Trim Mesh is an Edit mode tool for modifying geometry based on the normals of selected vertices, edges, or faces. Accessed through the right-click context menu, the add-on cuts away geometry along the selected component's normal vector. Users can adjust the tilt angle and direction to refine the cut plane. It also includes a slice mode that creates cuts without removing geometry, functioning similarly to a directional loop cut. The tool is particularly useful for modifying convex areas without affecting surrounding topology.