Weird sweep2 result

So I guess I made the top right surface in Alias once upon a time (I can’t find it anymore and I no longer have a license for it anyway and possibly this export has been changed through Solidworks), because when I try now in Rhino, the surface blows up like a balloon:

Anyone have any strategies around this, or should I be using something other than sweep2?

rail2.3dm (105.4 KB)

Hello- this feels like a Sweep1 to me

-Pascal

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:man_facepalming:

Thank you! :blush:

Any idea why the sweep2 “inflates” the way it does, though?

Well, the sweep sections are simply scaled and rotated across the gap - there is no information, as far as that command is concerned, to tell it what goes on in between. NetworkSrf also does some better thinking about what the shape should look like, it does not just create sections the way Sweep2 does.

-Pascal

I just noticed two things:

First, it’s a bit weird that the dialog uses radio buttons, yet no option is selected (or can be selected) in the “frame style” and for me, the buttons don’t look disabled…

image

Second, there’s no easily accessible non proportional viewport scaling in Rhino so I had to scale up the object itself and mirroring it across the X axis there’s still som ballooning happening, even though the rail is planar…

I hate those blow ups as well. they are counter-intuitive.

_edgeSrf
_matchSrf (3 times: long edge: G2, side edges G2, long edge G1)

will give a cleaner surfaces.
additional cv massage might even improve the result…

@pascal
would love to see a sweep2 option or new surface command that allows a fixed spacial orientation of the shapes / sections of a sweep2.

similar to extrudeCrvAlongCrv
something like extrudeAndScaleCrvAlong2crvs ?

the option for sweep2 could be the same / similar as “planar Sections” in _blendSrf

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