请问哪位知道STEP交换标准具体内容？

各位：
     小弟想了解STEP（Standard for Exchange of Product Model Data）标准，请指点。下面的内容是我把一个CATPart另存为STEP文件后的内容：
  
ISO-10303-21;
HEADER;
FILE_DESCRIPTION(('CATIA V5 STEP Exchange'),'2;1');
  
FILE_NAME('C:\\Documents and Settings\\1001\\My Documents\\1@@@.stp','2005-03-04T06:40:09+00:00',('none'),('none'),'CATIA Version 5 Release 13 (IN-9)','CATIA V5 STEP AP203','none');
  
FILE_SCHEMA(('CONFIG_CONTROL_DESIGN'));
  
ENDSEC;
DATA;
#5=PRODUCT('Part1','','',(#2)) ;
#1=APPLICATION_CONTEXT('configuration controlled 3D design of mechanical parts and assemblies') ;
#14=PRODUCT_DEFINITION(' ',' ',#6,#3) ;
#16=SECURITY_CLASSIFICATION(' ',' ',#15) ;
#15=SECURITY_CLASSIFICATION_LEVEL('unclassified') ;
#47=CARTESIAN_POINT(' ',(0.,0.,0.)) ;
#52=CARTESIAN_POINT('Axis2P3D Location',(-40.,60.,0.)) ;
#57=CARTESIAN_POINT('Line Origine',(-40.,60.,10.)) ;
#61=CARTESIAN_POINT('Vertex',(-40.,60.,0.)) ;
#63=CARTESIAN_POINT('Vertex',(-40.,60.,20.)) ;
#66=CARTESIAN_POINT('Line Origine',(-40.,25.,0.)) ;
#70=CARTESIAN_POINT('Vertex',(-40.,-10.,0.)) ;
#73=CARTESIAN_POINT('Line Origine',(-40.,-10.,10.)) ;
#77=CARTESIAN_POINT('Vertex',(-40.,-10.,20.)) ;
#80=CARTESIAN_POINT('Line Origine',(-40.,25.,20.)) ;
#92=CARTESIAN_POINT('Axis2P3D Location',(80.,-10.,0.)) ;
#97=CARTESIAN_POINT('Line Origine',(20.,-10.,0.)) ;
#101=CARTESIAN_POINT('Vertex',(80.,-10.,0.)) ;
#104=CARTESIAN_POINT('Line Origine',(80.,-10.,10.)) ;
#108=CARTESIAN_POINT('Vertex',(80.,-10.,20.)) ;
#111=CARTESIAN_POINT('Line Origine',(20.,-10.,20.)) ;
#123=CARTESIAN_POINT('Axis2P3D Location',(80.,-10.,0.)) ;
#128=CARTESIAN_POINT('Line Origine',(80.,25.,0.)) ;
#132=CARTESIAN_POINT('Vertex',(80.,60.,0.)) ;
#135=CARTESIAN_POINT('Line Origine',(80.,60.,10.)) ;
#139=CARTESIAN_POINT('Vertex',(80.,60.,20.)) ;
#142=CARTESIAN_POINT('Line Origine',(80.,25.,20.)) ;
#154=CARTESIAN_POINT('Axis2P3D Location',(-40.,60.,0.)) ;
#159=CARTESIAN_POINT('Line Origine',(20.,60.,0.)) ;
#164=CARTESIAN_POINT('Line Origine',(20.,60.,20.)) ;
#176=CARTESIAN_POINT('Axis2P3D Location',(0.,0.,0.)) ;
#188=CARTESIAN_POINT('Axis2P3D Location',(0.,0.,20.)) ;
#53=DIRECTION('Axis2P3D Direction',(-1.,0.,0.)) ;
#54=DIRECTION('Axis2P3D XDirection',(0.,-1.,0.)) ;
#58=DIRECTION('Vector Direction',(0.,0.,1.)) ;
#67=DIRECTION('Vector Direction',(0.,-1.,0.)) ;
#74=DIRECTION('Vector Direction',(0.,0.,1.)) ;
#81=DIRECTION('Vector Direction',(0.,-1.,0.)) ;
