This manual discusses the use and interface of the GibbsCAM 2.5D Solids option. 2.5D Solids is focused on the needs of machining 2.5D solids only. It allows users to define parts using solid and surface modeling techniques that can be directly machined using 2D, 2.5D and occasionally even 3D machining techniques. Recommended prior reading: Geometry Creation,; Mill,; Advanced CS. Last major update: April 2009, for GibbsCAM 2009, v9.3; minor revisions January 2015, for GibbsCAM 2015, v11.0