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Post by displaser on Sept 30, 2022 15:49:48 GMT -7
My thanks to everyone that is working on these 3D printed items. What a great project! Many thanks for sharing these files.
This will be a perfect reason for me to unbox my printer and work towards building one of these as the ultimate goal!
Great work!
Thanks, Greg
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Post by Ron Walker on Sept 30, 2022 17:27:43 GMT -7
There is an incredibly impressive 3D model of a Zeiss projector on a website called digitalcentrality. Sadly it looks like the owner is reluctant to share the file (I may be wrong). In any case, I was inspired to start learning 3D CAD to make planetarium related components and perhaps a model or two too. After messing around with Tinkercad which is a great introductory tool (but really limited) someone recommended Autodesk Fusion 360. Amateurs can download free license/copy for Fusion 360 for non-commercial projects - I think it is limited to 10 editable projects at a time. The package is incredibly powerful and is a real professional level product. With that comes a very steep learning curve. There are plenty of youtube tutorials but I am old fashioned enough to have bought an introductory book. I will freely admit that I am at the very slow clunky clumsy stage of using it. Perseverance is a pre-requisite but as with all computer packages the basics functions are not too difficult to learn but the refinements take weeks to get to grips with. Playing with it seems to be the way to learn. I attach a screenshot of my first attempts at the beginnings of a projector model - it is clunky and not accurate but it will gradually get there. When it is in a more advanced state I will share the printable file with folks here. As with all my projects you really should not expect speed! View AttachmentThat is the one I remember: www.digitalcentrality.com/Planetarium/
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Post by Ron Walker on Oct 3, 2022 11:08:02 GMT -7
So after about 5 months the model is not quite finished but is at a reasonable state to share - photos and a link the model files will follow below. It is not perfect- I have not finished the meridian projector globes that sit on the frame and I am noticing ever more imperfections that should have been a little better. Please remember this is my first real foray into 3D modelling. First pictures are of the build - most of the photos are in black and white because they look better and because so many of the source photos that I have been staring at for weeks are black and white it just feels right. View Attachmenthalf made: View AttachmentI see a Spitz Jr. lurking in the back.
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Post by Ron Walker on Oct 3, 2022 11:14:20 GMT -7
The more I look at this, the more excited I become. Imagine a gift of this where all of the projectors are adjusted to the date of the recipients birthday. How few would get it, but how special that would be.
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Post by scotttucker on Oct 13, 2022 4:44:11 GMT -7
Minor update - I have added two files to the Zeiss transfer folder - meridian projector and meridian support- for the two spherical projectors that sit low down on the lattice legs (photo to follow).
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Post by scotttucker on Oct 13, 2022 4:48:36 GMT -7
My thanks to everyone that is working on these 3D printed items. What a great project! Many thanks for sharing these files. This will be a perfect reason for me to unbox my printer and work towards building one of these as the ultimate goal! Great work! Thanks, Greg You are welcome - I printed mine in black, but am beginning to wonder whether it would have been more effective to print in matt grey/ white and then paint it - do you have a plan? Post piccys - especially if you improve it (or add lights!)
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Post by Ron Walker on Oct 13, 2022 11:45:10 GMT -7
r you saying print in matt gray so you can paint it matt black and not shiny black?
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Post by scotttucker on Oct 13, 2022 12:47:15 GMT -7
r you saying print in matt gray so you can paint it matt black and not shiny black? When you put it like that it does sound slightly mad! . I didn't really explain my fairly poorly thought-out approach on that front. I think a matt finish looks better because the imperfections and layers don't quite catch the light as much as gloss. Originally I started printing with matt black filament (Tinmorry brand) but it kept clogging up the printer nozzle no matter what I did. In the end I threw most of the reel away. A cheap matt grey filament seemed to work much better but I went for black in the end with the intention of not painting it. I guess with the right primer you could paint any substrate with any finish.
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Post by Ron Walker on Oct 13, 2022 21:12:25 GMT -7
I will try and send pictures tomorrow but I just had to say I tried my first printout today. It is of the central core that contains the set of 33 or so sliprings for latitude movement. It came out far from perfect and with no flat side to build upon but I just had to comment on the exceptional attention to detail. One can see each of the slip rings all the way around as well as the sliders ( some of which printed correctly). Just great work Scott. Now I really want it bigger but that is just me being a pig.
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Post by scotttucker on Oct 15, 2022 2:33:02 GMT -7
Yeah- the underside of that component did not print particularly well for me either- the upper side did. You could always split the component in half and glue together. I just opted for tidying up the lower half with a soldering iron on the lowest heat. I also got a lot of stringing on the underside of the lattice legs and the planet cage struts too.
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Post by scotttucker on Oct 19, 2022 12:32:51 GMT -7
Probably the hardest part in the modelling was getting the starplates distributed properly around the star globe. I have been looking at ways of doing it more easily (perhaps because I want to model different projectors). There are a couple of 'how to make a truncated icosahedron' tutorials on you tube for Fusion 360. There is a simple method using the 'circular pattern' method but then I found this method which was a little harder to follow but has one huge advantage. The advantage comes at the point at about 5mins 11 when you make a plane 2/3 up from the centre of the solid shape. What if, instead of following the video to the letter, you change the distance? In fact, if you change the to 0.6285 times the length, rather than 2/3 times the length you end up with an isodistant truncated icosahedron. Thanks go to Dr Peter Huybers on his paper searching for the roundest soccer ball (if you remember that one from the old OC thread on starplates!) which gave the solution for making the isodistant form.
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Post by scotttucker on Oct 19, 2022 12:50:00 GMT -7
These two Fusion 360 models illustrate the importance of the isodistant form compared to the normal truncated icosahedron: In the isodistant form on the right the pentagons and wonky hexagons (or more accurately ditrigons) are a similar size whereas in the normal soccer ball, the pentagons are smaller than the hexagons. The holes in these models are created by cutting the faces with a sphere and show clearly how the pentagon faces of the 'normal soccer ball' sit at different distances from the centre (than the hexagon faces (the holes are smaller in the pentagons than hexagons on the 'normal' version. In contrast, all faces on the isodistant form are at exactly the same distance from the centre (hence the name). It is not that big a deal but the practical upshot is that the isodistant form makes it easier to align starplates uniformly onto the surface of a sphere when using Fusion 360 which is surprisingly difficult. I guess that is a technicality that won't be of much interest to most people but it might be quite useful for people modelling starballs from scratch.
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Post by Ron Walker on Oct 19, 2022 19:20:45 GMT -7
The fog is entering my brain now. Do you remember under what title those posts were?
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Post by scotttucker on Oct 20, 2022 11:01:39 GMT -7
Hi Ron,
The old thread was: Observatory Central _ Home Built Optical Planetariums _ Optical star ball projector based on a truncated icosahedron
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Post by Ron Walker on Oct 21, 2022 11:13:07 GMT -7
Thanks Scott: It is rebuilt, just need to add the pictures.
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