When teachers first wrap their heads around scientific modeling, it can be a bit tricky to distinguish scientific models from diagrams and three-dimensional models. If a fifth grader draws and labels a food web, it's a model. Right? Not necessarily. When creating a model, students should be representing a system inspired by an inquiry or phenomenon. Because models represent "their" current understanding, students' models will differ from each other. Additionally, the models will change throughout the unit of study as student conceptual understanding matures. This article describes how one teacher created a three-dimensional rubric to assess students' digital models--a way to assess students' conceptual understanding and their progress on the components of modeling, as well as connection to the crosscutting concepts. The article describes a digital modeling activity that students completed and then explores ways to use the rubric to assess their understanding.