The executive summary, for people who have a clue what they're doing:

  1. Download the latest version of the script from the main page.
  2. Download "GMaxSLGRAB", found here. It is a simple binary that will grab the full text buffer from the maxscript listener and save it to a file of your choosing. If the above link is dead you can also get the tool here.
  3. Install Yafray: http://yafray.org
  4. Open up gmax, and drop the yafray-material.ms script into your scripts/startup folder wherever gmax is installed. You can put the Yafray-Export script there too if you want. Start up gmax. The interface is accessible in the Utilities panel.
  5. Load up your scene. You need at least one camera and one light to be able to see anything that gets rendered. All objects need a material applied to them as well. No material, nothing gets rendered. I reccomend using the yafray material I created because it uses yafray terminology and supports the yafray features better. Standard material types still export just fine however.
  6. Open up the MAXScript Listener window.
  7. Switch to a viewport of the camera you set up, and hit export. Things should get busy in the listener.
  8. Start up GMaxSLGrab if you haven't already, and press the big GRAB button. This will save the file.
  9. At a command prompt, navigate to wherever you installed Yafray, and run the program giving the XML file you saved as an argument.
  10. Stuff happens, your scene gets redered. When finished a file called gmax_render.tga will appear, containing a rendered version of your lovingly sculpted model.

Longer Version, for you Newbies