  We present RadFil, a publicly available Python package that gives users full
control over how to build and fit radial density profiles for interstellar
filaments. RadFil builds filament profiles by taking radial cuts across the
spine of a filament, thereby preserving the radial structure of the filament
across its entire length. Pre-existing spines can be inputted directly into
RadFil, or can be computed using the FilFinder package as part of the RadFil
workflow. We provide Gaussian and Plummer built-in fitting functions, in
addition to a background subtraction estimator, which can be fit to the entire
ensemble of radial cuts or an average radial profile for the filament. Users
can tweak parameters like the radial cut sampling interval, the background
subtraction estimation radii, and the Gaussian/Plummer fitting radii. As a
result, RadFil can provide treatment of how the resulting filament properties
rely on systematics in the building and fitting process. We walk through the
typical RadFil workflow and compare our results to those from an independent
radial density profile code obtained using the same data; we find that our
results are entirely consistent. RadFil is open source and available on GitHub.
We also provide a complete working tutorial of the code available as a Jupyter
notebook which users can download and run themselves.
