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cell-first projection of the 16-cell

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hbghlyj Posted at 2024-11-12 20:16:57 |Read mode
Cell-first Projection
The cell-first projection of the 16-cell has a cubical envelope. This projection is interesting in that all the edges of the 16-cell project onto the edges of the cube and the diagonals on the faces of the cube, forming a wireframe of the cube with each face crossed. It corresponds with the two possible ways to inscribe a tetrahedron inside a cube such that the edges of the tetrahedron lie on the faces of the cube.
MW97WX9BDJWJGWDJH8Q0GAQSJ0[1].png
The blue edges outline the cell closest to the viewer. Between this cell and the cubical envelope are 4 tetrahedral volumes that correspond with the 4 cells surrounding this blue cell. There are 6 cells that project onto the 6 faces of the cubical envelope (not shown here because they are being viewed edge-on). These 6 cells connect with the other side of the 16-cell, which contains the remaining 5 cells in a dual arrangement to the cells seen here. The following figure shows this opposite cell:
Q19XPPGQHENMJBRG1A96AGME22[1].png

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 Author| hbghlyj Posted at 2024-11-12 20:17:19

下面是我编写的可视化此投影的Mathematica代码

Last edited by hbghlyj at 2024-11-12 20:34:00
  1. Manipulate[ConvexHullMesh[Drop[RotationMatrix[{{1,1,1,1},{0,0,0,1}}].#[[1,1]],-1]&/@Table[RegionIntersection[Line[i],Hyperplane[{1,1,1,1},d]],{i,Tuples[{IdentityMatrix[4],-IdentityMatrix[4]}]}]],{d,-1,1}]
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anim.gif
  1. Export["anim.gif",Table[Graphics3D[{Opacity[.7],GraphicsComplex[{{0,0,t},{0,t,0},{t,0,0},{1-t,1,0},{1,1-t,0},{1,1,t},{1,0,1-t},{1-t,0,1},{1,t,1},{t,1,1},{0,1,1-t},{0,1-t,1}},Polygon[{{1,2,3},{4,5,6},{7,8,9},{10,11,12},{1,2,11,12},{1,3,7,8},{2,3,5,4},{5,6,9,7},{4,6,10,11},{8,9,10,12},{1,8,12},{2,4,11},{6,9,10},{3,5,7}}]]}],{t,0,1,0.05}],"DisplayDurations"->0.2]
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 Author| hbghlyj Posted at 2024-11-12 20:24:11
如何对更复杂的四维多胞形(如 24 胞、120 胞、600 胞)进行相同的投影可视化?

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