This tutorial is geared towards showing you how to use the Mental Ray renderer to create really good lighting and skies. First thing we need to do, before we begin, is set Mental Ray as the Rendering engine.
First, open Max then hit F10 to open the Render Scene Dialog. Then scroll to the bottom of the window until you find the Assign Renderer rollout, open it and hit the 3 little black dots button which in turn open the Choose Renderer window, in here chose the Mental Ray Renderer (Fig.01).
You can now close the Render Scene Dialog window. Next let's add our Sun; go to the Create Panel, then over to Systems, and in here create a Daylight system in the centre of your world, like so (Fig.02). Note: that the first thing you will create will be the compass and then the light will come out.
You'll notice that you can set the sun to be at particular positions based on the time of day. Play around with it. Once you're done, set your time back to the above settings.
Now we're going to change this light to use the power of Mental Ray: with the light selected, go to the Modify tab, change the Sunlight parameter from Standard to mr Sun and then do the same for the Skylight parameter to read mr Sky, as you can see in Fig.03.
Once you set the Skylight to mr Sky, you will get an announcement window asking if you want to add the Physical Sky map to the environment, just hit Yes. This is the map that will create our wonderful sky for us, so of course we want to add it!
Before we move on and test out what we have done so far, go ahead and create some objects in your scene so we can see how the lighting affects them. Make sure that you add a Plane for the ground - other than that, add whatever objects you like (Fig.04).
Now we have a few more settings to change before we can proceed. If you were to render now this is what you would see (Fig.05).
Everything is a little blown out so, we need some changes ... Go up to Rendering > Environment to open the Environment window. In here find the Exposure control rollout and make the following changes (Fig.06).
Now I'm going to rotate my perspective view so I can get a shot like this (Fig.07), and then hit Render.