Triangular Rhombic Torus

[gmtrcply]

I know this is not a "legal" Geomag build. Using larger balls is the only way to get the job done, because the sticks meet at such an acute angle.

A square or pentagonal outline is possible with the regular ½" balls.

The triangular build shown here uses 1" (25.4mm) balls. When using long Geomag sticks, 22mm balls are the lower limit.

[Eric]

Hey!
Nice to welcome a new poster
It's always a pleasure to see new constructions and new ideas.
Do you have more photos?

[gmtrcply]

Thanks for the warm welcome.

I did not take many individual photos. Here's a group shot of different orders. Higher orders are possible, no problem. By accident, I built the largest structure one order too big, so I had to remove one section. Because I did not have that many large steel balls of the same size, two different sizes were used.

( Edit 2024-10-04: Add parts count )
Order-0 would be (Edit) a Triangular Bipyramid (/edit).
Order-1: 36 Rods (Grey), 13 Spheres (1")
Order-2: 72 Rods, (Petrol), 24 Spheres (1")
Order-3: 108 Rods, (Fuchsia), 36 Spheres (22mm)
Order-4: 144 Rods, (Steel Blue), 48 Spheres (22mm)

[Eric]

Great work.
I'll have to try it with short rods.
I may have enough bigger spheres at the bottom of a drawer
I may even have enough long rods to try the big one.
Short rods are proportionally more powerful and allow you to create volumes with more parts and complexity, but the result is much more compact than with long rods.
Volumes achieved with long rods are always more slender and airy.

[gmtrcply]

Short rods are proportionally more powerful and allow you to create volumes with more parts and complexity, but the result is much more compact than with long rods.
Volumes achieved with long rods are always more slender and airy.

Yes, that sums up the dilemma of short vs. long rods. My initial dream was to build a Snub Dodecahedron with long rods. But after many collapses, I decided to be happy with a Snub Cube, and try other setups instead.

Also, I am torn between the compact "cute" look of builds with short rods, and the airyness of builds with long rods. For example, I have built a Snub Cube from short Chinese sticks and 11mm balls, getting it even more compact. But for inspecting the Geometry, the long rods offer a better view through the structure.

In spite of the high weight of the larger steel balls, the Triangular Rhombic Torus builds are very stable, due to the many triangles, and the high symmetry. They are best carried around by gently tilting them up by 90° at one corner, and then reaching underneath the bottom.

I only have limited amounts of short Geomag rods available, so I never tried this kind of build with these. I don't know what diameter might be the limit for these, but it should be similar as for the long ones.

Here are the details for the group shot:

1st order: Grey
· 13 Balls (1")
· 36 Geomag Sticks

2nd order: Petrol
· 24 Balls (1")
· 72 Geomag Sticks

3rd order: Fuchsia
· 36 Balls (22mm)
· 108 Geomag Sticks

4th order: Steel Blue
· 48 Balls (22mm)
· 144 Geomag Sticks

[Wagyx]

Welcome !
As a gift, here are the 3D models.

[gmtrcply]

(...) here are the 3D models.

Thanks. This is the first time that I come across these file fomats. After searching for online viewers, I realized that Windows has built-in tools as well.

[gmtrcply]

I'll have to try it with short rods.
I may have enough bigger spheres at the bottom of a drawer

I have created Order-1 and Order-2 with Chinese short rods and 21mm spheres, and it worked fine. Maybe I'll try Order-3, but I have to disassemble Order-2 first. Currently, I only have 50 spheres of this odd size.
With 27mm Geomag rods, 22mm should be enough, as these have slightly more diameter. But the magnets should be strong enough for using much larger diameters.

( Edit 2024-10-04 ) I quickly built Order-1 versions with 27mm Geomag rods. 21mm spheres can be used, but it's a bit tight, so 22mm is the best diameter for these. With increasing sphere diameter, the gap between the spheres in the middle layer gets smaller. With 35mm spheres, the gap is down to about 1mm. (/Edit) ( Edit 2024-10-06 ) A 40mm sphere size is definitely too large. An Order-1 structure can be assembled, but you can see that the middle layer triangle bulges outwards, and there is a gap of about 2mm at one point. (/Edit)

[gmtrcply]

Here is a comparison of different Sphere sizes for the Torus build.



The large structure in the background is built using 58mm rods, and solid 50mm 100Cr6 spheres. Regarding the Sphere size with Geomag Rods, things start getting complicated with diameters of more than 40mm. The 45mm 100Cr6 have a weight of 372g, the 50mm 100Cr6 have a weight of 511g (per sphere, no kidding). The weight can be calculated easily, 100Cr6 has a density of about 7.81.

The stats:

• Steel Blue: 58mm Geomag Rods, 50mm Spheres, about 7kg total weight.
• Yellow: 27mm Geomag Rods, 21mm Spheres, total weight: 660g.
• Red: 27mm Geomag Rods, 28mm Spheres, total weight: 1335g.
• Blue: 27mm Geomag Rods, 35mm Spheres, total weight: 2443g

The structure built with 21mm spheres is solid, but the rod end touch. With 40mm, the structure shows gaps. Therefore, I would recommend a sphere diameter range from 22-35mm for the 27mm rods.

[Eric]

First time I see geomag structures with spheres that big!
Well done!
The big one looks like the Atomium
Unbelievable it doesn't collapse without geomag pro-L.