I converted most of the VRML Johnson solids here from the NetLib database
of polyhedra compiled by Andrew Hume. It is a useful database, and most
of the files are in good shape, but as a caution to others who might wish
to use it, I must mention that I ran across just a few omissions and errors
in a couple of the files. I corrected these in producing the VRML files
in the main body of this work:
- There is no ":solid" data field in files number 9-21 and
32. So these files do not contain the data necessary to construct a solid
figure. This includes all the Archimedean semi-regular solids.
- There are six to ten triangular faces missing in each of files 66-69.
- File 70 has a couple of faces and vertices incorrectly placed.
- The solid in file 81 is a rhombicuboctahedron, without the crucial
twist of one cap necessary to make a elongated square gyrobicupola.
- In file 108, one face is misaligned, and the three-triangle point is
missing from the end. Three of the defined triangles are actually identical.
- And, file 115 has one of its three augmentations in the incorrect place.
Two cupolas are are adjacent, and where they meet the solid is not convex.
I have not been able to get in contact with the author about updating
the files.
The erroneous objects, as I found them:
- File 66. gyroelongated
triangular cupola (J22)
- File 67. gyroelongated
square cupola (J23)
- File 68. gyroelongated
pentagonal cupola (J24)
- File 69. gyroelongated
pentagonal rotunda (J25)
- File 70. gyrobifastigium
(J26)
- File 81. elongated
square gyrobicupola (J37)
- File 108. augmented
tridiminished icosahedron (J64)
- File 115. triaugmented
truncated dodecahedron (J71)
Correct VRML versions of these polyhedra are included with my Johnson
Solids. Versions of the original NetLib-format data files which I have
corrected are also available here for anyone else who may want to use them
as input to any software designed for the NetLib format: 66,
67, 68, 69,
70, 81, 108,
115. I only examined and changed the solid
and vertex fields; I don't know if there are problems with any other
fields.
Note that this is not meant as criticism. If anything this should emphasize
the difficulty of the task, and the work that went into making all the
correct files.