## File .brp

Definition of a geometric model of type Boundary Representation.

A face is defined by some contours. The first contour is the extern contour, which must be always included; the other contours describe the holes in the face.

A contour of a face is defined by the values of vertex indexes which limit it.

You must verificate the condition that all vertices of all contours in a face are complanar.

filebrp = { . pbrep . section_vertex . section_face . } . dot

section_vertex = { . vertices . defvertex . }

section_face = { . faces . defface . }

defvertex = number_vertex . { vertex }

number_vertex = number_integer

vertex = number_real . number_real . number_real

defface = number_face . { defcontour }

defcontour = { . number_contour . { . contour . } . }

contour = number_index . { index }

number_index = number_integer

index = number_integer

filebrp

definition of file .brp.

section_vertex

definition of all vertex. All the vertex are definited by a sequence of vertex definition. It is possible to associate an index to every vertex, 0 to the first, 1 to the next and so on.

defvertex

definition of the verteces.

number_vertex

definition of the number of the verteces in a brep model.

vertex

definition of a single vertex. A vertex is a point in the space.

sections_face

definition of all faces.

defface

definition of the faces.

defcontour

definition of the contours in a face.

contour

definition of a contour.

number_index

number of verteces in a contour.

index

index of a vertex of a contour.

Example of file .brp:

{ pbrep

vertices

10

16 0 54

16 10 54

8 16 54

0 10 54

0 0 54

16 0 30

16 10 30

8 16 30

0 10 30

0 0 30

faces

7

{ 1

{ 5 0 1 2 3 4 }

}

{ 1

{ 4 1 2 7 6 }

}

{ 1

{ 4 2 3 8 7 }

}

{ 1

{ 4 3 4 9 8 }

}

{ 1

{ 4 4 0 5 9 }

}

{ 1

{ 4 1 0 5 6 }

}

{ 1

{ 5 5 6 7 8 9 }

}

}