I have some bathymetry data in TIN format; I am able to open this in arcmap and view the terrain. However I need to use this data within a simulation framework called Delft3D, which needs the bathymetry data in ascii format (.dep). I am very new to both of these software technologies, I wanted to know how I can convert the TIN format data to a .xyz file or even a .dep file using arcgis or even something external.
If you have access to the 3D Analyst extension, this can be accomplished using the TIN Node tool found here: 3D Analyst Tools - Conversion - From TIN - TIN Node. This will create 3D points (i.e Z-enabled) at each triangle node that forms the TIN. Alternatively you could convert your TIN to a raster, and then use the Raster to Multipoint tool which will create points at each raster cell center (as opposed to the TIN nodes). This approach will give you more flexibility regarding the number of output points, as it will be based on the raster resolution which you can modify to fit your needs.
Once you have your point file, you can use the Feature Class Z to ASCII to get your desired output format.