ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
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FEM software (FLAC-3D) and two typical 2D FEM software 
(FLAC-2D, RFPA) are selected for example study now in 
CUMTB. With the transferring module the space division 
information and rock features contained in the output file of 
LYNX could be used for the data source of FLAC and RFPA at 
present time. 
The typical 2D profile and 3D space division of LYNX are shown 
in figure 3 and figure 4. Figure 5 shows a case model of RFPA 
for tunnel engineering influence analysis. 
Fig.3 2D profile model of LYNX 
Fig.4 3D space division of LYNX 
Fig.5 Tunnel engineering of RFPA 
4 DATA STRUCTURE COMPARISON BETWEEN 3DGM and 
FEM 
Generally, the data files of 3DGM and FEM for space division 
and attribute description are comprised of three parts: user 
identification information, coordinate information and attribute 
information. 
4.1 The files format of microLYNX 
The 2D profile data of microLYNX are stored in ".Per files. It 
records the geometry information of the polygons of geological 
body in binary system, and could be transferred into *.Txt files. 
The data of points could be obtained from the *.Txt file, and the 
information include: 
Point number, 
x, y, z, 
user ID for polygon, 
and point type. 
The 3D raster data of microLYNX are stored in *.Mdb files in 
Access. This File contains both tables for grid definition and 
grid-body element definition. The grid definition table contains 
the identifing code and type of the model, the size definition of 
the body element, the origin of the local coordination system, 
and the numbers of body elements along each axis. The 
gird-body element definition table contains row number, column 
number, layer number, element attributes, etc. 
4.2 The file format of FLAC 
The FLAC-3D applies cubic, rectangles and TEN for the space 
division, and the raster data are stored in *.DAT files. The file is 
comprised of two parts: geo-boundary and grid definition, 
mechanical parameter definition. 
For example, the geo-boundary definition of a case is as: attach 
face range x=0, 400 y^0,250 z^8.5, 9.5. 
The grid definition for the model’s size and elements numbers 
along each axis are as following: 
gen zone brick size 40 25 1 P0 0, 0, 0 P1 400, 0, 0 P2 
0,250,0 P3 0,0,9. 
And, the mechanical parameters definition of a case is as 
following: 
ini d 2.76e' 3 range x=0,400 y=0,250 .2=0,9 prop bulk 
9.9e 3 cohesion 2.8 shear 7e 3 friction 3.6e’ tension 2.9 
dilation 1.1e 1 . 
The FLAC-2D chiefly applies rectangles for the grid division. Its 
file is comprised of the grid definition and the boundary 
definition. 
For example, the definition of rectangle grids is as: 
grid 400, 240; mode e; 
gen -64, -24 -64,24 -56 24 -8, -24 M, 101 j= 
1,241