as a post-process, there is no real need doing it in gh. However filletedge is a very generic command so there are many cases of failure. If you spend a lot of time of filleting geometry, it may also be a good investment to buy a cad software which can deal with this problem much better such as Catia/Creo or Solidworks. In my work of field, this is not always a solution so I‘m forced to reproduce a manual approach, however in 99% of all applications these programs yield pretty acceptable results.



Touche, my friend. McNeal sent me an upgrade offer for $399, but that got lost in the bulk mail. By the time I recovered it, the upgrade offer had expired. I’m thinking there’ll be another upgrade offer soon, so I wait…


Do you have some screen grabs to show how to go about doing “rolling ball fillet” commands via script? Ideally, a component will be really useful to noobs such as myself.

I don’t want to have to use another CAD program to do something I know should be fundamentally straightforward. The bake-and-trim approach doesn’t fit with my goal of doing all the design in GH and then baking to RH for 3D geometry export.

If the “rolling ball fillet” command is an advanced hack, then I don’t want to go that route.

Apparently the ability to do rounds, fillets, and chamfers in GH is not possible without RH6 (without your hack, anyway), which seems rather counter-intuitive to me.

I’m designing e-stop housings for my CNC router, and being able to have edge blends and chamfers in GH will help tremendously, especially because the housings will be 3D printed.

Hello, I have no access to Rhino right now. The (static) method you can call is:

Rhino.Geometry.Surface.CreateRollingBallFillet(…) ->3 overloads possible

Technically it means you can Fillet in V5. But as said, this doesn’t help you at all if you are not able to build corner blends due to missing surface tools and maybe skill. That’s just what I was saying. So it doesn’t make any sense to talk about it further.

Filleting is not intuitive nor a simple thing. Actually it is one of the most demanding tasks in surface modelling. And to be fair, Rhino 6 improved in automating this task, but its by far not comparable to Catia or other software yet. (both in manual - Catia Icem Surf or automatic - Generative Shape Design ).
Using Grasshopper for this is even with V6 the worst you can do. And the underlying _filletEdge command will fail quite often, depending on the complexity of your parts. This is nothing to blame McNeel for, because the topic is much more complex as you might think it is. But as said, if you spend weeks in filleting something Rhino and Grasshopper might not the right tool for it. But thats just my point of view. :slight_smile:


Hi Tom,

Thanks for having mentioned this solution.
I am actually facing up with a project in which I would like to use breps and I am looking for filleting in GH (Rhino 5). I didn’t know about the possibility to call a script (I have no knowledge in scripting), but I somehow figure out how to work with surfaces in order to make it works.

In the post linked below there’s an example of what you mentioned, but I don’t know how to make use of it.

Could you please give me a hint about the script?
This way I can study a walk around for automating fillets in my project.

Thanks in advance.


As I said, without a proper surface library this won’t help you much: (7.1 KB)

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