Definition of TGC

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2011-07-15
2013-04-22
  • Norbert Braun
    Norbert Braun
    2011-07-15

    Hi all,
    does anyone know the definition of the TGC (truncated general cone) primitive? Vertex and height vector are clear to me, but I have no idea what A,B,c and d are. A quick Google search turned up nothing helpful.

    Thanks in advance!
    Best regards, Norbert

     
  • Sean Morrison
    Sean Morrison
    2011-07-15

    The appendix of the MGED tutorial series ( see http://brlcad.org/wiki/Documentation ) lists all of the primitives and their parameters with diagrams of what each value represents.  For the TGC, it's a fully generalized cylinder so A and B are vectors for one of the cylinder caps that describe an ellipse.  The ellipse on the opposite end doesn't need to be the same size, but must match the same shape so c and d are merely vector scaling factors.  Example:

    V 0 0 0
    h 0 0 1
    A 1 0 0
    B 0 1 0
    c 1
    d 1

    Something like that.

    Cheers!
    Sean