Fillet edge trouble

I’m having trouble filleting the inside outer edge of the curved frame in this model. Fillet
edge fails, and I’ve tried the pipe/split/blend trick but that fails as well. Any thoughts from the hive mind would be appreciated.
test fillet.3dm (155.0 KB)


Like this

or this (pipe trim trick)

test fillet.3dm (264.9 KB)

PS:I reduced your tolerance

Thanks, but not sure what you did exactly. What did you set the tolerance to? I get a piece hanging in the corner.


Yes then you trim the corner with a circle and sweep the two fillet edges along the 90° circular edge.

For the circle you need to set the CPlane to the surface.

You can safe yourself all this if you build your frame based on a true arc segment instead. Yes the long sides won’t have a planar top and bottom side but depending on what you’re designing that might not make a difference.

test fillet (1).3dm (391.8 KB)

Hi Dennis - if the object is to be constructed as smoothly continuous at the arcs, I would either make the arc the full width or, if the verticals must be separate and ‘beam like’ make sure they are tangent to the arcs - they are not

I get that if these are made from some kind of stock that may not be possible but assuming it is, I’d make the front and back from a single surface and trim out the inner part of the ‘window’

single surface

If those pieces need to be as they are, not tangent, then I’d go with Martin’s way…