Restart Without Closing Programs?

I have a question that I have been unable to solve but first I will start off by saying I am running boot camp on a mac, just so there is no confusion. I am an architecture student and am using a program called Revit to render 3D models regularly. Due to the long render times find myself stuck waiting many hrs up to many days with my computer tied up rendering. Recently, after a lapse in smart thinking, my battery went dead and I thought I had lost 4 hrs of rendering time. I then disappointingly restarted my computer to restart the render but found that Windows had saved, as a last effort to maintain my program files and unsaved data, the progress of the render and it continued upon reboot.