PDF Reader

Portable Document Format (PDF)
File Extension	PDF [1]
Supported Versions	All versions
Platforms
Tessellation	Read from file
B-rep	Supported
PMI	Supported

Portable Document Format (PDF) is a versatile file format developed by Adobe. It is commonly used for documents, including text, images, and vector graphics. The format can also include embedded 3D models, mentioned as 3D annotations..

Our support for PDF covers reading 3D annotations in PRC or U3D streams stored within any version of a PDF file on all platforms.

[1]

While .pdf is the usual extension for PDF files, HOOPS Exchange identifies and reads from PDF files with any extension.

Loading a PDF Model

PDF files can contain multiple data streams, each encoding a 3D annotation. As a result, using basic functions like A3DAsmModelFileLoadFromFile() or A3DAsmModelFileGet() will only work if you are interested in the first 3D annotation stored in the PDF file, because these functions are designed to handle only a single data stream.

To load 3D content from a PDF file, you first need to extract the 3D data streams using A3DGet3DPDFStreams(). This function retrieves an array of 3D streams, allowing you to choose which one to process.

Handling PRC and U3D Data

Once the 3D streams are extracted, they are stored in a C-style array of A3DStream3DPDFData objects. For each stream, you can determine if it contains PRC data by checking the m_bIsPrc flag. If the stream is not PRC, it contains U3D data.

You can then dump each stream into files and load them into model files using A3DAsmModelFileLoadFromFile(). PRC streams, however, can be loaded directly from memory using A3DAsmModelFileLoadFromPrcStream().

The following example demonstrates how to load the first 3D stream from a PDF, check its format, and handle the stream appropriately:

A3DStream3DPDFData* pStream3DPDFData;
A3DInt32 iNumStreams;
A3DGet3DPDFStreams((char*) pcFileName, &pStream3DPDFData, &iNumStreams);

// a real use case might parse every stream in the input file. Here, we just take the first one (pStream3DPDFData[0]).
if (pStream3DPDFData[0].m_bIsPrc) // test whether the data is PRC or U3D
{
        // even an input PRC file must be read in memory and mapped into modelfile data structures
        A3DRWParamsPrcReadHelper* pPrcReadHelper;
        A3DAsmModelFileLoadFromPrcStream(pStream3DPDFData[0].m_pcStream, pStream3DPDFData[0].m_iLength, &pPrcReadHelper, ppModelFile);
}
else
{
        // A U3D stream must first be stored as a physical file, then read by A3DAsmModelFileLoadFromFile
        sprintf(tempfilename, "%s.u3d", OUT_FILE);
        FILE * pFile = fopen(tempfilename , "wb");

        fwrite(pStream3DPDFData[0].m_pcStream, 1, pStream3DPDFData[0].m_iLength , pFile);
        fclose(pFile);

        // physical file to stream
        A3DAsmModelFileLoadFromFile(tempfilename, sReadParam, ppModelFile);

        // the temp file can be disposed of afterwards
        remove(tempfilename);
}

// Release memory for stream array
A3DGet3DPDFStreams(0, &pStream3DPDFData, &iNumStreams);

Loading a PDF with A3DAsmModelFileLoadFromFile

You can load a PDF file containing PRC or U3D streams using A3DAsmModelFileLoadFromFile(), but there are some limitations:

• Only the first stream in the PDF will be read; additional streams will be ignored.

• If the stream includes annotations, only the first annotation is processed, and subsequent annotations are disregarded.

To load a PDF file using A3DAsmModelFileLoadFromFile(), use the A3DParamsLoadData structure to customize the loading behavior:

A3DAsmModelFile* pModelFile = 0;

A3DRWParamsLoadData sReadParam;
A3D_INITIALIZE_DATA(A3DRWParamsLoadData, sReadParam);
sReadParam.m_sGeneral.m_bReadSolids = true;

// ... set other A3DRWParamsLoadData fields as necessary

A3DAsmModelFileLoadFromFile("path/to/file.pdf", &sReadParam, &pModelFile);

See Simple Load and Export for more information about loading model files.

Support Capabilities

Since our PDF reader reads streams in either a PRC or and U3D format, the support for reading tessellation data, B-rep and PMI depends on these specific readers.

For more information about their support, see PRC Reader and U3D Reader.

Limitations

Our PDF reader does not read 3D streams from password-protected PDF files.