This image shows a model of a real object. In AutoCAD, I had previously created views of the plastic portion of a hand-sized threaded knob. This made it easier to model this same knob in 3D.
While it is very easy to model a complex 3D object in Pro/ENGINEER, it is also possible (though not always, depending on the object) to model some objects in AutoCAD, although AutoCAD is tougher to work with in 3D and far less efficient. Of course, Pro/ENGINEER costs as much as a new car (or 5 of the computers you use to run Pro/E), so it only counts as a cheap rendering option if you already have access to it. Both packages make it easy to render views of an object once the model is created. For the Mac, DesignWorkshop Lite is freeware that can be used for 3D CAD and walkthroughs.
To capture a view of a 3D CAD object as it is shown in your working CAD window instead of a rendered view, just copy an image of (capture) the window to the clipboard (procedure varies with platform used, look under help in your operating system). Then paste into a raster image editor, crop out the unwanted stuff outside the object view, and save.