We ran into a problematic CAD file recently. Importing the model with Exchange was successful and the model rendered and worked correctly. We later serialized the loaded model to a byte array for embedding in our application file (via A3DAsmModelFileExportToPrcStream). When later loading the file and de-serializing the byte array back to a model file (via A3DAsmModelFileLoadFromPrcStream) it seemed to work and returned a non-null model file pointer, however when attempting to render the model in Visualize the app crashed.
A deeper look showed that the serialized byte array for the model was only ~200 bytes. So clearly the serialize didn’t work and when de-serializing we ended up with a non-valid but not-null model file pointer.
We’ve updated our code so that now, after de-serializing, we validate the model file. If this fails, we mark the CAD as invalid in the tree. This is probably a good check to do in general when receiving a model file pointer, before attempting to use it. The below is C++/CLI called from C# to do the check.
static bool IsValidModelFile(IntPtr modelFilePtr)
{
if (modelFilePtr == IntPtr::Zero)
return false;
auto mfp = modelFilePtr.ToPointer();
A3DAsmModelFileData modelFileData;
A3D_INITIALIZE_A3DAsmModelFileData(modelFileData);
auto iRet = A3DAsmModelFileGet(mfp, &modelFileData);
if (iRet != A3D_SUCCESS)
return false;
A3DAsmModelFileGet(nullptr, &modelFileData);
return true;
}
