Sweep2 with maintain height is not maintaining height on a small object

[Young_Kim]

Hello,
Sweep2 with maintain height is not working on a small object. When I added few slashes the height went down a bit, but it still wasn’t the same height as the profile curve. Does anyone know why this is happening?

Attached is the file I used for this.
Sweep2 Maintain Height not maintaining height.3dm (660.7 KB)

Thank you.

[Tom_P]

dear @Young_Kim
i think you expect to much from a single _sweep2 surface.

if you need / want to stuck to a nurbs-Setting - maybe this is a starting-point:
do a
sweep2 (red) for the initial part
railrevolve with full profil (blue)
railrevolve with half profil (green)

this will still require some fine-Tuning with _setPt and _matchSrf

for sure a sub-D approach will be possible and faster - but maybe a bit of topic ?

kind regards -tom

[pascal (Pascal Golay)]

Hello - Sweep2 will look better if you put a small cross section curve at the small end rather than the converging rails.

-Pascal

[Tom_P]

there is also some similar topics -

C Scroll surfaces

Hi John- the way your original curves are set up, one hits the planar area ‘hard’ with a sharp corner, and one dips slightly behind then comes back to the planar area. I cleaned up the latter but left the hard intersection as this seemed to be part of the design. I would make that intersection planar as well, myself, and avoid that slight kink at where the scroll meets the flat. -Pascal

How to create this shape?

I need to model the ceiling panel in the attached image. I have two areas I’m struggling with here. First, how does one create the converging arc shapes that are increasingly wider as they spread? Secondly, how does one then have those shapes extruded with an increasing thickness as it gets to the middle of the circular shape? Thank you.[51%20PM]

but there was a newer one - i cant find - i tried:
acanthus ? helix ? spiral ? scroll ?

[Young_Kim]

@Tom_P That works to create the shape. Very easy to understand. Thank you for the suggestion
I was wondering if my Rhino program file was corrupted or something since maintain height wasn’t working. When I scaled the curves much bigger the maintain height worked perfectly though.

Best

[Young_Kim]

Thank you for your advice