[ To Do: More documentation and material planned.]
The rule system alternates between the two tetrahedral 2x2x2 rules, with a terminating symbol off the tetrahedra:

All of the orthogonal (face-on) projections are filled with no occlusion; the number of elements matches the 2-D dimension product (2^ng x 2^ng) and the coordinate triplets cover all unique coordinate pairs. Are there other sets that have this property?
The pi/4 rotated projections are transparent, a fractal curve with a dimension between one and two that bounds a single fractal prototile.
[ To Do: Compare this with the Serpinski sponge, 2 symbol with no alternation. ]

The fifth generation (32 x 32 x 32), rendered with darker shades at increasing depth.
(stereo pair, cross view)
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Larger versions
(stereo pair, cross view)
The seventh generation (128 x 128 x 128), rendered with darker shades at increasing depth.
Large version
Rendered animated rotation of the system's fifth generation cube, between adjacent faces of of the volumetric cube. A larger animation of the system's seventh generation.
Same 2-D + time animation as above, but skewed in space-time (Euler angles pi/6 radians).
A 2-D slice orthogonal to one of the three long diagonals. There are three scaled (x1/2) copies of the whole, two at top and one at bottom. The 3-D pattern itself has four scaled (x1/2) copies of the whole, at each corner of a tetrahedron. |
The orthogonal projection along any of the twelve short diagonals. This has the same symmetries as the slice at left, but is forshortened vertically by a factor of 1/sqrt(2). |
The second generation, oversampled by x3 and sliced and volume rendered along the long diagonal. The apparent layering is due to flaws in the Space Software rendering engine with small volumes (243 voxels in this case). An MP4 format movie of this figure: Altered_tetrahedron_sliced.mp4.
Matlab command:
>> volOut = L_System_3D_tiling( '', [ng], 3, 1, 0, '', 1, [0 0; 0 0], [0 0; 0 0], [0 2; 2 0], [2 0; 0 2], [1 0; 0 1], [0 1; 1 0] );
where [ng] is the number of generations.
The raw seventh generation volume: LS-2x2x2_3s-0_2000_2280-7g.vol.gz. Oversampled and rendered with Space Software.

Maximum intensity projection (MIP) of the seventh generation rendered in the long diagonal direction:
Large version
This projection forms a motif for a rectangular tiling with a single fractal prototile.
Matlab command:
>> volOut = L_System_3D_tiling( '', [ng], 3, 1, 0, '', 1, [0 0; 0 0], [0 0; 0 0], [0 2; 2 2], [2 2; 2 2], [1 1; 1 1], [1 1; 1 0] );
where [ng] is the number of generations.
The raw seventh generation volume: LS-2x2x2_3s-0_2186_3279-7g.vol.gz is attached below. Oversampled and rendered with Space Software.
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Terms for use: There are no restrictions on the use of these images. Claiming to be the originator or owner, explicitly or implicitly, is bad karma. A link (if appropriate), a note to dow[at]uoregon.edu, and credit are appreciated but not required.
| Attachment | Size |
|---|---|
| LS-2x2x2_3s-0_2000_2280-7g.vol.gz | 19.03 KB |
| LS-2x2x2_3s-0_2186_3279-7g.vol.gz | 32.96 KB |
| Altered_tetrahedron_sliced.mp4 | 776.02 KB |
Comments
mp4 file format attach
Hey Peter, I'm trying to attach a .mp4 video, and I added this extension at admin|settings|file attach, and it appears on that list when I go back to it. Is there another equivalent list, or am I not actually changing the proper list?
"The selected file Altered_tetrahedron_sliced.mp4 can not be attached to this post, because it is only possible to attach files with the following extensions: jpg jpeg gif png txt html doc xls pdf ppt pps odt ods odp tif tiff zip gz m cpp h vol.gz vol"
animations; mp4s
Wow some really interesting animations Mark! Very impressive. Youre going to inspire me to dig into my badly neglected math-art projects if you keep this up. I've still got music on the brain for the time being. Looking the larger versions of your 3d L-systems almost made my heart skip a beat. Are these going to bifurcate and scale at some point ie make them into binary-tree like structures with increasingly smaller representations at the ends of the branches...?
So I think I fixed the mp4 attachments. Glad to see you tried to play with admin settings. Couple things: I think that in that long list of extensions they don't want any '.' [period] before the extension. Also on the page where these are set administer->settings->file uploads there are multiple user profiles each with its own set of attachments so I usually add all attachment types to all the different user profiles. Anywho, I made a mp4 text file and it seemed to attach ok so I think its working.
mp4 attach
D'Oh! I should have caught the period error, thanks.
"...binary-tree like structures..." Yes, triplets of little tetrahedrons on tetrahedron corners, ad infinitum.
Sometime I'd like some short music riffs on videos like these, themes that repeat well over their short (4-30s) time frames. Your "percussive guitar" riffs and loops might be good for this. By the way, I loved the cover clips you posted, particularly 'fat bottomed girls'. The self harmony was good.
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