Duffell_Gap implements a one-dimensional model for generating synthetic gap profiles carved by planets in protoplanetary disks. The package includes C and Python reference implementations that compute density profiles in a disk perturbed by an embedded planet, with disk and planet parameters set directly in the model code. Users can compile and run the C version to generate output gap profiles and inspect the resulting disk structure, and adapt the Python version as starter code for further development. The software is intended as a straightforward base implementation of the gap model that can be modified for specialized studies of planet–disk interactions.