So I have tried to create new terrain in HEC-RAS 5.0.3 using .img, .flt, and .tif files. All of them error out in step one: "Error creating Terrain: The system cannot find the file specified". Does anyone have a clue how to navigate through this? Is there some specific directory the initial files must be in? I have access to Erdas Imagine, WhiteBox, and ArcGIS (no 3-D analyst to convert to .tin). Any help would be greatly appreciated.