3.2 Position Information

The position information of a volume is handled by a routine, which writes the coordinates and the rotation matrix. The tree decoding routine transforms the coordinates and the rotation matrix of a volume to the global coordinate system, and then transfers the data to the routine which writes the translation and rotation of a volume into the SET format as follows:

@302,N1#301,M1,M2,M3,M4,M5,M6,M7,M8,M9,XC,YC,ZC
@100,N2,:9,'Name'#101,!N1(of the shape),!N1

Where

• @302 is the block number for geometric transformation;
  
• N1,N2 are the sequence numbers of each block;
  
• #301 is the sub-block number which defines the coefficients of the rotation-translation matrix;
  
• M1...M9 are the coefficients of the rotation matrix;
  
• XC,YC,ZC are the components of the translation vector;
  
• @100 is the block number which defines a constructed solid;
  
• :9 is the dictionary entry number for a name associated with the block;
  
• Name is the name of the volume;
  
• #101 is the sub-block number for transformation operation;
  
• !N1 is the reference to sequence number of the mother volume.
  

The geometric transformation is first defined with the given parameters and then the transformation operation is defined for a constructed solid. The principle of writing divisions into the SET format is equivalent to the case of normal volumes.