Запуск PB - производиться довольно оригинально. Наверно, Вы не раз сталкивались с ситуацией, что простого запуска post_builder.bat  недостаточно.
На деле, при запуске post_builder.bat передаются аргументы ( это видно из свойства ярлыка меню и самого post_builder.bat).

"C:\Program Files\UGS\NX 6.0\POSTBUILD\post_builder.bat" "C:\Program 
Files\UGS\NX 6.0\"

Например, запуск Постбилдера 16.3.3 зависел от 25 ниже указанных библиотек: на самом деле ему было нужны всего лишь 2-е! остальные  просто тянулись сборкой.

@echo off

REM================================================
REM PB_HOME is the only env var referenced in the Post Builder source codes.
REM It should be set base on the Post Builder installation.
REM================================================
set base=%1
set base_dir=%base:"=%
set PB_HOME=%base_dir%\postbuild

REM================================================
REM UG DLL's search path.
REM================================================
set PATH=%base_dir%\UGII;%PATH%

REM================================================
REM Some vars for Tcl etc.
REM================================================
set PB_TCL=%PB_HOME%\tcl
set TCL_LIBRARY=%PB_TCL%\share\tcl8.0
set TK_LIBRARY=%PB_TCL%\share\tk8.0
set TIX_LIBRARY=%PB_TCL%\share\tix4.1

REM================================================
REM Tcl DLL search path
REM================================================
set PATH=%PB_TCL%\exe;%PATH%

REM================================================
REM Start Post Builder
REM================================================
"%PB_HOME%\app\post_builder.exe"

REM================================================
REM Post Builder returns 0 as the result of a successful run, otherwise
REM it returns a non-zero value.
REM================================================
if ERRORLEVEL 0 goto END
pause

:END

@echo off

REM================================================
REM PB_HOME is the only env var referenced in the Post Builder source codes.
REM It should be set base on the Post Builder installation.
REM================================================
set base=%1
set base_dir=%base:"=%
set PB_HOME=%base_dir%\postbuild

REM================================================
REM UG DLL's search path.
REM================================================
set PATH=%base_dir%\UGII;%PATH%

REM================================================
REM Some vars for Tcl etc.
REM================================================
set PB_TCL=%PB_HOME%\tcl

rem<01-21-08 gsl> Corrected env vars
rem set TCL_LIBRARY=%PB_TCL%\share\tcl8.0
rem set TK_LIBRARY=%PB_TCL%\share\tk8.0
rem set TIX_LIBRARY=%PB_TCL%\share\tix4.1

set TCL_LIBRARY=%PB_TCL%\share\tcl8.4
set TK_LIBRARY=%PB_TCL%\share\tk8.4
set TIX_LIBRARY=%PB_TCL%\share\tix8.4

REM================================================
REM Tcl DLL search path
REM================================================
set PATH=%PB_TCL%\exe;%PATH%

REM================================================
REM Start Post Builder
REM================================================
"%PB_HOME%\app\post_builder.exe" "%*"

REM================================================
REM Post Builder returns 0 as the result of a successful run, otherwise
REM it returns a non-zero value.
REM================================================
if ERRORLEVEL 0 goto END
pause

IMPORTS TABLE:

libufun.dll
----- -----
3067 UF_get_fail_message
1171 UF_MISC_set_program_name
3069 UF_initialize
3079 UF_terminate

libuglm.dll
----- -----
29 check_license
32 leave_a_module

IMPORTS TABLE:

libufun.dll
----- -----
4552 UF_get_fail_message
4556 UF_initialize
1611 UF_MISC_set_program_name
4567 UF_terminate

libuglm.dll
----- -----
20 UGFLEX_enter_module
26 UGFLEX_set_display
13 UGFLEX_ask_display
24 UGFLEX_leave_module

EXPORTS TABLE:
void __cdecl NXSigningResource(void)

IMPORTS TABLE:

libsyss.dll
----- -----
6025 public: static void __cdecl UGS::Memory::CppMemory::free(void *)
5372 public: static void * cdecl UGS::Memory::CppMemory::allocate(unsigned int)

libjam.dll
----- -----
357 int __cdecl JAM_enter_module(
319 void __cdecl JAM_ask_server_info(char * const,char * const)
447 int __cdecl JAM_leave_module()
327 int __cdecl JAM_check_availability()

libufun.dll
----- -----
5197 UF_terminate
5171 UF_free
356 UF_CFI_spawn
5175 UF_get_fail_message
5180 UF_initialize
1811 UF_MISC_set_program_name
5155 UF_allocate_memory
5185 UF_print_syslog

IMPORTS TABLE:

tcl*.dll
----- -----
311 Tcl_GetVar
327 Tcl_Init
139 Tcl_Alloc
433 Tcl_SetPanicProc
364 Tcl_NewListObj
146 Tcl_AppendStringsToObj
487 Tcl_WrongNumArgs
309 Tcl_GetStringFromObj
303 Tcl_GetObjResult
426 Tcl_SetIntObj
186 Tcl_CreateObjCommand
318 Tcl_GlobalEval
347 Tcl_ListObjLength
440 Tcl_SetVar
319 Tcl_GlobalEvalObj
348 Tcl_ListObjReplace

TK*.DLL
----- -----
362 Tk_Main
356 Tk_Init

tix*.dll
----- -----
202 TkConsoleCreate
132 Tix_Init

Создаются команды в интерпретаторе и он сам: 
proc UI_PB__main_menu {top}

proc UIPB__createGauge {}
proc UIPB__updateGauge {val1 val2}
proc UIPB__destroyGauge {} 

и другие команды.
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