topic Re: Shell Tool Curved Geometry in Modeling

Shell Tool Curved Geometry

Josh Verran — Mon, 26 Jun 2023 01:37:59 GMT

I'm trying to create the below geometry using the Shell tool.

I can almost get the shape I'm after, but cannot curve the two longest sides as dashed below.

Hoping someone can please give me some guidance.

Lingwisyer — Mon, 26 Jun 2023 07:11:36 GMT

As far as I know the Shell Tool iteself cannot do this. You can only curve and pitch the two ends. I would just SEO it with another shell.

DGSketcher — Mon, 26 Jun 2023 07:43:11 GMT

This tutorial in the help may offer a solution...

Fermat — Mon, 26 Jun 2023 12:35:45 GMT

You can just select the shell, right click and choose "Create Hole in shell".

Once that you placed the hole you can even select the hole by Shift + clicking on the edge generated by the hole itself:

this way you can Edit the perimeter of the hole, rotate the geometry or even modify the "Extrusion Depth" of the cut volume.

Unfortunately you can't do everything you can do with Rhino, for instance, but probably this could work for your case!

Lingwisyer — Tue, 27 Jun 2023 01:56:54 GMT

But holes and the contour are vertical crops? Given the plan and elevations given, we need a horizontal crop... or can those be rotated too?

Barry Kelly — Tue, 27 Jun 2023 02:21:06 GMT

I think the top perimeter crop in this case is fine.

The problem with Josh's model is that it seems to curve along 2 axii.

From A-A to B-B is a simple 'ruled' shell, transitioning from a flattish curve to a deeper curve along a flat (but sloping) axis.

That bit is fine.

But from the axis to each side it is transitioning from a flat profile(the axis) to a curved profile.

This could be done with 2 shells joined end to end at the axis.

The problem is, you can't combine both of the transition (from left to right and side to side) at the same time.

So there is a double curve in the element that I don't think Archicad can do.

Well it probably could as a morph, but I am not sure how you could manipulate it easily.

And there are also 'Nurbs' but this has to be programmed in GDL.

Or use a mesh and set the top heights as desired, duplicate it, drop on slightly and Solid Element Operation with subtract to get the thickness.

Possibly it could be modelled in another software and then imported into Archicad.

Barry.

Josh Verran — Wed, 28 Jun 2023 19:39:43 GMT

Thanks for the tips and guidance guys.
I have some paths to consider.

I'm getting some usable results from the Rhino-Grasshopper connection, once/if I resolve it, I'll post results here.