Package com.luciad.format.ifc

Class TLcdIFCModelDecoder

java.lang.Object
com.luciad.format.ifc.TLcdIFCModelDecoder
All Implemented Interfaces:
ILcdInputStreamFactoryCapable, ILcdModelDecoder, ILcdStatusSource
@LcdService(service=ILcdModelDecoder.class, priority=20000) public class TLcdIFCModelDecoder extends Object implements ILcdModelDecoder, ILcdStatusSource, ILcdInputStreamFactoryCapable

This model decoder decodes IFC files into an ILcdModel. For more information on how this model decoder handles IFC files, please consult The IFC data format article.

Input

File Required Entry point Description
*.ifc x x A supported ifc file.
or
File Required Entry point Description
*.ifc.index x x A text file containing a list of supported ifc files (one file per line) that belong to the same project and that have the same reference. Refer to the Combining multiple IFC files article for more details.

Supported file transfer protocols

This model decoder supports all transfer protocols that are supported by the InputStreamFactory of this decoder when working with an .ifc file. When using a .ifc.index file as entry point, the model decoder needs to find the root files which is done by finding files on the file system directly.

Model reference

IFC data can contain geo-referencing information themselves, but that is not supported by this decoder. This section describes what strategies this decoder uses to find a suitable reference for the data.

  1. The decoder obtains the model reference from an ILcdModelReferenceDecoder, which decodes the reference from an additional model reference file placed next to the data file. The default reference decoder set on this model decoder is based on all model reference decoders annotated with the LcdService annotation. You can add a .prj file with WKT information next to the input data, for example, or a .epgs file with an EPSG code.
  2. Alternatively, you can use a .llh file next to the input data with a single text line containing a longitude, latitude and height coordinate (defined in the default EPSG 4326 reference). This will then be used as a topocentric reference to position your model in the world.
  3. You can set a fallback model reference to be used when no reference information can be found next to the input data: see setDefaultModelReference(com.luciad.model.ILcdModelReference). 
        decoder.setDefaultModelReference(fallbackModelReference);

If no geo-reference information can be found with any of these strategies, then the data will be loaded in its original, non-georeferenced coordinate system.
Note: Data that is decoded in its original coordinate system, cannot be visualized on a geographical map. The dataset must be geo-located with an external tool, after conversion has been done.
This is equivalent to setting a TLcdCartesianReference as fallback reference: 

    decoder.setDefaultModelReference(new TLcdCartesianReference(TLcdDistanceUnit.METRE_UNIT,
                                                                TLcdDistanceUnit.METRE_UNIT,
                                                                TLcdDistanceUnit.METRE_UNIT));

Model structure

This decoder can create 2 different kinds of models:

  • The geometry model: this model contains the IFC geometry. The display name has the suffix "[GEOMETRY]".
  • The features model: this model contains the properties of the IFC structural elements (like doors, walls, etc.), together with their bounding box. This model is a TLcd2DBoundsIndexedModel, its display name has the suffix "[FEATURES]".

With the TLcdBIMDataSource data source, it's possible to specify the model type for the decodeSource(ILcdDataSource) and decodeModelMetadata(ILcdDataSource) methods. The geometry type is assumed for the decode(String) and decodeModelMetadata(String) methods.

The possibility to decode 2 different models is also reflected through the discoverDataSources(java.lang.String) method: it provides 2 ILcdDataSource instances, one for the geometry model and one for the features model, that can both be decoded using the decodeSource(ILcdDataSource)} method.

Model descriptor

The type name of model descriptor is "IFC".

Model elements

The objects in the model depend on the type of the model.

  • The geometry model: this model contains elements that do not implement any public LuciadLightspeed API. However, this model can be used as input for the TLcdOGC3DTilesModelEncoder.
  • The features model: this model contains elements implementing the ILcdDataObject interface. They are also annotated with TLcdHasGeometryAnnotation and TLcdPrimaryKeyAnnotation annotations so this model can for instance be used as input for the TLcdGeoJsonModelEncoder or other encoders supporting ILcdDataObjects.

    These objects have the following properties:

    • FeatureID: a unique ID identifying the feature. This is a sequential number assigned to each feature, based on the order in which the features are processed during the decoding process. Its initial value is specified by the FeatureIDOffset property of the root (see below).
    • Name: a name for the feature. Can be null.
    • Bounds: the 2D bounds of the feature.
    • MinZ: the minimum height of the feature.
    • MaxZ: the maximum height of the feature.
    • Metadata: a Map with uncategorized metadata.
    • MetadataGroups: a Map with metadata grouped per category.

    The features in the model are organized hierarchically. Each feature can reference its parent features through an AncestorPath property and its child features through a Children property. This structure allows you to navigate the feature hierarchy, representing relationships such as the arrangement of building parts within the dataset.

    • AncestorPath: a list that represents the hierarchy from the root feature down to the current feature. Each element in the list is a FeatureID of an ancestor, ordered from the highest-level ancestor (the root feature) to the immediate parent of the current feature. The last element in the list is always the direct parent of the feature.
    • Children: a collection of FeatureIDs pointing to the direct child features of the object.

