The following classes (.hh. icc and .cc) are related to the tessellated solid:

     G4PolyhedronArbitrary
     G4QuadrangularFacet
     G4TessellatedSolid
     G4TriangularFacet
     G4VFacet



How to contruct a G4TessellatedSolid

    G4TessellatedSolid is a special Geant4 Solid defined by a number of 
    G4VFacet.It is important that the supplied facets shall form a fully 
    enclose space which is the solid. 
    At the moment only two types of facet can be used for the construction of 
    a G4TessellatedSolid, i.e. the G4TriangularFacet and G4QuadrangularFacet.

    Example:
  
       .....
      First declare a tessellated solid 
           G4TessellatedSolid solidTarget = new G4TessellatedSolid("Solid_name");
      Define the facets which form the solid
 
           G4double targetSiz = 10*cm ;
           G4TriangularFacet *facet1 = new
           G4TriangularFacet (G4ThreeVector(-targetSize,-targetSize,        0.0),
                     G4ThreeVector(+targetSize,-targetSize,        0.0),
                     G4ThreeVector(        0.0,        0.0,+targetSize),
                     ABSOLUTE);
           G4TriangularFacet *facet2 = new
           G4TriangularFacet (G4ThreeVector(+targetSize,-targetSize,        0.0),
                                G4ThreeVector(+targetSize,+targetSize,        0.0),
                                G4ThreeVector(        0.0,        0.0,+targetSize),
                                ABSOLUTE);
           G4TriangularFacet *facet3 = new
           G4TriangularFacet (G4ThreeVector(+targetSize,+targetSize,        0.0),
                                G4ThreeVector(-targetSize,+targetSize,        0.0),
                                G4ThreeVector(        0.0,        0.0,+targetSize),
                                ABSOLUTE);
           G4TriangularFacet *facet4 = new
           G4TriangularFacet (G4ThreeVector(-targetSize,+targetSize,        0.0),
                                G4ThreeVector(-targetSize,-targetSize,        0.0),
                                G4ThreeVector(        0.0,        0.0,+targetSize),
                                ABSOLUTE);
           G4QuadrangularFacet *facet5 = new
           G4QuadrangularFacet (G4ThreeVector(-targetSize,-targetSize,        0.0),
                                G4ThreeVector(-targetSize,+targetSize,        0.0),
                                G4ThreeVector(+targetSize,+targetSize,        0.0),
                                G4ThreeVector(+targetSize,-targetSize,        0.0),
                                ABSOLUTE);
      Noew add the facets to the solid     
             solidTarget->AddFacet((G4VFacet*) facet1);
             solidTarget->AddFacet((G4VFacet*) facet2);
             solidTarget->AddFacet((G4VFacet*) facet3);
             solidTarget->AddFacet((G4VFacet*) facet4);
             solidTarget->AddFacet((G4VFacet*) facet5);
      Finally declare the solid is complete  
             solidTarget->SetSolidClosed(true);

  ...............

How to construct G4TriangularFacet:

    The G4TriangularFacet class is used for the contruction of G4TessellatedSolid.
    It is defined by three vertices, which shall be supplied 
    in anti-clockwise order looking from the outsider of the solid where 
    it belongs.Its constructor
   
      G4TriangularFacet (const G4ThreeVector Pt0, const G4ThreeVector vt1,
          const G4ThreeVector vt2, G4FacetVertexType);

    takes 4 parameters to define the three vertices:
          1) G4FacetvertexType = "ABSOLUTE": in this case Pt0, vt1 and vt2 are 
             the three vertices in anti-clockwise order looking from the outsider.
          2) G4FacetvertexType = "RELATIVE": in this case the first vertex is Pt0,
             the second vertex is Pt0+vt1 and the third vertex is Pt0+vt2, all  
             in anti-clockwise order when looking from the outsider.

How to construct G4QuadrangularFacet

    The G4QuadrangularFacet class is used for the contruction of G4TessellatedSolid.
    It is defined by four vertices, which shall be in the same plane and be supplied 
    in anti-clockwise order looking from the outsider of the solid where 
    it belongs. Its constructor
   
        G4QuadrangularFacet (const G4ThreeVector Pt0, const G4ThreeVector vt1,
            const G4ThreeVector vt2, const G4ThreeVector vt3, G4FacetVertexType);

    takes 5 parameters to define the four vertices
:
          1) G4FacetvertexType = "ABSOLUTE": in this case Pt0, vt1, vt2 and vt3 are 
             the four vertices required in anti-clockwise order when looking from 
             the outsider.
          2) G4FacetvertexType = "RELATIVE": in this case the first vertex is Pt0,
             the second vertex is Pt0+vt, the third vertex is Pt0+vt2 and 
             the fourth vertex is Pt0+vt3, in anti-clockwise order when looking 
             from the outsider.