When I was first looking for a 3D design program several years ago, most of them were very expensive and complicated (far too complicated when I just wanted to use them for print work and packaging visuals).There are now several free 3D options available a couple of which I downloaded to try out.
Google Sketch Up
I had heard of google sketch up but to be honest didn’t really know what it was – the name makes it sound more of a drawing /design program rather than 3D software. What I like about Google Sketch up is that it is fairly intuitive. You click on a tool and a box with al the information about what that tool does and how to use it appears, which is pretty useful when you are trying to learn. You can easily make 3 dimensional squared objects by drawing lines in 3 dimensional space and extruding. You can also create lathe objects – although this is a bit less obvious using a a feature called follow me. Drawing curved lines is not as simple as straight, there is an arc feature but it is not easy to control, a bezier drawing tool would make a great addition. Available for Mac and PC.
Below is a very simple tutorial from Youtube showing how you can build simple objects in Google Sketch up very easily. There are several more video you can find with more complex examples on Youtube too
Art of Illusion
Art of Illusion is an opensource 3D modelling and rendering program. I only quickly took a look at this program but I liked how simple the interface is unlike a lot of commercial applications. It looks like this program would be much better for organic forms than Google SketchUp with the use of Triangular meshes. There is also a online/download manual and tutorials available. This is definitely one worth taking a look at if you want a free 3D program. Available for Mac, PC and Linux