# Census Options

The Census options panel lets you configure which files Regina searches in the census lookup facility.

The census lookup facility allows you to select a 3-manifold triangulation and search for it within a list of ready-made census files. Through the settings here, you can add additional census files to this list, or disable the files that Regina uses by default.

Any additional files that you add must be Regina data files, but beyond this they do not need to be in any special format. When you perform a census lookup, Regina will simply search through every triangulation in all of the files listed here.

Instead of removing files, you can simply deactivate them. This means they will not be searched, but they will remain here in the list so that you can easily activate them again. Active files are marked with a tick, and deactivated files are marked with a no-entry sign.

You can never remove Regina's own prepackaged census files (these are the ones with plain English names, like Closed orientable census and Cusped hyperbolic census). However, you can still deactivate them if you do not wish to search them.