Under each material node, you can create new material groups of the same type/category but with different properties (color, texture, or electric and magnetic constitutive [[parameters]]). These material groups are used to organize the CAD objects you draw in the project workspace or import from external model files. When you create a new geometrical object such as a Box or a Sphere, it is inserted under the currently active material type. There is only one material group that is active at any time. It is recommended that you first create material groups, and then draw new objects under the active material group. However, if you start a new EM.Tempo project from scratch, and start drawing a new object without having previously defined any material groups, a new default PEC group is created and added to the navigation tree to hold your new CAD object.
[[Image:MORE.png|40px]] Click here to learn more about the various '''[[FDTD Material Types]]'''.
===Defining a New Material Group===