Communicating with the help of images is powerful, but it often requires additional work, and that can be discouraging. ShapeOnYou for Mac can fulfill your need to add simple 3D shapes as support materials for your work. It is designed to be quick and easy to use and won't require any modeling to achieve satisfying but simple results.
ShapeOnYou for Mac consists of a 3D vector shape library that allows easy export to images. Those images can then be used in your text document as illustrations. The program itself already contains basic shapes and other examples that are of general interest. The main window lets you quickly drag the shapes around and position them the way you want. Coloring faces and parts of faces is also possible. Once the desired result is achieved, exporting a graphic image out of the 3D shape is done simply by dragging it outside of the window. Simple and easy. You can also paint the background and export the image in a rectangular shape. This program also allows the creation of simple animations. All you have to do is enter the transformations that you want applied to the camera. This feature wasn't easy to use at first but it's still functional for simple movements. Too bad importing from popular 3D formats such as SketchUp files in not supported, though you can drag and drop the results in other programs such as Keynote.
ShapeOnYou seems to be ideal for students as an aid for homework and reports that often need simple graphical 3D images.