Gas station without pumps

2019 August 10

More large pendants

I’ve previously posted about my 3D-printed stage jewelry: the 3D slugs , the diamond, and the chain of office, printed on my Monoprice Delta Mini printer using CC3D Silk Gold PLA filament.

I’ve done a couple more designs since then: two more large pendants that could be used with a chain of office.  These were designed for fairly fast printing, being fairly thin:

Flower pendant 1 has 12-fold symmetry (including mirror symmetries).

Flower pendant 2 has 16-fold symmetry, including mirror symmetries.

Both pendants were simple OpenSCAD code, as they consist of unions and intersections of spheres (cut to just the positive-z half-space, to get a flat back).

```// Flower pendant 1
// 12-fold symmetry
// bumps in center
//

// Kevin Karplus
// 2019 Aug 1

module round_facet(r=15, h=5)
{
\$fa=2; \$fn=60;
intersection()
{   cylinder(r=1.3*r, h=h);
union()
{
difference()
{   sphere(r=r);
carve_r=1.8*r;
rim_h = 0.4*h;
raise = sqrt(carve_r*carve_r + rim_h*rim_h -r*r)+rim_h;
translate([0,0,raise]) sphere(r=carve_r);
}
inner_r=0.35*r;
translate([0,0,h-inner_r]) sphere(r=inner_r);
}
}
}

n=6;
r=40;
for(i=[1:n])
{   tran=0.3*r;
color(c=[i/n,0.1,(n-i)/n])
translate(tran*[cos(360*i/n), sin(360*i/n),0])
round_facet(r=r-tran,h=0.3*(r-tran));
}
```
```// Flower pendant 2
// 16-fold symmetry
//

// Kevin Karplus
// 2019 Aug 2

module round_facet(r=15, rim_h=2, carve_ratio=1.7)
{
\$fa=2; \$fn=60;
intersection()
{   cylinder(r=1.3*r, h=rim_h*2);
difference()
{   sphere(r=r);
carve_r=carve_ratio*r;
raise = sqrt(carve_r*carve_r + rim_h*rim_h -r*r)+rim_h;
translate([0,0,raise]) sphere(r=carve_r);
}
}
}

module flower(petals=6, r=40, height_ratio=0.07, translate_ratio=0.4, carve_ratio=1.7)
{
for(i=[1:petals])
{   tran=translate_ratio*r;
color(c=[i/petals,0.1,(petals-i)/petals])
translate(tran*[cos(360*i/petals), sin(360*i/petals),0])
round_facet(r=r-tran,
rim_h=height_ratio*r,
carve_ratio=carve_ratio);
}
}

flower(petals=8, height_ratio=0.08);
```

I have not released these designs on Thingiverse, because the site keeps being unresponsive when I try to upload new designs. I realize that I shouldn’t complain about a free service, but I’m about ready to give up on Thingiverse. Is there a better 3d-printing sharing site?

Update 2019 Aug 10: Thingiverse finally let me upload as https://www.thingiverse.com/thing:3802142 and https://www.thingiverse.com/thing:3802138.

1. […] posted about my 3D-printed stage jewelry: the 3D slugs , the diamond, the chain of office, and large pendants printed on my Monoprice Delta Mini printer using CC3D Silk Gold PLA […]

Pingback by Star-of-stars, another large pendant | Gas station without pumps — 2019 August 11 @ 13:47

2. The “new” (last few years) owners appear to barely care about keeping thingiverse alive. Prusa have their own version, but really meant for their printers it seems. I’ve taken to checking my designs into git repositories and linking to them from thingiverse and blogging about them so that they are still discoverable when stratasys gives up.

In the meantime, I still post to thingiverse in its occasional intervals of function.

It looks like https://wikifactory.com/ would like to become the next such site. Not sure how successful they are being so far.

