3D modeling
Are you using AutoCAD Architecture 2013 or AutoCAD 2013? If AutoCAD Architecture, are you looking for the Solids and Surface tools (rather than the AEC object tools, which are, mostly, also 3D)? I do not have access to 2013 any longer, but I believe the ribbon setup is similar to later releases. Try right clicking on the ribbon, and then selecting Show Tabs > on the context menu. The flyout menu will list all of the ribbon tabs available in the current Workspace. Those with a check mark in front are already turned on; you can select any of the ones without a check mark to turn it on. As shown in the image below, the ACA.cuix customization file does include ribbons for AutoCAD Solids (3D) and Surfaces tools. Is that what you seek?
