is S3 as shown in Stage 2 of the figure. In this fashion, all the surfaces intercepted are traversed and at the end of Stage 4 the final bin contains the information about which surface encloses which surface(s). Now, if the final bin is emptied (which is also a LIFO bin), it shows the following hierarchy of the enclosing surfaces: S1 > S2 > fS3 [S4g: ð2Þ That means S1 encloses S2 which in turn encloses S3 and S4. It may be noted that different traversing paths will produce different sets of hierarchies of the enclosing surfaces. Different serial numbers of different walls in the matrix [GeoMat], correspond to these surfaces of the present domain of Fig. 3. In a similar manner, the breadth of the muffler domain, which is nothing but the set of all the rows of the mapped matrix, is traversed starting from the leftmost end of the muffler which corresponds to the first column of the matrix. For each column of the matrix (except for some, that correspond to vertical
Fig. 4. Last-in-first-out (LIFO) based bin system to keep track of the volume enclosures.