Thanks. I feel I should always point out that this is copied from a piece by Nat Friedman which is discussed in the discussion linked to in my original post!
It is nice to be able to pick up the item from the base and hold it.
This is another similar shape that I like.
1 Like
Very nice.
Here’s a piece I made myself recently. So far only as rendering and a small 3d print, but I would love to see it larger scale one day. It uses the Bryant-Kusner parametrization of Boy’s surface, but with a different projection than the usual closed one, and openings cut to avoid the self-intersections (and the arrangement of these openings was inspired by a hand drawn illustration in George Francis’ A Topological Picturebook).
10 Likes
Also - that Charles Perry sculpture actually looks very close to something else I was looking at recently - related to a way of making a Sudanese Moebius band by sweeping a helix through a stereographically projected 4d rotation. Using a straight line instead of a helix gives you a zero thickness non orientable surface, but the nice thing about using a helix is that you can do the double cover and get a closed manifold solid in one go without having to offset.
The sweep creates a shape that goes to an infinite plane, and you can trim this to get a shape like the Charles Perry sculpture you linked, or you can perform another 4d rotation to close this up and get the Sudanese Moebius with a circular end/
SudaneseMoebiusSolid2.gh (14.1 KB)
SudaneseMoebiusSolid_Perry.gh (12.1 KB)
4 Likes
I really like that! Very hard to make using subtractive manufacturing methods but I bet the 3d printed version is nice. What 3d print technology and materials did you use?
1 Like
that looks like an Oloid, at least the lower image reminds me of it. something which is actually very simple to produce in rhino, two circles lofted into each other. i was actually trying to find a way to introduce a third circle for the initial example in this topic, but that did not work out at all.
1 Like
An oloid is a quite different shape to the above. Try spinning this around:
SudaneseMoebius.3dm (337.5 KB)
1 Like
Nothing fancy yet, just white nylon SLS
Yes, I imagine if trying to CNC mill a shape like this it would be rather challenging to get into those folds.
I guess pieces like the Michael Foster ones you linked above involve a lot of skilful and patient chisel work!
1 Like
Is there a split plane or surface that would divide it into 2 parts that could be machined from both sides on a 3 axis CNC? Is there a mathematical way of defining a splitting plane or surface? This can be quite an art when creating moulds but since the shape is so mathematical, can the split plane / surface be calculated so it splits the part so as to not leave any overhang on either side of either part?
I can’t open it to try 
Here is the link to watch the video how it was made
2 Likes
Wow! Amazing to see it done by hand! I CNC machined mine from each side which still left a lot of sanding to do to get the shape smooth in the steep part of the twist. To carve the whole thing by hand takes a lot of skill and a lot of patience!
This makes me appreciate the original piece by Nat Friedman (RIP) even more…
Carved from granite!
This also makes me realise something about the design of the shape… I had tried to keep an oval profile like you turned on your lathe before carving but I couldn’t get the surface to bulge out in that area whilst blending to a minimal surface through the twist in the centre…
I think the only way to get that is by hand carving and blending between a surface that bulges out in the areas circled in red and the minimal surface that goes through the centre of the twist.
That is perhaps how to tell between a CNC machined one that is driven from CAD and a hand carved one done by the method you show in your video!
Anyway… it looks great! What material will you use next?
1 Like
“What material will you use next?” Hahaha, I donno. I just accept the challenge, do it and move onto another one. This was my first time curving wood and acrylic to be honest with you. I also cut glass bottles into spiral shapes. Have you seen those videos? I think you will also love those even more if you liked this one.
Anyway, I don’t mind sharing my model with you if you think you need it for your CNC machine. I know you did your hard work trying to figure it out - I couldn’t, so I just made the model in Rhino ( Believe me it wasn’t easy)
Just go to the link I sent you and you will have access to the channel. Watch the glass bottles and tell me if it can be done in grasshopper
Cheers
I did it in Grasshopper eventually so I have the model and I can scale it for different sized blocks of wood but each time I go back to the model there seems to be something wrong with it and it takes me a day to remember how I did it and get it working again!
I want to make one from Linden wood (or Lime wood) because it is apparently very nice to carve and I want to make one in a very white, straight grained timber so I can stain one half black. Have you ever carved Linden wood?
https://whitmores.co.uk/product-category/woodcarving-supplies/european-lime-carving-blanks/
And yes! your bottle spiral cutting is brilliant!
Hi Marty
Sorry I didn’t reply any earlier. We are in the business of retail stores and furniture making. What we use “mostly” is poplar, pine, oak and walnut. The first two are used for structure. This was the first time I heard of linden wood, maybe because it is not popular in Canada. I searched in Google and found out that it is a soft wood for carving. That would be a great choice for your CNC machine and also for it’s grain pattern. Send me a photo once you finish doing one I would love to see it. I don’t know about painting one side black though. Personally I prefer one single finish because it will make balanced tone and shadows on both sides and easier to look at. I wished I could have a CNC machine but I have a hard time to choose one for my home. There is one called “Snapmaker” which has 3 operation all in one machine (3D printing, laser engraving, and CNC carving). Do you know any CNC brand that you prefer the most?
Cheers
Thanks !!!
So nice
1 Like
I made my CNC using aluminium extrude sections and standard stepper motors and drivers commonly sold online.
There are so many CNC machines available now it’s hard to recommend one. If you are only ever going to cut wood on it then something like the Snapmaker would be great but they are quite small I believe. I made mine big enough to cut an 8’ x 4’ sheet of plywood because it’s great for cutting profiles from sheet plywood, MDF etc.
I seem to get bombarded with adverts for Chinese machines that look pretty good. The question I’d be asking is how hard is it to get spare parts in the country you live in. Unless you want a serious production throughput with well supported reliability then you don’t need an expensive machine.
If cut a lot of sheet material then go for a 8x4ft machine and add tool changer and vacuum table if you want the expense and convenience.
If you just want to 3d carve small objects then the Snapmaker will be great.
1 Like
Much appreciated for your reply. Wow, you made your own? What are you an engineer? 
I don’t need it for business just for my own hobbies. We have all kinds of CNC machines where I work (Flat, 3 and 5 axis). I picked Snapmaker just because it does 3 things in 1.
Anyway, thanks again for your reply. 
Fred
I am an engineer but building a CNC is easier than you think.
I did buy a homemade one first which helped me understand how they work and then I designed one in Rhino using off-the-shelf parts. I think the popularity of 3d printers really helped make motion control projects more accessible to people.
I like the idea of the 3in1 Snapmaker as long as it is good at doing all 3 tasks.
My experience of a cheap 3d printer kit was that it was a fantastic learning experience and it teaches you to design to the capability of the machine but it could be so frustrating trying to get a print to work. I would hate to have a 3in1 machine where all 3 functions were a bit unreliable! That’s ok for a hobby but no good if you need to rely on it.
My CNC is better than a hobby machine but if I have to cut £150 per sheet material I get nervous in case something goes wrong!
You will learn loads from a Snapmaker though. I’m sure you would find creative ways to get the most out of one!
Thanks Marty. I ordered one and it will be shipped to me in about a month 
Well, nothing else I can do but wait. Will let you know how good it is. I am sure I will have a ton of things to learn.
Cheers