I am basically looking for a software (free for students) to have mechanical 3D features (extrude, fillet, etc) and very basic animation capabilities (like different positions for a membrane to open an close a valve). It should be capable to export to other formats like jpg or pdf.
For example Autodesk 123Design is good but it does not export to any good format. I am not looking for something complicated like Maya and always have problems of putting lamps, lights, etc. Autodesk Inventor also looks very nice for designing but the rendering is not that straight forward. Any idea?