#93=DIRECTION('Axis2P3D Direction',(0.,1.,0.)) ;
#94=DIRECTION('Axis2P3D XDirection',(-1.,0.,0.)) ;
#98=DIRECTION('Vector Direction',(-1.,0.,0.)) ;
#105=DIRECTION('Vector Direction',(0.,0.,1.)) ;
#112=DIRECTION('Vector Direction',(-1.,0.,0.)) ;
#124=DIRECTION('Axis2P3D Direction',(1.,0.,0.)) ;
#125=DIRECTION('Axis2P3D XDirection',(0.,1.,0.)) ;
#129=DIRECTION('Vector Direction',(0.,1.,0.)) ;
#136=DIRECTION('Vector Direction',(0.,0.,1.)) ;
#143=DIRECTION('Vector Direction',(0.,1.,0.)) ;
#155=DIRECTION('Axis2P3D Direction',(0.,-1.,0.)) ;
#156=DIRECTION('Axis2P3D XDirection',(1.,0.,0.)) ;
#160=DIRECTION('Vector Direction',(1.,0.,0.)) ;
#165=DIRECTION('Vector Direction',(1.,0.,0.)) ;
#177=DIRECTION('Axis2P3D Direction',(0.,0.,1.)) ;
#178=DIRECTION('Axis2P3D XDirection',(1.,0.,0.)) ;
#189=DIRECTION('Axis2P3D Direction',(0.,0.,1.)) ;
#190=DIRECTION('Axis2P3D XDirection',(1.,0.,0.)) ;
#48=AXIS2_PLACEMENT_3D(' ',#47,$,$) ;
#55=AXIS2_PLACEMENT_3D('Plane Axis2P3D',#52,#53,#54) ;
#95=AXIS2_PLACEMENT_3D('Plane Axis2P3D',#92,#93,#94) ;
#126=AXIS2_PLACEMENT_3D('Plane Axis2P3D',#123,#124,#125) ;
#157=AXIS2_PLACEMENT_3D('Plane Axis2P3D',#154,#155,#156) ;
#179=AXIS2_PLACEMENT_3D('Plane Axis2P3D',#176,#177,#178) ;
#191=AXIS2_PLACEMENT_3D('Plane Axis2P3D',#188,#189,#190) ;
#40=PRODUCT_DEFINITION_SHAPE(' ',' ',#14) ;
#31=APPROVAL_PERSON_ORGANIZATION(#25,#21,#19) ;
#25=PERSON_AND_ORGANIZATION(#22,#23) ;
#22=PERSON(' ',' ',' ',$,$,$) ;
#23=ORGANIZATION(' ',' ',' ') ;
#21=APPROVAL(#20,' ') ;
#20=APPROVAL_STATUS('not_yet_approved') ;
#19=APPROVAL_ROLE('APPROVER') ;
#13=DATE_AND_TIME(#11,#12) ;
#12=LOCAL_TIME(14,40,9.,#10) ;
#10=COORDINATED_UNIVERSAL_TIME_OFFSET(0,0,.AHEAD.) ;
#86=ORIENTED_EDGE('',*,*,#65,.F.) ;
#87=ORIENTED_EDGE('',*,*,#72,.T.) ;
#88=ORIENTED_EDGE('',*,*,#79,.T.) ;
#89=ORIENTED_EDGE('',*,*,#84,.F.) ;
#117=ORIENTED_EDGE('',*,*,#79,.F.) ;
#118=ORIENTED_EDGE('',*,*,#103,.T.) ;
#119=ORIENTED_EDGE('',*,*,#110,.T.) ;
#120=ORIENTED_EDGE('',*,*,#115,.F.) ;
#148=ORIENTED_EDGE('',*,*,#110,.F.) ;
#149=ORIENTED_EDGE('',*,*,#134,.T.) ;
#150=ORIENTED_EDGE('',*,*,#141,.T.) ;
#151=ORIENTED_EDGE('',*,*,#146,.F.) ;
#170=ORIENTED_EDGE('',*,*,#141,.F.) ;
#171=ORIENTED_EDGE('',*,*,#163,.T.) ;
#172=ORIENTED_EDGE('',*,*,#65,.T.) ;
#173=ORIENTED_EDGE('',*,*,#168,.F.) ;
#182=ORIENTED_EDGE('',*,*,#163,.F.) ;
#183=ORIENTED_EDGE('',*,*,#134,.F.) ;
#184=ORIENTED_EDGE('',*,*,#103,.F.) ;