    The root features have two additional properties compared to the normal feature objects:

    • FeatureIDOffset: the offset that has been used for the featureIDs of its children. This value is non-zero when multiple input files have been combined into an .ifc.index file. The offset value can be used to determine the original identifier in the referenced dataset.
    • SourceName: the source name of the dataset.

Sample code

Obtain the default model containing the geometry: 
    ILcdModelDecoder decoder = new TLcdIFCModelDecoder();
    ILcdModel model = decoder.decode(sourceName);
Obtain the features model: 
    TLcdIFCModelDecoder decoder = new TLcdIFCModelDecoder();
    ILcdModel model = decoder.decodeSource(new TLcdBIMDataSource(sourceName, TLcdBIMDataSource.Type.FEATURES));

Performance tips

If your dataset contains elements outside the area that you are interested in, this can cause problems when converting the geometry to an OGC 3D Tiles dataset, affecting a client application that consumes the 3D Tiles.
To mitigate this problem, you can define a filter that retains only objects inside the area of interest. The tutorial Filtering BIM data describes in depth how you can do that.

Thread safety

  • The decoding of models is thread-safe.
  • The decoded models are thread-safe for read access.

Supported versions and specifications

This decoder supports the following IFC specification versions:

Known limitations

See What are the supported versions and limitations for more information on the limitations of this decoder.

Since:
2022.0

  • Field Details

  • Constructor Details

    • TLcdIFCModelDecoder

      public TLcdIFCModelDecoder()

  • Method Details

    • getDisplayName

      public String getDisplayName()
      Description copied from interface: ILcdModelDecoder
      Returns a short, displayable name for the format that is decoded by this ILcdModelDecoder.
      Specified by:
      getDisplayName in interface ILcdModelDecoder
      Returns:
      the displayable name of this ILcdModelDecoder.

    • canDecodeSource

      public boolean canDecodeSource(String aSourceName)
      Description copied from interface: ILcdModelDecoder
      Checks whether this model decoder can decode the specified data source. It is acceptable for this method to return true for a source name while decode throws an exception for that same source name.

      For performance reasons, we strongly recommend that this will only be a simple test. For example: check the file extension of a file, but not that the file exists or contains expected content.

      Specified by:
      canDecodeSource in interface ILcdModelDecoder
      Parameters:
      aSourceName - the data source to be verified; typically a file name or a URL.
      Returns:
      true if this decoder can likely decode the data specified by the source name, false otherwise.
      See Also:

    • discoverDataSources

      public List<? extends ILcdDataSource> discoverDataSources(String aPath) throws IOException

      Retrieves two ILcdDataSource instances: one for the geometry model and one for the features model.

      Specified by:
      discoverDataSources in interface ILcdModelDecoder
      Parameters:
      aPath - A path to the data source to be decoded; typically a file path or a URL.
      Returns:
      If this model decoder returns true for canDecodeSource(String), it will return a list containing the two ILcdDataSource instances.
      Throws:
      IOException - If this model decoder returns false for canDecodeSource(String) or if any exceptions caused by IO problems or invalid data occur.

    • decodeSource

      public ILcdModel decodeSource(ILcdDataSource aDataSource) throws IOException
      Description copied from interface: ILcdModelDecoder

      Creates a new model from the given data source.

      By default, this method:

      Specified by:
      decodeSource in interface ILcdModelDecoder
      Parameters:
      aDataSource - the ILcdDataSource to be decoded.
      Returns:
      a model containing the decoded data. While null is allowed, implementors are advised to throw an error instead.
      Throws:
      IOException - for any exceptions caused by IO problems or invalid data. Since decoding invalid data almost always results in RunTimeExceptions (NullPointerException, IndexOutOfBoundsException, IllegalArgumentException, ...) on unexpected places, implementations are advised to catch RuntimeExceptions in their decode() method, and wrap them into an IOException, as illustrated in the code snippet below. 
      
 public ILcdModel decodeSource(ILcdDataSource aDataSource) throws IOException {
   try {
     // Perform decoding ...
   } catch (RuntimeException e) {
     throw new IOException(e);
   }
 }
      See Also:

    • decode

      public ILcdModel decode(String aSourceName) throws IOException
      Description copied from interface: ILcdModelDecoder
      Creates a new model from the given data source.
      Specified by:
      decode in interface ILcdModelDecoder
      Parameters:
      aSourceName - the data source to be decoded; typically a file name or a URL.
      Returns:
      A model containing the decoded data. While null is allowed, implementors are advised to throw an error instead.
      Throws:
      IOException - for any exceptions caused by IO problems or invalid data. Since decoding invalid data almost always results in RunTimeExceptions (NullPointerException, IndexOutOfBoundsException, IllegalArgumentException, ...) on unexpected places, implementations are advised to catch RuntimeExceptions in their decode() method, and wrap them into an IOException, as illustrated in the code snippet below. 
      
   public ILcdModel decode( String aSourceName ) throws IOException {
      try (InputStream input = fInputStreamFactory.createInputStream(aSourceName)) {
         // Perform decoding ...
      } catch (RuntimeException e) {
         throw new IOException(e);
      }
   }
      See Also:

    • canDecodeSource

      public boolean canDecodeSource(ILcdDataSource aDataSource)
      Description copied from interface: ILcdModelDecoder

      Checks whether this model decoder can decode the data source(s), identified by the passed ILcdDataSource.

