SECPASS
1
BRL-CAD
BRL-CAD

# secpass

interrogates an mged file to obtain the conductivity table of the PRISM-ready input file or a generic thermal data file

      secpass
        model.g
        objects

## DESCRIPTION

Secpass is an interactive program used to create a conductivity table for the PRISM-ready input file (when used in conjunction with firpass) or a generic thermal data file. The conduction approximation is based on the following formula from the PRISM manual.

    	RK(i,j) =             1
    		    ---------------------------
    		      L(i)/K(i)A + L(j)/K(j)A

    	RK(i,j) - conductivity between region i and j
    	L(i)    - conduction path length of region i
    	L(j)    - conduction path length of region j
    	K(i)    - conductivity of material of region i
    	K(j)    - conductivity of material of region j
    	A       - shared surface area

The conduction path length is a distance between the centroid of the region and the shared surface. The user may select the average, root mean squared (rms), minimum, or maximum distance for the length.

The following information about each region is obtained from secpass when creating a PRISM ready file.

    	number (same scheme as in firpass)
    	number of region there is conduction between
    	conduction

The following information about each region is obtained when creating a generic thermal data file

    	number
    	number of adjacent regions
    	shared area of each adjacent region (m**2)
    	conduction distance (m)

## EXAMPLE

The following is an example from an interactive session.

    $ secpass test.veh.g vehicle air
    Write output to standard out (0) or a file(1) not at all (2)?  2
    Enter name of file that has second pass information
    in it (15 char max).  veh.f.2nd
    Enter type of output file to be generated.
    	 0 - PRISM File
    	 1 - Generic File
    0
    Enter name of file to be created for PRISM conductivity
    information (15 char max).  veh.s.con
    Which release of PRISM is being used, 2.0 (2) or 3.0 (3)?  3
    Which length calculation should be used when
    computing conduction
    between regions?
    	1 - average length
    	2 - rms length
    	3 - minimum length
    	4 - maximum length
    3
    Enter name of file to be created for conductivity
    table (15 char max).  veh.s.tbl
    Enter name of material file (15 char max).  prp
    Enter name of error file to be created (15 char max).  veh.s.err
    Should there be 3 sets of orthogonal rays fired (0) or 1 set (1)?
    	3
    3 sets of orthogonal rays will be fired.
    Database title:  test vehicle for use with irprep programs
    Number of regions in mged file:  21
    Mallocing arrays.
    cond malloced
    loop malloced
    All variables zeroed.
    second pass file opened
    The number of regions read was 21
    Center of bounding rpp ( 356.500000, 0.000000, 1250.000000 )
    Length of diagonal of bounding rpp:  3829.051456
    Minimums & maximums of grid:
      -3472.551456 - 4185.551456
      -3829.051456 - 3829.051456
      -2579.051456 - 5079.051456

    Model minimum & maximum.
    	X:  -3001.000000 to 3714.000000
    	Y:  -1350.000000 to 1350.000000
    	Z:  0.000000 to 2500.000000

    Enter spacing (mm) between fired rays.  10

    grid spacing:  10.000000

    Shooting down 1st axis.

    Shooting down the 2nd axis.

    Shooting down the 3rd axis.

    SUMMARY OF FILES USED & CREATED
    	.g file used:  test.veh.g
    	regions used:
    		vehicle
    		air
    	file containing second pass information:  veh.f.2nd
    	material file used:  prp
    	conductivity file created:  veh.s.con
    	  (format is PRISM 3.0)
    	conductivity table file created:  veh.s.tbl
    	error file created:  veh.s.err

    Freeing memory.

## CHANGES SINCE BRL-CAD RELEASE 4.0

1. Made the numbering scheme for regions the same throughout all irprep programs, i.e. region numbers start at one not zero. This affects the format of the diagnostic and error files.

2. Correct the format of the conductivity file for PRISM. The larger region number must come first.

3. The user is given a choice of a 2.0 PRISM format or a 3.0 PRISM format.

4. Some diagnostic information is no longer printed out.

5. The user is given a choice of firing one set of rays or three sets of orthogonal rays.

## SEE ALSO

firpass 1, shapefact 1, all_sf 1, showtherm 1, ir-X(1), ir-sgi 1, pictx 1, pictsgi 1, User's Manual for IRPREP (BRL-SP-96), Computer Programs for Generating an Input File for PRISM and Displaying PRISM Results (BRL report in progress)

## AUTHOR

Susan A. Coates

## COPYRIGHT

This software is Copyright (c) 1991-2013 by the United States Government as represented by U.S. Army Research Laboratory.

## BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to <devs@brlcad.org>.