topic Re: Shell edge angles in Modeling

Shell edge angles

Paul King — Tue, 23 May 2023 12:33:05 GMT

Hi - I have never really gotten my head around shells, as they so seldom apply in the situations I tend to encounter - however I do have a situation now where I want a vaulted composite ceiling. The shell tool would seem to be ideal for this, except the edges of any shell I create (using simple extrude method) are always at right angles to the surface, whereas I want a vertical cut, much like you get with roof edges. The only edge related adjustment I can find in the pet pallet is an incomprehensible 'edge type' - which seemly makes no geometric difference at all to edges.

How (apart from Boolean cutting) can I achieve vertical edges?

Also, if I want different shells to display at different resolutions, how can I do this? I can't see a way to adjust the number of facets that are used to represent curved surfaces at all, (magic wand settings makes no difference), and shallow vaulted ceilings look rather crude when 4 asymmetrically arranged facets are used to represent the arced profile .

See attached cross section. The dotted red arc with vertical lines each end represent the profile required, as compared with the very best the shell tool can seemingly deliver (?)

Re: Shell edge angles

Barry Kelly — Mon, 16 Dec 2013 01:43:05 GMT

Making the shell slightly larger than you need and then defining a shell contour will give you vertical edges.

As for the resolution of the curves it can be changed with a registry setting but is will only affect your machine - the same file on another machine will show the old resolution unless the registry is changes there too.

I would try using a complex profile wall or beam if you can as you will have much better control of the curve resolution.

http://archicad-talk.graphisoft.com/viewtopic.php?p=222545

Barry.

Re: Shell edge angles

Paul King — Mon, 16 Dec 2013 07:26:16 GMT

Thanks Barry.

Insane that the shell tool, after all that development time, is still useless for practical purposes for lack of simple built-in curve resolution and edge controls....

Re: Shell edge angles

Josh Verran — Thu, 05 Nov 2020 02:41:53 GMT

Has there been any development to this since 2013.
I've come up against the same issues that are in this original post, but can't see how to resolve.

Re: Shell edge angles

Barry Kelly — Thu, 05 Nov 2020 02:55:15 GMT

Josh wrote:
Has there been any development to this since 2013.
I've come up against the same issues that are in this original post, but can't see how to resolve.

With the pet palette now, we do have the option of adding more nodes to the arc.
More nodes will give a smoother effect.

Barry.

Re: Shell edge angles

DGSketcher — Thu, 05 Nov 2020 09:51:33 GMT

@Josh, Your other option is to draw the curve with an Arc / PolyLine and then play with the Magic Wand settings before using it to draw/trace the shell profile. Whichever method you adopt, either this or the complex profile suggested by Barry, you will never have a visually true curve. The best you can do is to make the faceting small enough that it doesn't distract the client or overload the rendering process.