On 4/16/2021 12:34 PM, William F. Adams via Discuss wrote:

OpenSCAD has decent, perhaps not great, list support.

What it doesn't have is any way to extract geometry information out of
constructed objects.

That is, you can describe a cube like so:

 c = [
    [       // points
        [0,0,0],
        [0,0,1],
        [0,1,0],
        [0,1,1],
        [1,0,0],
        [1,0,1],
        [1,1,0],
        [1,1,1]
    ], [    // faces
        [0,2,3,1],  // left
        [0,4,6,2],  // bottom
        [0,1,5,4],  // front
        [1,3,7,5],  // top
        [4,5,7,6],  // right
        [2,6,7,3],  // back
    ]
];

polyhedron(points=c[0], faces=c[1]);

and do whatever you like to the points before you hand them to
polyhedron(), but if you use a primitive to construct your cube:

cube(1);

then you can't get any information whatsoever about it.

For the kind of project you're talking about, I would define each slab
as a module, and then I would assemble those modules twice, once to form
the finished object (so as to check fit and look) and once to form the
as-printed components.  (Or, in your case, as-cut.)

There are other similar techniques.  One that I've used is to have two
translations and two rotations for each piece, where one
position/rotation is the as-assembled position, and the other is the
as-printed position.  It's then not too hard to animate between the two,
so that the pieces fly from the print bed to the constructed model and
back again.

On 4/16/2021 2:16 PM, Jordan Brown wrote:

Like so, if I've got the attachment right:

I don't make lists of parts in scad, I form then into structured assemblies
using modules to represent each level:

[image: image.png]

Since all the panels are created parametrically I always have access to
their dimensions, so laying them out for cutting is just a matter of
translating using those dimensions and rotating. When I press F6 I draw the
laid out dxfs instead of the assembly view using $preview:

[image: image.png]

Python scripts then export all the dxfs and stls, etc. In this case
the framework makes spine.dxf and table.dxf by calling spine.scad and
table.scad that it finds in a panels folder. It gets a list of dxfs from
the BOM information emitted by echo statements and can work out that, for
example, table.dxf covers z_table.dxf, brace.dxf and spar.dxf, so they get
removed from the folder of files to be routed and replaced by table.dxf.

There is nothing automatic about the layout because how I group things for
cutting depends on my stock sizes as well as build order, etc, but once
coded everything adjusts itself if the dimensions change.

On Fri, 16 Apr 2021 at 22:34, Jordan Brown openscad@jordan.maileater.net
wrote: