You can set a standard paper size (like A4) by selecting it from the predefined list using OdDbPlotSettingsValidator object: ::odrxDynamicLinker()->loadModule(OdPlotSettingsValidatorModuleName); OdDbPlotSettingsValidatorPtr pPlotValidator = svcs->plotSettingsValidator();
OdResult res = pPlotValidator->setPlotCfgName(pPlotSettings, "DWG To PDF.pc3");
res = pPlotValidator->setCanonicalMediaName(pPlotSettings, OD_T("ISO_A4_(297.00_x_210.00_MM)"));
You can see other methods of setting paper size for PDF export in our documentation: https://docs.opendesign.com/td/export_to_pdf_03parameters_flags_paper_size.html