Fillet curved edge of polysurface

handle.3dm (194.8 KB)

what is the best way to fillet the curved edge of this polysurface?

Fillet surface command, then delete fillets, blend surface command, extract iso curves from these, delete blend surface, then sweep 1 rail using your extracted iso curves and surface edge, it kind of worked when I gave it a quick go, but I did notice your original curves which you created your surfaces from aren’t particularly good, there’s a kink in the middle where you have mirrored the original curves, i think this will be problematic when trying to create smooth fillets

Hi Revel - I’d clean up the curves first - the curves you have off to one side are very complex, and the two halves are not tangent to one another - making a clean simple curve with good continuity across the mirror plane will simplify your life a lot when it comes to making the solid and filleting etc.

handle _pg.3dm (362.3 KB)


thank you. so, here is the reference curve, originally a .123D file that I imported as a .dxf- a very faceted curve that could use some smoothing. what is the best way to make this into a good rhino curve sufficient for doing the aforementioned fillet? I believe I have been tracing it with a control point curve, which evidently is not the way to go.

as with all of my rhino modeling so far, this is to be 3D printed, fwiw.

thank you,


handle curve.3dm (62.4 KB)

Hi Revel - for curves that have simple shapes like this you can just draw a control point curve, I’d use degree 5, and move points around, InsertControlPoint/RemoveControlPoint as needed to get really close and have your curve be simple and with good curvature progression:

In this case I used Symmetry with History on to get the left half updating to edits on the right, and tangency held across the symmetry plane.


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whoa cool! thanks man:smile_cat:

that worked.
initially I had an issue with trimming the leftover naked edges. I resolved this by exploding before excecuting the filletSrf command, then using individual polysurfaces to trim before joining it all back up to a closed polysurf.

@pascal did you manually set tangency across symmetry line?

Thanks again for the help,


Hi rev - I set the tangency using the Symmetry command but it is also perfectly possible and easy to set the tangency across the mirror plane by hand or with Match > Average checked.
But, if your goal is a soft ‘feely’ shape, there are better, or alternate, ways to do this than fillets.

handle curve_PG.3dm (231.3 KB)
Move the blue curves vertically to adjust the softness of the ‘fillet’.


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