Il formato è emerso per la prima volta negli anni '90 con l'obiettivo di standardizzare non solo i contenuti 3D ma anche dati aggiuntivi specifici per l'uso industriale, come tolleranze e materiali. Conosciuto come standard ISO-10303-21, lo standard per i file STEP è stato rivisto nel corso degli anni per abilitare funzionalità aggiuntive.
I dati 3D all'interno del file STEP sono rappresentati in forma di testo utilizzando una combinazione di forme costituite da facce, bordi e altri dati geometrici. Come accennato, il formato STEP è stato progettato per essere uno standard per lo scambio di modelli 3D, il che significa che ha un supporto diffuso tra le applicazioni CAD e di modellazione 3D, nonché i software di conversione dei file.
000ISO-10303-21;
001HEADER;
002/* Generated by software containing ST-Developer
003 * from STEP Tools, Inc. (www.steptools.com)
004 */
005
006FILE_DESCRIPTION(
007/* description */ (''),
008/* implementation_level */ '2;1');
009
010FILE_NAME(
011/* name */ 'c5.stp',
012/* time_stamp */ '2024-02-05T06:35:35+00:00',
013/* author */ (''),
014/* organization */ (''),
015
016/* authorisation */ '');
017
018FILE_SCHEMA (('AUTOMOTIVE_DESIGN { 1 0 10303 214 3 1 1 }'));
019ENDSEC;
020
021DATA;
022#10=SHAPE_REPRESENTATION_RELATIONSHIP('SRR','None',#22544,#11);
023#11=ADVANCED_BREP_SHAPE_REPRESENTATION($,(#11436),#22538);
024#12=ORIENTED_CLOSED_SHELL($,*,#11433,.F.);
025#13=ORIENTED_CLOSED_SHELL($,*,#11434,.F.);
026#14=ORIENTED_CLOSED_SHELL($,*,#11435,.F.);
027#15=CONICAL_SURFACE($,#11713,0.59315625,0.759762754875772);
028#16=CONICAL_SURFACE($,#11720,0.59315625,0.759762754875772);
029#17=SPHERICAL_SURFACE($,#11545,0.01265625);
030#18=SPHERICAL_SURFACE($,#11591,0.050625);
031#19=SPHERICAL_SURFACE($,#11689,0.050625);
032#20=SPHERICAL_SURFACE($,#11742,0.050625);
033#21=TOROIDAL_SURFACE($,#12201,0.3290625,0.0759375);
034#22=TOROIDAL_SURFACE($,#12206,0.4809375,0.0759375);
035#23=TOROIDAL_SURFACE($,#12211,0.1771875,0.0759375);
036#24=(
037BOUNDED_SURFACE()
038B_SPLINE_SURFACE(2,2,((#16169,#16170,#16171,#16172,#16173,#16174,#16175,
039#16176,#16177),(#16178,#16179,#16180,#16181,#16182,#16183,#16184,#16185,
040#16186),(#16187,#16188,#16189,#16190,#16191,#16192,#16193,#16194,#16195),
041(#16196,#16197,#16198,#16199,#16200,#16201,#16202,#16203,#16204),(#16205,
042#16206,#16207,#16208,#16209,#16210,#16211,#16212,#16213),(#16214,#16215,
043#16216,#16217,#16218,#16219,#16220,#16221,#16222),(#16223,#16224,#16225,
044#16226,#16227,#16228,#16229,#16230,#16231),(#16232,#16233,#16234,#16235,
045#16236,#16237,#16238,#16239,#16240),(#16241,#16242,#16243,#16244,#16245,
046#16246,#16247,#16248,#16249)),.UNSPECIFIED.,.T.,.T.,.F.)
047B_SPLINE_SURFACE_WITH_KNOTS((3,2,2,2,3),(3,2,2,2,3),(-3.14159265358979,
048-1.5707963267949,0.,1.5707963267949,3.14159265358979),(0.,1.5707963267949,
0493.14159265358979,4.71238898038469,6.28318530717959),.UNSPECIFIED.)
050GEOMETRIC_REPRESENTATION_ITEM()
051RATIONAL_B_SPLINE_SURFACE(((1.,0.707106781186548,1.,0.707106781186548,1.,
0520.707106781186548,1.,0.707106781186548,1.),(0.707106781186548,0.500000000000001,
0530.707106781186548,0.500000000000001,0.707106781186548,0.500000000000001,
0540.707106781186548,0.500000000000001,0.707106781186548),(1.,0.707106781186548,
0551.,0.707106781186548,1.,0.707106781186548,1.,0.707106781186548,1.),(0.707106781186548,
0560.500000000000001,0.707106781186548,0.500000000000001,0.707106781186548,
0570.500000000000001,0.707106781186548,0.500000000000001,0.707106781186548),
058(1.,0.707106781186548,1.,0.707106781186548,1.,0.707106781186548,1.,0.707106781186548,
0591.),(0.707106781186547,0.5,0.707106781186547,0.5,0.707106781186547,0.5,
0600.707106781186547,0.5,0.707106781186547),(1.,0.707106781186548,1.,0.707106781186548,
0611.,0.707106781186548,1.,0.707106781186548,1.),(0.707106781186548,0.5,0.707106781186548,
0620.5,0.707106781186548,0.5,0.707106781186548,0.5,0.707106781186548),(1.,
0630.707106781186548,1.,0.707106781186548,1.,0.707106781186548,1.,0.707106781186548,
0641.)))
065REPRESENTATION_ITEM($)
066SURFACE()
067);
A causa del formato basato su testo, i file STEP possono diventare molto grandi quando si salvano dati 3D complessi nel formato. Anche il caricamento dei file STEP nel software di editing può richiedere del tempo, quindi si prega di attendere più tempo durante la modifica di questi file.
