Shell with Multiple Rotation Axes

[Anonymous]

I have been unsuccessful thus far trying to model a particular shape, but I'm hoping there is way to do it in Archicad. The shape is probably most easily understood by looking at the attached images. The shell tool comes close to accomplishing the shape, so I will demonstrate with a shell for now:

1. Take a shell with extruded geometry (we want the building roof to be slightly bowed with upturned ends) the 3D image shows the shell before making the final transformation, which I have not been able to do
2. In plan view, bend the entire shell in the X,Y plane such that any section cut originating from the center point of the new curved edges (any section cut running perpendicular to the new curved edges) would result in a LEVEL portion of shell.

I have tried converting shells to morphs, and have not had success that way either. I believe this could be created with a mesh, but it would be tedious, time consuming to create and edit, and I'm not sure how smooth it would appear.

ANY HELP GREATLY APPRECIATED! Thanks very much
Kurt

[Anonymous]

Hi, after having the shell that way (like in pic 2) did you try going to the plan and changing the shell contour to the desire shape in like the lines in the last pic?

I don't understand exactly the shape you want to get, but probably that can help you

[sinceV6]

Hi.
Just changing the shell contour wont't give the desired results. It is the last step though. If you use the shell you have and just change the contour, you won't have horizontal cuts from radial sections because the shell is derived from a planar extrusion, and the contour and sections are cutting it at an angle. See attached, bottom left.

You need to build the extrusion radially, so you can get what you want. You need to trace the projected arcs outside the floor plan contour and build a ruled shell with the two distinct arcs. This should give you the desired results. Note that the shell is segmented, and you won't have perfect horizontal cuts (because of internal triangulation). Nevertheless, that's how I think you should make it.

1. Build a couple of 0 thickness walls before and after the floor plan projection.
2. I used some morph arcs to first build the arc profiles.
3. Using walls and arcs as planes and references, create a ruled shell.
4. Finally edit the shell contour in plan.

Check radial sections.

This is how I understood the problem. Not sure this is the wanted result.

Best regards.