Project project = new Project("New Project.mpp");

// Define the SaveOptions with required TimeScale settings as Days
SaveOptions options = new PdfSaveOptions();
options.Timescale = Timescale.Days;

// Set the Presentation format to ResourceUsage
options.PresentationFormat = PresentationFormat.TaskUsage;

project.Save("TaskUsageView_result_days_out.pdf", options);

// Set the Timescale settings to ThirdsOfMonths
options.Timescale = Timescale.ThirdsOfMonths;

project.Save("TaskUsageView_result_thirdsOfMonths_out.pdf", options);

// Set the Timescale settings to Months
options.Timescale = Timescale.Months;

project.Save("TaskUsageView_result_months_out.pdf", options);