JT_Reader can read files compliant with the JT formats from 8.0 to 10.5 and ISO14306:2012. JT_Writer can write files compliant with the JT formats 9.5 and ISO14306:2012.
The JT format applies compression and encoding when storing data, therefore files can contain many more entities and can take considerably longer time to convert in comparison with files of similar sizes stored in other formats (e.g. IGES, STEP, etc).
The JT converter uses the Parasolid converter to import XT B-Rep elements from JT files and to export B-Rep representations to JT format.
CAD Exchanger can read and write both monolithic files and assemblies with external references.
Import | Export |
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(*) JT_Reader recognizes JT B-Rep and XT B-Rep; JT_Writer uses XT B-Rep to store BRep representations.
Below tables shows how JT entities are mapped into CAD Exchanger entities after import.
JT Entity | CAD Exchanger Entity |
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Meta Data Node Element | ModelData_Assembly |
Instance Node Element | ModelData_Instance |
Part Node Element | ModelData_Part |
JT Entity | CAD Exchanger Entity |
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Tri-Strip Set Shape LOD Element | ModelData_IndexedTriangleSet |
Polyline Set Shape LOD Element | ModelData_PolyLineSet |
Point Set LOD Element | ModelData_PolyPointSet |
The JT import parameters are controlled by JT_ReaderParameters. The following table contains a list of parameters for JT import:
Parameter | Default value | Description |
---|---|---|
LayerConversionMode() | None | Specifies the mode of layers import.
Refer to Layers Support for further details. |
ReadPMI() | false | See Base_ReaderParameters::ReadPMI(). |
The JT export parameters are controlled by JT_WriterParameters. The following table contains a list of parameters for JT export:
Parameter | Default value | Description |
---|---|---|
FileSplitMode() | Monolithic | Defines the mode of splitting the resulting JT file. Supports per part, shattered and monlithic modes:
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WriteBRepRepresentation() | true | See Base_WriterParameters::WriteBRepRepresentation(). Without B-Rep representations a jt file may not be effectively usable/loadable by some CAD systems or application which expect them. |
WritePolyRepresentation() | true | See Base_WriterParameters::WritePolyRepresentation(). If more than one polygonal representations is present in model, then all of them are written. If there is no polygonal representation then computes it on the fly from available B-Rep representation. Without polygonal representations a jt file may not be viewable by some 3rd-party viewers (e.g. Siemens jt2go) which are only able to visualize tessellated representations. |
LayerConversionMode() | None | Specifies the mode of layers export.
Refer to Layers Support for further details. |
OverrideInstanceNames() | false | Specifies whether original instance names should be overridden by parts/assemblies the instances refer to. If false (by default) then original names of parts/assemblies/instances are mapped to JT. However some CAD systems (e.g. Solid Edge ST6) may not be able to import files with instance names distinct from parts/assemblies they refer to, even if other applications (e.g. jt2go, NX) read such files fine. When OverrideInstanceNames is true then a part (assembly) will use a source name if specified, or name of the first instance, or otherwise 'unspecified'. Instance(s) will always use a part's (assembly's) name (or 'unspecified'), i.e. will always be equal to the referred part (assembly's). |
WritePMI() | false | See Base_WriterParameters::WritePMI(). |
When parsing JT files with external references (i.e. per-part or shattered assemblies), external files are parsed in a lazy manner. That is, parsing a particular JT file is deferred until a resulting scene graph element (an assembly or a part) representing that JT file is accessed for the first time, e.g. via accepting a visitor.
This allows to incrementally load elements of the model, significantly enhances application response and reduces peak memory footprint when working with large assemblies. To take most advantage of this feature, it can be used in conjunction with the option DelayedConversion() which will delay conversion in a user's application. In that case, initial parsing a JT file will be instant, and actual parsing and conversion will only be performed for those scene graph elements which will be of user's interest and only when it is needed for the first time.
To be added...
Although JT format does not explicitly define layer entities, some JT-aware applications such as Siemens Teamcenter are able to recognize layer structures described with the help of string properties following some conventions. CAD Exchanger is able to respect these conventions in order to convert to/from layer objects.
The modes of layer import and export are controlled by JT_ReaderParameters::LayerConversionMode() and JT_WriterParameters::LayerConversionMode() respectively.
Depending on the values behavior can be as follows:
Notes (for LayerFilter mode):