Wow, that's a very nice idea.

close the surfaces, so I just left it with a solid shell.

> I'm working on a lattice implementation that might work in OpenSCAD.

>

> The problem is closing off the outside of the lattice so you don't

> have dangling strut ends.

> My idea is to construct the following shapes:

>

> target = Benchy, or whatever shape you want to make a lattice from

> basic_lattice = the Kelvin cell lattice, with struts of diameter d

> basic_mesh = the Kelvin cell mesh, with polygonal walls of thickness

> d. It's a proper 3D object made by thickening the walls of the

> non-manifold object I described in my previous post.

> internal_lattice = intersection() { basic_lattice; target; }

> lattice_shell = intersection() { basic_mesh; shell(d) target; }

>

> The internal_lattice is the version of the lattice with dangling strut

> ends. The lattice_shell connects those dangling strut ends into a

> connected lattice.

>

> the final result is: union() { internal_lattice; lattice_shell; }

>

> The trick is to figure out how to create a nice looking lattice_shell

> that closes off the dangling struts.

> With my current implementation, I'm getting something close to what I

> want, but it's not quite right yet.

>

> The operation 'shell(d) shape' is something you can implement in

> OpenSCAD using minkowski.

>

http://jweoblog.com/?p=644>

http://forum.openscad.org/make-an-object-hollow-with-constant-wall-thickness-td14255.html>

> (I'm prototyping this in Curv, but am hoping the final version could

> also be written in OpenSCAD. That's why no code.)

>

> On 30 June 2018 at 11:21, doug moen <

[hidden email]> wrote:

>

> > In principle, what you want is to create a Kelvin cell mesh. It's a

> > mesh because it's made of polygons joined at the edges. But this is

> > a volume filling mesh, not a surface mesh, so it isn't 2-manifold.

> > Then you intersect the Kelvin cell mesh with Benchy. Then you take

> > the resulting volume mesh, and turn each resulting polygon edge

> > into a strut (eg, a cylinder). So that process takes care of

> > repairing the boundaries of partial Kelvin cells.

> >

> > But, I don't know how to do this in OpenSCAD using high level

> > operations. This kind of volume mesh is not compatible with the

> > CGAL intersection operator. And after you perform an intersection,

> > you don't have programmatic access to the edges of the resulting

> > mesh.

> >

> > You could program this in OpenSCAD at a low level, working directly

> > with mesh data structures, but then I don't see any benefit of

> > OpenSCAD over a general purpose language with better support for

> > data structures.

> >

> > On 30 June 2018 at 10:04, adam purdie <

[hidden email]> wrote:

> >

> >> That was my first thought and i gave it a go but there was no way

> >> to ensure that the cells were all complete, most of the cells on

> >> the edges were all partial which would be ok except the cells are

> >> only strong when they're complete.

> >>

> >>

> >> On Sat, 30 Jun 2018, at 11:40 PM, doug moen wrote:

> >>

> >> Well, suppose that you create a Kelvin cell lattice structure, and

> >> then you combine this with "benchy" using either intersection or

> >> difference. Is that a good description of what you are trying to

> >> achieve? If so, then it just becomes a matter of how to write code

> >> to create the lattice.

> >>

> >> On 30 June 2018 at 08:55, adam purdie <

[hidden email]> wrote:

> >>

> >>

> >> Greetings! i've perused the OpenSCAD forums but not posted before.

> >>

> >> I'm trying to figure out how to use OpenSCAD to create s say a

> >> cube or a wall but make the lattice of only the complete contents

> >> of another. Similar to the "pattern" feature of meshmixer.

> >>

> >> Basically i want to be able to take any complex or even an

> >> imported STL and make it be "made of" whole kelvin cells like this

> >> -

https://pressurevesseltech.asmedigitalcollection.asme.org/da> >> ta/journals/jpvtas/28540/029004jpv1.jpeg

> >>

> >> I can figure out how to make it work for simple shapes with known

> >> geometries but not with complex shapes like benchy.

> >>

> >> Any suggestions? can this be done with openscad? cheers!

> >>

> >> _______________________________________________

> >> OpenSCAD mailing list

> >>

[hidden email]
> >>

http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org> >>

> >> *_______________________________________________*

> >> OpenSCAD mailing list

> >>

[hidden email]
> >>

http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org> >>

> >>

> >>

> >> _______________________________________________

> >> OpenSCAD mailing list

> >>

[hidden email]
> >>

http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org> >>

> >>

> >