#185=ORIENTED_EDGE('',*,*,#72,.F.) ;
#194=ORIENTED_EDGE('',*,*,#84,.T.) ;
#195=ORIENTED_EDGE('',*,*,#115,.T.) ;
#196=ORIENTED_EDGE('',*,*,#146,.T.) ;
#197=ORIENTED_EDGE('',*,*,#168,.T.) ;
#51=CLOSED_SHELL('Closed Shell',(#91,#122,#153,#175,#187,#199)) ;
#59=VECTOR('Line Direction',#58,1.) ;
#68=VECTOR('Line Direction',#67,1.) ;
#75=VECTOR('Line Direction',#74,1.) ;
#82=VECTOR('Line Direction',#81,1.) ;
#99=VECTOR('Line Direction',#98,1.) ;
#106=VECTOR('Line Direction',#105,1.) ;
#113=VECTOR('Line Direction',#112,1.) ;
#130=VECTOR('Line Direction',#129,1.) ;
#137=VECTOR('Line Direction',#136,1.) ;
#144=VECTOR('Line Direction',#143,1.) ;
#161=VECTOR('Line Direction',#160,1.) ;
#166=VECTOR('Line Direction',#165,1.) ;
#201=ADVANCED_BREP_SHAPE_REPRESENTATION('NONE',(#200),#46) ;
#49=SHAPE_REPRESENTATION(' ',(#48),#46) ;
#91=ADVANCED_FACE('',(#90),#56,.T.) ;
#122=ADVANCED_FACE('',(#121),#96,.F.) ;
#153=ADVANCED_FACE('',(#152),#127,.T.) ;
#175=ADVANCED_FACE('',(#174),#158,.F.) ;
#187=ADVANCED_FACE('',(#186),#180,.F.) ;
#199=ADVANCED_FACE('',(#198),#192,.T.) ;
#4=APPLICATION_PROTOCOL_DEFINITION('international standard','config_control_design',1994,#1) ;
#32=APPROVAL_DATE_TIME(#13,#21) ;
#200=MANIFOLD_SOLID_BREP('PartBody',#51) ;
#11=CALENDAR_DATE(2005,4,3) ;
#30=CC_DESIGN_APPROVAL(#21,(#16,#6,#14)) ;
#18=CC_DESIGN_DATE_AND_TIME_ASSIGNMENT(#13,#17,(#16)) ;
#29=CC_DESIGN_DATE_AND_TIME_ASSIGNMENT(#13,#28,(#14)) ;
#17=DATE_TIME_ROLE('classification_date') ;
#28=DATE_TIME_ROLE('creation_date') ;
#27=CC_DESIGN_PERSON_AND_ORGANIZATION_ASSIGNMENT(#25,#26,(#16)) ;
#33=CC_DESIGN_PERSON_AND_ORGANIZATION_ASSIGNMENT(#25,#34,(#6)) ;
#35=CC_DESIGN_PERSON_AND_ORGANIZATION_ASSIGNMENT(#25,#36,(#6,#14)) ;
#37=CC_DESIGN_PERSON_AND_ORGANIZATION_ASSIGNMENT(#25,#38,(#5)) ;
#26=PERSON_AND_ORGANIZATION_ROLE('classification_officer') ;
#34=PERSON_AND_ORGANIZATION_ROLE('design_supplier') ;
#36=PERSON_AND_ORGANIZATION_ROLE('creator') ;
#38=PERSON_AND_ORGANIZATION_ROLE('design_owner') ;
#39=CC_DESIGN_SECURITY_CLASSIFICATION(#16,(#6)) ;
#202=SHAPE_REPRESENTATION_RELATIONSHIP(' ',' ',#49,#201) ;
#3=DESIGN_CONTEXT(' ',#1,'design') ;
#65=EDGE_CURVE('',#62,#64,#60,.T.) ;
#72=EDGE_CURVE('',#62,#71,#69,.T.) ;
#79=EDGE_CURVE('',#71,#78,#76,.T.) ;
#84=EDGE_CURVE('',#64,#78,#83,.T.) ;
#103=EDGE_CURVE('',#71,#102,#100,.F.) ;
#110=EDGE_CURVE('',#102,#109,#107,.T.) ;
#115=EDGE_CURVE('',#78,#109,#114,.F.) ;
