# Fillet curves

**URL:** <https://discourse.mcneel.com/t/fillet-curves/1790>\
**Category:** Rhino Developer\
**Created:** [August 22, 2013, 4:04am UTC](https://discourse.mcneel.com/t/fillet-curves/1790 "2013-08-22T04:04:12Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![NiceDay](https://avatars.discourse-cdn.com/v4/letter/n/ce7236/32.png) [@NiceDay](https://discourse.mcneel.com/u/NiceDay)\
**Post date:** [August 22, 2013, 4:04am UTC](https://discourse.mcneel.com/t/fillet-curves/1790/1 "2013-08-22T04:04:12Z")

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HI  
I have two on\_curves and I’m trying to get the fillet points use RhinoGetFilletPoints,but I can’t get the fillet points. I want to fillet them with a specific radius.

 ![](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/1/e/1ec3f1a929cc50c915bb77a31b941af3e63daf6c.jpg)

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**Author:** ![John\_Brock](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/john_brock/32/476283_2.png) [@John\_Brock](https://discourse.mcneel.com/u/John_Brock)\
**Post date:** [August 22, 2013, 4:24pm UTC](https://discourse.mcneel.com/t/fillet-curves/1790/2 "2013-08-22T16:24:01Z")

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The two edge curves of that surface can’t be filleted because one is curved, so the fillet would have to be curves to stay on the bent surface.  
The two curves that are to be filleted have to be coplanar.

You could fillet the surfaces edges if the surface were flat, then bend it after Filleting the corner.

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**Author:** ![NiceDay](https://avatars.discourse-cdn.com/v4/letter/n/ce7236/32.png) [@NiceDay](https://discourse.mcneel.com/u/NiceDay)\
**Post date:** [August 23, 2013, 1:11am UTC](https://discourse.mcneel.com/t/fillet-curves/1790/3 "2013-08-23T01:11:00Z")

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thanks.

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**Author:** ![schultzeworks](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/schultzeworks/32/488974_2.png) [@schultzeworks](https://discourse.mcneel.com/u/schultzeworks)\
**Post date:** [August 23, 2013, 11:04pm UTC](https://discourse.mcneel.com/t/fillet-curves/1790/4 "2013-08-23T23:04:47Z")

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I have another hack-trick that has worked for me:

1. make a surface with extrude
2. offset the surface into a solid
3. fillet the four short / ‘vertical’ edges of the solid to the radius you want

You can now duplicate the edges (and join) if you still need the curves.

The process outlined by John would work, but the bend command might not be as accurate.

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**Author:** ![John\_Brock](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/john_brock/32/476283_2.png) [@John\_Brock](https://discourse.mcneel.com/u/John_Brock)\
**Post date:** [August 23, 2013, 11:13pm UTC](https://discourse.mcneel.com/t/fillet-curves/1790/5 "2013-08-23T23:13:14Z")

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Yes, I like schultzeworks’ method better.  
Instead of use the command name “Bend” I should have said Flow, making sure your target surface had the right curvature. Slicking through an extruded edge fillet is a more intuitive approach.

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**Author:** ![NiceDay](https://avatars.discourse-cdn.com/v4/letter/n/ce7236/32.png) [@NiceDay](https://discourse.mcneel.com/u/NiceDay)\
**Post date:** [August 24, 2013, 1:59am UTC](https://discourse.mcneel.com/t/fillet-curves/1790/6 "2013-08-24T01:59:40Z")

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In face I have only two on\_curves, not edges.

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**Author:** ![schultzeworks](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/schultzeworks/32/488974_2.png) [@schultzeworks](https://discourse.mcneel.com/u/schultzeworks)\
**Post date:** [August 24, 2013, 7:31pm UTC](https://discourse.mcneel.com/t/fillet-curves/1790/7 "2013-08-24T19:31:50Z")

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OK, the last hack was not especially clear. Here’s an another / better way to do it without as many surfaces and solids.

KEY : The sphere is built at the intersection of the two curves and is used to trim away an equal amount from both curves, no matter their angle or orientation.

 ![](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/c/a/ca676bb24d5dac9850c31247b5a619eae9be031a.jpg) 

I’ll do a demo of the same situation on a surface next.

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<div class="post-metadata">

**Author:** ![schultzeworks](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/schultzeworks/32/488974_2.png) [@schultzeworks](https://discourse.mcneel.com/u/schultzeworks)\
**Post date:** [August 24, 2013, 7:52pm UTC](https://discourse.mcneel.com/t/fillet-curves/1790/8 "2013-08-24T19:52:00Z")

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Here’s the original hack-trick, this time with both surface and solid commands. The fillet on your curved plane should be exact.

 ![](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/c/e/ce72c906fa3a89bfef894627b69d8f7523c49955.jpg)

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**Author:** ![pascal](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/pascal/32/479395_2.png) [@pascal](https://discourse.mcneel.com/u/pascal)\
**Post date:** [August 24, 2013, 9:34pm UTC](https://discourse.mcneel.com/t/fillet-curves/1790/9 "2013-08-24T21:34:00Z")

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Hi Dave- this is unlikely to help the ‘OP’ at the developer level, which is what this category is, but for just regular use in Rhino I made a script that fillets non-planar curves, [here][1].

-Pascal  
[1]: [http://wiki.mcneel.com/people/pascalgolay](http://wiki.mcneel.com/people/pascalgolay)