Rhino5 for Mac: Fillet Edge has unexpected behavior on some shapes

I’m trying to fillet some edges of a surface using 1 unit for all of the edges being filleted.
Instead of doing what I would expect, the result creates a new surface inside of the original surface.
The result is a fillet surface inside of the original surface ( multiple surfaces ) instead of the fillet being applied to the original surface.

I can fillet a basic cube with expected results, but the shape in the attached image ( step-by-step ) does not behave properly.

I can work around this by setting the ‘tip’ of the fillet ( the bottom of the shape ) to zero, forcing the fillet to taper, but that’s not what I’m trying to do with the design.

Attached the file

ChairLeg.3dm (113.5 KB)

Hi Brandon - one problem is that your surfaces have stacked control points - let’s fix that, then work on the fillets. Hold on a bit.

@brandon - here’s a tuned up version - see how that works for you.

ChairLeg_PG.3dm (293.9 KB)


Thank you. I’m new to Rhino and am more comfortable drawing 2D in Illustrator and importing the curves in. I’m not familiar with a control point, but I’m thinking it may be similar to Illustrator’s “anchor points”.

I’ve attached the source .AI file as as well as a rhino file showing the progression from 2D profile to 3D shape.

legProfile.ai.zip (574.3 KB) ChairLeg Progression.3dm (162.1 KB)