IndexedFaceSet { 
  eventIn       MFInt32 set_colorIndex
  eventIn       MFInt32 set_coordIndex
  eventIn       MFInt32 set_normalIndex
  eventIn       MFInt32 set_texCoordIndex
  exposedField  SFNode  color             NULL
  exposedField  SFNode  coord             NULL
  exposedField  SFNode  normal            NULL
  exposedField  SFNode  texCoord          NULL
  field         SFBool  ccw               TRUE
  field         MFInt32 colorIndex        []        # [-1, )
  field         SFBool  colorPerVertex    TRUE
  field         SFBool  convex            TRUE
  field         MFInt32 coordIndex        []        # [-1,
)
  field         SFBool  colorPerVertex    TRUE
  field         SFBool  convex            TRUE
  field         MFInt32 coordIndex        []        # [-1, )
  field         SFFloat creaseAngle       0         # [0,
)
  field         SFFloat creaseAngle       0         # [0, )
  field         MFInt32 normalIndex       []        # [-1,
)
  field         MFInt32 normalIndex       []        # [-1, )
  field         SFBool  normalPerVertex   TRUE
  field         SFBool  solid             TRUE
  field         MFInt32 texCoordIndex     []        # [-1,
)
  field         SFBool  normalPerVertex   TRUE
  field         SFBool  solid             TRUE
  field         MFInt32 texCoordIndex     []        # [-1, )
}
)
}
自由曲面を書くいわゆるポリゴンをあらわすノードです。
面への色のつけ方ですが、
#VRML V2.0 utf8
Shape {
  geometry IndexedFaceSet {
    coord Coordinate {
      point [0 .2 1, 1 0 0, 0 1 0, -1 0 0 ]
    }
    color Color {
      color [1 0 0, 0 1 0, 0 0 1]
    }
    coordIndex [
     0 1 2 -1
     3 1 2 -1
     0 3 2 -1
     0 1 3 -1
    ]
    colorIndex [0 1 2 -1 0 1 2 -1 0 0 0 -1 0 1 2 -1 ]
    solid FALSE
  }
}