Adding data to a STEP file.

Hello,

> Hello again,

> My code now looks like this:

Sorry, but this is not enough: to get this entity properly initialised, you should properly initialise all entities that it refers. In your case with StepVisual_TextLiteral entity, it is placement, textPath and font that you have to initialize by setting real data to them, for instance:

StepGeom_Axis2Placement placement;

Handle(StepGeom_Axis2Placement3d) placement3d =new StepGeom_Axis2Placement3d;

Handle( TCollection_HAsciiString ) p3dname = new TCollection_HAsciiString( "" );

placement3d->Init ( p3dname, gp_Pnt(0,0,0),Standard_False,0,Standard_False,0);

... and so on... Sorry, this is a way in which STEP works, you often have to put a lot of surplus information. Perhaps TextLiteral is not exactly what you need.

> Handle(StepVisual_TextLiteral) sysLevelPart
> = new StepVisual_TextLiteral();

> Handle( TCollection_HAsciiString ) sysLvlTag
> = new TCollection_HAsciiString(
> "SYS_LVL" );

> Handle( TCollection_HAsciiString ) value =
> new TCollection_HAsciiString(
> "value" );

> StepGeom_Axis2Placement placement;

> Handle( TCollection_HAsciiString ) alignment
> = new TCollection_HAsciiString( ""
> );

> StepVisual_TextPath textPath;

> StepVisual_FontSelect font;

> sysLevelPart->Init( sysLvlTag, value,
> placement, alignment, textPath, font );

> writer.Model()->AddWithRefs( sysLevelPart
> );

> This code fails to put an entity in the STEP
> file. What I really want to do is to attach
> boolean, text, integer or floating point
> data to geometry entities that have already
> been transferred to the writer object. The
> values themselves have no predefined meaning
> in the STEP file - they only have meaning to
> applications that will read the STEP file.
> For example, one parameter is an integer key
> value in a database that indicates what
> surface property should be attached to a
> given shape. Clearly, this data is not a
> "STEP" data item, but I want to
> store it as a STEP entity that complies with
> AP214 so that another application can read
> the file and get the data.

You have two variants:

a) try to find construction defined in STEP AP214 that allows to store the kind of data you want, and use it. This will allow you to create STEP files that will be understood by other applications. However, this can be not easy, for instance, to simply assign a color to a sinngle geometric entity in STEP according to AP214, you have to create 19 new entities.

b) or put your data in your own, specific way. Right method would be to create your own STEP entities, but it is not easy... Or you may use existing STEP entities, for instance, put your data in some entities inheriting from StepRepr_RepresentationItem and connect them to your target entities with help of StepRepr_MappedItem.

The simplest way would be to encode all your data into text string and put it directly to 'name' field of your target geometric entity of interest.

Best Regards,

Andrey

> My code above simply tries to create a valid
> STEP AP214 text entity and put it in the
> file. In addition to this I need to learn
> how to make that entity refer back to a
> geometrical shape that is already in the
> writer object. The StepVisual_TextLiteral
> entity that I am trying to use may not be
> the most appropriate object to use since it
> includes font and placement data which is
> irrelevant to my intended purpose. I have
> tried to use
> StepBasic_ProductDefinitionRelationship to
> make the text entity refer back to a
> geometrical shape , but without success.

> Thanks again for your help,

> -- Shaun Bloom