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It’s possible to have multiple different units used inside of a same model, so that’s why the ModelFile and each ProductOccurrence can have its own unit (see both A3DAsmModelFileData::m_dUnit and A3DAsmProductOccurrenceData::m_dUnit).
In order to find the one global to the whole model, you’ll need to browse through its modelFile and sub-POs and find the first one for which m_bUnitFromCAD is set to true.
That’s basically what the function A3DAsmModelFileGetUnit (introduced since HE 2019) does.
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Be careful because the model unit found may look slightly different from what is rendered if a scale is also set inside of the A3DTopoContextData. |
How can I overwrite units inside of a PRC file ?
The easiest and fastest way to proceed is to create a new modelFile (with the A3DAsmModelFileCreate function) or to edit the root PO (you can use A3DAsmProductOccurrenceEdit for example), by setting m_bUnitFromCAD to true and put the desired m_dUnit (defined as a mm multiple).
Please find below a code sample as an example:
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A3DAsmModelFileData sNewMFData;
A3D_INITIALIZE_DATA(A3DAsmModelFileData, sNewMFData);
sNewMFData.m_uiPOccurrencesSize = 1;
sNewMFData.m_ppPOccurrences = new A3DAsmProductOccurrence*[1];
sNewMFData.m_ppPOccurrences[0] = pRootPO;
sNewMFData.m_bUnitFromCAD = TRUE;
sNewMFData.m_dUnit = dDstUnit;
iRet = A3DAsmModelFileCreate(&sNewMFData, ppModelFile); |