In this paper, we introduce approaches to sample chemical perception trees with both traditional atom types and SMIRNOFF fragment types. Here, we use the term chemical perception tree to describe a hierarchical classification of molecular substructures in order to assign parameters. One of our major interests is to sample over a variety of chemical perception trees to see if we can match the chemical perception used in existing force fields. We further use the term fragment type to refer to the more generalized notion of an "atom type" used by direct chemical perception -a particular substructure that would be assigned a particular parameter. The SMIRNOFF format, then, has four categories of fragment types -bond, angle, torsion, and nonbonded types -corresponding to the valence and nonbonded interaction force field parameters.