#134=EDGE_CURVE('',#102,#133,#131,.T.) ;
#141=EDGE_CURVE('',#133,#140,#138,.T.) ;
#146=EDGE_CURVE('',#109,#140,#145,.T.) ;
#163=EDGE_CURVE('',#133,#62,#162,.F.) ;
#168=EDGE_CURVE('',#140,#64,#167,.F.) ;
#85=EDGE_LOOP('',(#86,#87,#88,#89)) ;
#116=EDGE_LOOP('',(#117,#118,#119,#120)) ;
#147=EDGE_LOOP('',(#148,#149,#150,#151)) ;
#169=EDGE_LOOP('',(#170,#171,#172,#173)) ;
#181=EDGE_LOOP('',(#182,#183,#184,#185)) ;
#193=EDGE_LOOP('',(#194,#195,#196,#197)) ;
#90=FACE_OUTER_BOUND('',#85,.T.) ;
#121=FACE_OUTER_BOUND('',#116,.T.) ;
#152=FACE_OUTER_BOUND('',#147,.T.) ;
#174=FACE_OUTER_BOUND('',#169,.T.) ;
#186=FACE_OUTER_BOUND('',#181,.T.) ;
#198=FACE_OUTER_BOUND('',#193,.T.) ;
#45=UNCERTAINTY_MEASURE_WITH_UNIT(LENGTH_MEASURE(0.005),#41,'TOL_CRV','CONFUSED CURVE UNCERTAINTY') ;
#60=LINE('Line',#57,#59) ;
#69=LINE('Line',#66,#68) ;
#76=LINE('Line',#73,#75) ;
#83=LINE('Line',#80,#82) ;
#100=LINE('Line',#97,#99) ;
#107=LINE('Line',#104,#106) ;
#114=LINE('Line',#111,#113) ;
#131=LINE('Line',#128,#130) ;
#138=LINE('Line',#135,#137) ;
#145=LINE('Line',#142,#144) ;
#162=LINE('Line',#159,#161) ;
#167=LINE('Line',#164,#166) ;
#2=MECHANICAL_CONTEXT(' ',#1,'mechanical') ;
#24=PERSONAL_ADDRESS(' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',(#22),' ') ;
#56=PLANE('Plane',#55) ;
#96=PLANE('Plane',#95) ;
#127=PLANE('Plane',#126) ;
#158=PLANE('Plane',#157) ;
#180=PLANE('Plane',#179) ;
#192=PLANE('Plane',#191) ;
#43=PLANE_ANGLE_MEASURE_WITH_UNIT(PLANE_ANGLE_MEASURE(0.0174532925199),#42) ;
#7=PRODUCT_CATEGORY('part',$) ;
#9=PRODUCT_CATEGORY_RELATIONSHIP(' ',' ',#7,#8) ;
#6=PRODUCT_DEFINITION_FORMATION_WITH_SPECIFIED_SOURCE('',' ',#5,.NOT_KNOWN.) ;
#8=PRODUCT_RELATED_PRODUCT_CATEGORY('detail',$,(#5)) ;
#50=SHAPE_DEFINITION_REPRESENTATION(#40,#49) ;
#62=VERTEX_POINT('',#61) ;
#64=VERTEX_POINT('',#63) ;
#71=VERTEX_POINT('',#70) ;
#78=VERTEX_POINT('',#77) ;
#102=VERTEX_POINT('',#101) ;
#109=VERTEX_POINT('',#108) ;
#133=VERTEX_POINT('',#132) ;
#140=VERTEX_POINT('',#139) ;
#41=(LENGTH_UNIT()NAMED_UNIT(*)SI_UNIT(.MILLI.,.METRE.)) ;
#42=(NAMED_UNIT(*)PLANE_ANGLE_UNIT()SI_UNIT($,.RADIAN.)) ;
#44=(NAMED_UNIT(*)SI_UNIT($,.STERADIAN.)SOLID_ANGLE_UNIT()) ;
#46=(GEOMETRIC_REPRESENTATION_CONTEXT(3)GLOBAL_UNCERTAINTY_ASSIGNED_CONTEXT((#45))GLOBAL_UNIT_ASSIGNED_CONTEXT((#41,#42,#44))REPRESENTATION_CONTEXT(' ',' ')) ;
ENDSEC;
END-ISO-10303-21;
请与我联系，QQ:58567710

请高手指点阿

还真没有注意过，我也想知道

高手请进。

没有人知道吗？

高手来看看啊