Load STEP from memory instead of file - Forum Open Cascade Technology

Alfonso Tamés
Wed, 05/24/2017 - 00:27

Forums:

Data Exchange and Application Framework

Hi,

Is it possible to open a file directly from a byte array instead of reading a file?

thanks,

Alfonso

Kirill Gavrilov
Wed, 05/24/2017 - 09:17

There is not such functionality (yet).
The feature status can be tracked within issue #0027342 on bug tracker (don't be confused by current status "resolved", existing patch is not ready for using).

Alfonso Tamés
Mon, 05/29/2017 - 08:20

Thanks for the update, I hope it supports C++ streams soon.

All the best,

Alfonso

Martin Walter
Fri, 10/23/2020 - 19:07

Is there any insight on when this will be available for writing step files?

Best regards,

Martin

Kirill Gavrilov
Mon, 11/09/2020 - 12:57

OCCT 7.5.0 has been introduced support for reading STEP files from a C++ stream.
So far, nobody reported the feature request for writing STEP file into stream on OCCT Bugtracker - you can be first:
https://dev.opencascade.org/index.php?q=home/get_involved

haidong ma
Fri, 05/14/2021 - 10:00

add this write stream feature in here: #0032350

Jan Selchow
Tue, 11/01/2022 - 18:52

Hello it seems like the write to Stream Issue has also bin resolved for OCC v7.7.0
Could someone post a working example for both reading from and writing to byte[]?
Also is this only for STEP or can I also import and export for example GLTFs from/to byte[]?
Thank you.

gkv311 n
Tue, 11/01/2022 - 19:59

Jan Selchow wrote

it seems like the write to Stream Issue has also bin resolved for OCC v7.7.0

"resolved" bug state doesn't mean integration, it means that somebody provided a patch for review.

Dmitrii Pasukhin
Wed, 11/02/2022 - 15:20

Hello,

Writing a STEP file to a stream is integrated into ver. 7.7

// Reading to XCAF
STEPCAFControl_Reader aReader;
std::ifstream aStream;
OSD_OpenStream (aStream, aFilePath, std::ios::in | std::ios::binary);
aReader.ReadStream (aFileNameShort, aStream);
aReader.Transfer (aDoc);

// Writing from XCAF
STEPCAFControl_Writer aWriter;
aWriter.Transfer (aDoc);
std::ofstream aStream;
OSD_OpenStream (aStream, aFilePath, std::ios::out | std::ios::binary);
aWriter.WriteStream (aStream);

Best regards, Dmitrii.

Dmitrii Pasukhin
Wed, 11/02/2022 - 18:30

Additionally, to work with "buffer" you can use a special C++ class - std::ostringstream.

std::ostringstream anOutputStream;
aWriter.WriteStream (anOutputStream);
std::string aRes = anOutputStream.str();

Unfortunately, you can't export/import GLTF to/from any buffers yet. Only file. If it is necessary, we can create a ticket to impliment ability to work RWMesh ToolKit (Gltf, Obj, Ply) with stream.

Best regards, Dmitrii.