      For performance reasons, we strongly recommend that this will only be a simple test. For example: check the instance class of aDataSource, or check the file extension if it is a TLcdDataSource.

      The default implementation of this method will check if the given ILcdDataSource is a TLcdDataSource. If not, this method returns false. Otherwise, it delegates the source to the ILcdModelDecoder.canDecodeSource(String) method.

      Specified by:
      canDecodeSource in interface ILcdModelDecoder
      Parameters:
      aDataSource - the ILcdModelSource to be verified.
      Returns:
      true if this decoder can likely decode the data specified by aDataSource, false otherwise.
      See Also:

    • decodeModelMetadata

      public TLcdModelMetadata decodeModelMetadata(String aSourceName) throws IOException
      Description copied from interface: ILcdModelDecoder
      Decodes metadata for the specified data source. By default, this decodes the model and returns the model metadata found on that model. Implementations can override this method to speed up the retrieval.
      Specified by:
      decodeModelMetadata in interface ILcdModelDecoder
      Parameters:
      aSourceName - the data source to be decoded; typically a file name or a URL.
      Returns:
      the model metadata for the data source, never null.
      Throws:
      IOException - if the metadata cannot be decoded for some reason.
      See Also:

    • decodeModelMetadata

      public TLcdModelMetadata decodeModelMetadata(ILcdDataSource aDataSource) throws IOException
      Description copied from interface: ILcdModelDecoder
      Decodes metadata for the specified data source. By default, this decodes the model and returns the model metadata found on that model. Implementations can override this method to speed up the retrieval.
      Specified by:
      decodeModelMetadata in interface ILcdModelDecoder
      Parameters:
      aDataSource - the data source to be decoded.
      Returns:
      the model metadata for the data source, never null.
      Throws:
      IOException - if the metadata cannot be decoded for some reason.
      See Also:

    • decodeFeatures

      public ILcdModel decodeFeatures(String aSourceName) throws IOException
      Creates a new model from the given data source. This model contains the metadata of the 'structural elements' of the given IFC data source. The elements of this model implement the ILcdDataObject interface.
      Parameters:
      aSourceName - the data source to be decoded; typically a file name or a URL.
      Returns:
      A model containing the feature data.
      Throws:
      NullPointerException - if aSourceName is null.
      IOException - for any exceptions caused by IO problems or invalid data
      InterruptedIOException - when the thread on which this method is called is interrupted

    • setDefaultModelReference

      public void setDefaultModelReference(ILcdModelReference aModelReference)

    • getDefaultModelReference

      public ILcdModelReference getDefaultModelReference()

    • addStatusListener

      public void addStatusListener(ILcdStatusListener aListener)
      Description copied from interface: ILcdStatusSource

      Registers the given listener so it will receive status events from this source.

      In case you need to register a listener which keeps a reference to an object with a shorter life-time than this status source, you can use a ALcdWeakStatusListener instance as status listener.

      Specified by:
      addStatusListener in interface ILcdStatusSource
      Parameters:
      aListener - The listener to be notified when the status has changed.

    • removeStatusListener

      public void removeStatusListener(ILcdStatusListener aListener)
      Description copied from interface: ILcdStatusSource
      Removes the specified listener so it is no longer notified.
      Specified by:
      removeStatusListener in interface ILcdStatusSource
      Parameters:
      aListener - The listener to remove.

    • setInputStreamFactory

      public void setInputStreamFactory(ILcdInputStreamFactory aInputStreamFactory)
      Description copied from interface: ILcdInputStreamFactoryCapable
      Sets the input stream factory to be used.
      Specified by:
      setInputStreamFactory in interface ILcdInputStreamFactoryCapable
      Parameters:
      aInputStreamFactory - the input stream factory to be used.

    • getInputStreamFactory

      public ILcdInputStreamFactory getInputStreamFactory()
      Description copied from interface: ILcdInputStreamFactoryCapable
      Returns the input stream factory that is used.
      Specified by:
      getInputStreamFactory in interface ILcdInputStreamFactoryCapable
      Returns:
      the input stream factory that is used.

    • getModelReferenceDecoder

      public ILcdModelReferenceDecoder getModelReferenceDecoder()
      Returns the decoder used to produce model references.
      Returns:
      the decoder to produce model references.
      See Also:

    • setModelReferenceDecoder

      public void setModelReferenceDecoder(ILcdModelReferenceDecoder aModelReferenceDecoder)
      Sets the decoder to use to produce model references for models created with this decoder.
      Parameters:
      aModelReferenceDecoder - the decoder to use to produce model references for models created with this decoder.
      See Also: