Encyclopaedia Index

FACETDAT

FACETDAT is the name of the file in which the PHOENICS SATELLITE, when it detects the presence of 'VR objects' (i.e. those which have their shapes described by way of facets) writes data which are to be read by, and acted upon, by the PHOENICS EARTH module.

The FACETDAT file contains information about every VR object which is to be considered in the calculation, deriving it directly or indirectly from what is in the Q1 file.

For example, the Q1 for library case 360 contains the lines:


> OBJ,    NAME,        RELIEF
> OBJ,    POSITION,    0.000000E+00, 0.000000E+00, 0.000000E+00
> OBJ,    SIZE,        2.000000E-01, 2.000000E-01, 1.000000E-01
> OBJ,    GEOMETRY,    cubet
> OBJ,    ROTATION24,        1
> OBJ,    TYPE,        PRESSURE_RELIEF
> OBJ,    PRES_RELIEF,   1.000000E+03, 0.000000E+00

> OBJ,    NAME,        SPHERE1
> OBJ,    POSITION,    0.000000E+00, 0.000000E+00, 0.000000E+00
> OBJ,    SIZE,        1.000000E+00, 1.000000E+00, 1.000000E-01
> OBJ,    GEOMETRY,    cylinder
> OBJ,    ROTATION24,        1
> OBJ,    GRID,              2
> OBJ,    TYPE,        BLOCKAGE
> OBJ,    MATERIAL,       -1
> OBJ,    TIME_LIMITS,   ALWAYS_ACTIVE
> OBJ,    INI_PRESS,     0.000000E+00
> OBJ,    SCAL_FIXF,     0.000000E+00

and the corresponding FACETDAT starts as follows:

OBJECT=     1  NFACETS=     6  OBJNAM = RELIEF   IOBJTYP =      7  OBJCLASS = VOL-OBJECT
BOUNDING BOX= 0.000000E+00 2.000000E-01 0.000000E+00 2.000000E-01 0.000000E+00 1.000000E-01
* clip art rot=   1 a,b,g  0.000000E+00 0.000000E+00 0.000000E+00
 2.000000E-01 2.000000E-01 0.000000E+00 0.000000E+00 2.000000E-01 0.000000E+00
 0.000000E+00 2.000000E-01 1.000000E-01 2.000000E-01 2.000000E-01 1.000000E-01
 2.000000E-01 0.000000E+00 0.000000E+00 2.000000E-01 2.000000E-01 0.000000E+00
 2.000000E-01 2.000000E-01 1.000000E-01 2.000000E-01 0.000000E+00 1.000000E-01
 0.000000E+00 0.000000E+00 0.000000E+00 2.000000E-01 0.000000E+00 0.000000E+00
 2.000000E-01 0.000000E+00 1.000000E-01 0.000000E+00 0.000000E+00 1.000000E-01
 0.000000E+00 2.000000E-01 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00
 0.000000E+00 0.000000E+00 1.000000E-01 0.000000E+00 2.000000E-01 1.000000E-01
 0.000000E+00 0.000000E+00 1.000000E-01 2.000000E-01 0.000000E+00 1.000000E-01
 2.000000E-01 2.000000E-01 1.000000E-01 0.000000E+00 2.000000E-01 1.000000E-01
 0.000000E+00 2.000000E-01 0.000000E+00 2.000000E-01 2.000000E-01 0.000000E+00
 2.000000E-01 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00
OBJECT=     2  NFACETS=   300  OBJNAM = SPHERE1  IOBJTYP =      7  OBJCLASS = VOL-OBJECT
BOUNDING BOX= 0.000000E+00 1.000000E+00 0.000000E+00 1.000000E+00 0.000000E+00 1.000000E-01
* clip art rot=   1 a,b,g  0.000000E+00 0.000000E+00 0.000000E+00
 5.000000E-01 5.000000E-01 0.000000E+00 9.990100E-01 5.314000E-01 0.000000E+00
 1.000000E+00 5.000000E-01 0.000000E+00 5.000000E-01 5.000000E-01 0.000000E+00
 1.000000E+00 5.000000E-01 0.000000E+00 9.990100E-01 5.314000E-01 0.000000E+00
 9.990100E-01 5.314000E-01 1.000000E-01 1.000000E+00 5.000000E-01 1.000000E-01
 5.000000E-01 5.000000E-01 1.000000E-01 1.000000E+00 5.000000E-01 1.000000E-01
 9.990100E-01 5.314000E-01 1.000000E-01 5.000000E-01 5.000000E-01 1.000000E-01
 5.000000E-01 5.000000E-01 0.000000E+00 9.960600E-01 5.626700E-01 0.000000E+00
The FACETDAT files contain sections beginning 'OBJECT 1', 'OBJECT 2', etc.

The first three lines (apart from NFACETS= ) are derived directly from what is in Q1; but the NFACETS value, and the remaining lines are derived indirectly, by way of the 'GEOMETRY' line.

Thus, since the 'RELIEF' object has the box-like shape indicated by 'cubet', the number of facets is 6; whereas the object named 'SPHERE1' (somewhat inappropriately, since a cylinder is in question) has 360 facets, that being the number chosen by whoever created the file 'cylinder.dat', which is to be found, incidentally, in \phoenics\d_satell\d_object\public\shapes .

The remaining lines of each section of the facetdat file contain the x/y/z coordinates of the corners of the facets. Since each facet has four corners, and there are 6 real numbers on each line, two lines have to be devoted to each facet.

Therefore, as is evident, the six-facetted 'RELIEF' object has 12 lines of corner values; and (as is not evident because they would take up too much space) the 'cylinder' object needs 720 lines.

FACETDAT files can therefore be very long indeed.