I am not the best person to weigh in here; however, geometric patterning would
most likely be accomplished easily with parametric software like openscad
(http://www.openscad.org/).
From: hackpgh-discuss-bounce@xxxxxxxxxxxxx
[mailto:hackpgh-discuss-bounce@xxxxxxxxxxxxx] On Behalf Of Andrew C.
Sent: Tuesday, January 31, 2017 1:22 PM
To: hackpgh-discuss@xxxxxxxxxxxxx
Subject: [hackpgh-discuss] Re: Wrapping 2D geometric pattern to 3D hemispheres?
Here's an example of what kind of thing I mean to do with those patterns, this
should make it clear:
https://www.pinterest.com/pin/489414684479292312/
How did they model that? It can be a flat geometric pattern, but it's wrapped
to a sphere perfectly.
And if you look- it really is a true sphere- it's not a polyhedron. That's
exactly the kind of thing I want
to make my own custom models like with my own patterns.
Can anyone tell me what software was used? Free or otherwise? I do have
Inventor 2010 to use.
And Fusion 360 if I learn it I suppose.
Surely there's a way to do this. That's the exact kind of effect I want.
On Tue, Jan 31, 2017 at 1:10 PM, Andrew C. <soshumasamune@xxxxxxxxx
<mailto:soshumasamune@xxxxxxxxx> > wrote:
If you want sharp internal corners- you cannot get them with the cnc. Rotating
cutters leave radii in corners.
Assuming if shoji screens, you use traditional material- wood. Thats done on
laser cutter.
As for my design- you know that green lacework 3d printed skull on our shelf at
hack? I want to do something like that- where the lacework is a specific line
width and pattern from 2d.
Yes- to anyone that reads this- there are plenty of searchable google posts on
this. But none of them have answers!
Im certain theres a simple way to do this in some software- where are all our
3d modelling gurus?
On Jan 31, 2017 12:40 PM, "Steven Owens" <stevenjowens@xxxxxxxxx
<mailto:stevenjowens@xxxxxxxxx> > wrote:
A useful forum discussion:
http://www.plasmaspider.com/viewtopic.php?t=9780
On Tue, Jan 31, 2017 at 12:33 PM, Steven Owens <stevenjowens@xxxxxxxxx
<mailto:stevenjowens@xxxxxxxxx> > wrote:
Sweet patterns. I've been thinking, lately, of maybe making some
shoji screens and the like with the CNC router, cutting out multiple
panes like this and fitting them into a frame.
I don't know much about CNC patterns, but I can give you some general
advice based on stuff I've learned in leatherworking and etc.
There are basically three ways I can think to do it.
Curved Triangles
First, if you want to map a flat surface to a sphere, you need curves.
For example, if you make a triangle with concave edges (is there a
word for that geometric shape?), with the right amount of concavity,
when you wrap the triangle around the sphere, the edges will lay
smooth and flat.
On the flip side, the standard way to make a leather skull cap is to
make triangles with convex curves. Surprisingly I can't find a
pattern for this in google, but it's pretty straightforward. Ah, this
isn't precisely the same, it uses asymetric triangles, but it gets the
idea across:
http://www.instructables.com/id/Sew-a-Welders-Cap/
Orange Peels
Another way to make a cup shape with leather is to cut a circle, and
then cut "darts", thin, triangular cuts out of the perimeter. Then
you fasten the edges of the darts together, and that pulls the whole
thing into a cup shape. However, this doesn't work as well with rigid
materials.
But when you push that dart approach to the extreme, you basically get
the orange peel pattern, which *should* work with rigid materials.
Like this:
https://forum.solidworks.com/servlet/JiveServlet/downloadImage/2-368211-87918/450-234/orange-peel-real-map.jpg
From this forum discussion:
https://forum.solidworks.com/thread/69471
Icosahedral
The third way is basically to make some variation on a dodecahdredon,
isododecahedron, etc. In essence, the shapes used for the more
complicated/spherical RPG gaming dice.
The Traveler roleplaying game (science fiction/space travel) magazine
(Traveler's Aid) used to have articles about new planets, using an
"icosahedral" design, a combination of this and the orange peel
approach; basically an orange peel made out of hexagons, so you could
photocopy it, cut it out, and tape it together into a roughly
spherical shape:
http://roleplay-geek.blogspot.com/2011/12/rpg-mapping-tools-part-4-planet-and.html
Hinge Pattern
With any of these approaches, you'd design the larger shape, then fill
each area with a hinge pattern. Now we're getting way outside my area
of familiarity, but some googling turns up this really cool
multidirectional hinge pattern:
http://www.instructables.com/id/Super-flexible-duble-curvature-surface-laser-cut-p/
Steve
On Mon, Jan 30, 2017 at 3:36 AM, Andrew C. <soshumasamune@xxxxxxxxx
<mailto:soshumasamune@xxxxxxxxx> > wrote:
So I have a geometry modeling problem.
I've had an idea for some parts I've wanted to model for years now, and 3D
print-
but they involve some weird tricks I don't know how to do, or even where to
start
looking to solve this.
I want to take some 2D geometric patterns, like the one for example on our
living
hinge mousepad at the laser cutter, and wrap them in 3D to the surface of a
hemisphere,
or even a full sphere. The hemisphere would be a shell, maybe 1/4 of an inch
thick,
the solid lines on these patterns would be the solid portion of that
hemisphere- the
gaps between would be open to see through.
I have not found any answers on how to do this, or software needed, or if it
is possible.
I have done a lot of 3D modeling, but not found a way to do this.
Anyone know how this can be done?
The shapes printed would be printed in PLA or wax- they could be cast in
metal afterwards.
I'll attach an example image of a couple of the patterns I had in mind. The
idea in the
end are latticework lanterns, using arabic and Japanese traditional
patterns.
-Andrew C.
--
Steven J. Owens
stevenjowens@xxxxxxxxx <mailto:stevenjowens@xxxxxxxxx>
puff@xxxxxxxxxxxxx <mailto:puff@xxxxxxxxxxxxx>
412-401-8060 <tel:412-401-8060>
