NetLib Polyhedra DataBase

    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.

    Virtual Polyhedra, (c) 1996,George W. Hart