Comment by Michael K Johnson — 2019 August 12 @ 09:47

• https://www.youmagine.com/ looks pretty active and is a lot more responsive than thingiverse. I might switch to publishing there, because thingiverse is just about pushing me over the edge… There’s also https://www.myminifactory.com/

I wish https://yeggi.com/ published an up-to-date list of sites they index, but perhaps they don’t want to directly enable search competitors. Still if you search for models there, those models will take you to various sites.

Comment by Michael K Johnson — 2019 August 26 @ 03:32

• Thanks, it is good to know about other sites for designs for 3D printing. The yeggi search engine might be useful, but only as useful as the tags people put on their models, which are very good. One of the hardest things for searching is guessing what tags people have used—because the models don’t have much text, automatic indexing is not very helpful, and tagging is essential.

Comment by gasstationwithoutpumps — 2019 August 26 @ 08:08

3. I’m not seeing much on wikifactory right now—they seem to be focussing more on web-based tools and collaborations than on being a repository of designs. (Searching “jewelry” gets 0 designs.)

I could use a source-code control system like git for my 3D-printing designs, but it seems like a lot of extra trouble when each design consists of just 3 files (an OpenSCAD file, the resulting STL file, and a photograph). It would provide off-site backup, though, which could be useful. I use Bitbucket and mercurial for larger projects (like PteroDAQ and my textbook), but even that seems like overkill for tiny projects.

Comment by gasstationwithoutpumps — 2019 August 12 @ 10:05

• Repositories are cheap, so a new repository for each project is reasonable, but also it’s possible to reasonably create a single repository and just commit new projects in subdirectories.

One of the things I’ve grown used to is putting everything in version control (rather than thinking of it as “source code control) — Git is at its heart a versioned filesystem. Mercurial has baked into it more assumptions about normal use for source code control. But either one of them is fundamentally a versioning system.

I typically commit changes early and often, especially for complex designs. It’s much better than “undo” in an editor because each commit carries semantics. It takes almost no time and is so easy to do that it only takes a few times of actually benefiting from the habit to outweigh the very small costs.

Thanks for sharing your experience on wikifactory. When Google+ went away, wikifactory offered to try to preserve some communities I was a part of, but their business plan wasn’t clear to us, and a lot of us had questions about jumping out of a frying pan into a fire, so a lot of those communities asked me to include them in the port I was doing to https://forum.makerforums.info instead of moving to wikifactory. That said, the concept of using the web to enhance collaborative design of physical objects is still attractive and I’m glad they are trying to do something useful there.

Comment by Michael K Johnson — 2019 August 12 @ 10:27

• I see that today, Atlassian sent out email that they are going to remove Mercurial support from bitbucket and transition to support only Git.

I was an early mercurial user — https://musings.danlj.org/2005/11/09/moving-to-mercurial.html shows when I started using it professionally — but have since become the friend referred to in the hovertext at https://xkcd.com/1597/ — at least metaphorically. ☺

Comment by Michael K Johnson — 2019 August 20 @ 16:47

• I got the notice from Atlassian also. I currently have 3 projects on BitBucket, but since they plan to support only Git and provide no way to transfer the Mercurial repositories to git, I can’t really see any reason to stay with BitBucket. Either I’ll be finding another provider that plans to continue to support Mercurial, or (more likely) I’ll move to github, which at least provides a way to import a Mercurial repository. (I don’t know whether that import includes the issue tracker and the wiki that BitBucket provides—an important consideration for the PteroDAQ repository.)

Comment by gasstationwithoutpumps — 2019 August 20 @ 17:11

• Both github and gitlab include wiki and issue tracking, but not sure about import from bitbucket wiki and bitbucket issue tracking. In both of their cases, they are well integrated into commits, so a commit message can say “fixes #1234” and issue 1234 will be closed when the commit is merged into master.

I use both github and gitlab, and have started to gravitate to gitlab because of their more flexible system for building websites attached to repositories; github is more constrained. I’ve been pretty happy with gitlab generally.

https://hg-git.github.io/ lets you keep using mercurial locally against a git repository remotely, but I quickly quit using it and just started using git for everything.

Comment by Michael K Johnson — 2019 August 20 @ 17:23

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