Swap Low Res with High Res icon button (available only when Preprocess Large Data Files is complete and a set of component objects resides in the Model Manager) - swaps a low-res object in the Model Manager with a corresponding high-res object in the Project Directory, or a high-res object in the Model Manager for a corresponding low-res object in the Project Directory.
All objects that are selected in the Model Manager are subject to the swap. Objects that are not selected in the Model Manager are not subject to the swap.
To verify that the correct Project Directory is being used, go to Settings.