In this lesson, you show the apparent motion of the sun in the sky as the Earth moves from season to season.

Open SeasonsNP.max.

Select the Sun. In the Modifier panel, turn off the omni light.
Hide everything in the scene using the Hide Unselected command in the Display panel.
Render a single image of the scene, which should just show the Environment background of the starry sky

Save the image as StarrySky.bmp.
Then load the image into the Environment background, so that the stars won't move as you render the sun's apparent motion.

Unhide the Earth and the Sun.
Change the viewports back to the standard layout of Top, Front, Left and Perspective.
Make sure that the time slider is set to frame 0.

Click Zoom Extents All. The viewports zoom in on the Earth and Sun.

Open the Create panel and choose Sphere. Then enable AutoGrid:

In the Left viewport, create a small sphere by dragging on the Earth.
Name the sphere You Are Here and assign the sphere a red color.
Press M to open the Material Editor.
Assign the Red Circles material to the sphere so that is stands out against the Earth's surface:

Change views to the Right viewport.
In the Create panel, open the Camera sub-panel.
In the Right viewport, create a Target camera by clicking once in the viewport.
Name the camera You Are Here:

In the Top and Left viewports, move the camera so that it is aligned with You Are Here:

  

In the Front viewport, rotate the camerain Z so that it points downward, below the Sun. For an exact rotation, right-click on the Rotate tool and use the Rotate Transform Type-In dialog box:

In the Modify panel, drag the Lens spinner downward to its smallest size:

In the main toolbar, choose Select and Link.
Link the You Are Here object to the Earth.
Link the You Are Here camera to the You Are Here object:

    

In the You Are Here Camera viewport, you should just see the omni light that is the Sun:

Next, you need to compensate for the motion of the earth, which changes the camera angle relative to the sun.

Open the Time Configuration dialog box.
Click Re-scale Time.
Enter 1820 in either the End Time or Length (it doesn't matter which).

Close the Re-scale Time dialog box and the Time Configuration dialog box.
Now, when you render the sun, it will maintain the same horizontal position in the sky.

Open the Render dialog box.
In the Time Output group, choose Active Time Segment.
Then click Files.
Name the animation file SeasonsAM and choose the AVI file type.
Click OK and Close.

Save your file as SeasonsAM.max.

Render the scene. When you are done, view the file. The Sun flashes across the sky, first in an upward arc, then in a downward arc, or vice versa. Depending on where you placed your camera, the Sun may even disappear for a while. At the solstice it returns.

Save your scene file as SeasonsAM.max.

In the Display panel, click Unhide All. Change the viewports so that each one displays a different camera view.

Save your scene file as SeasonsAll.max.

Congratulations!

You have shown how the orbital mechanics of the Earth create day and night, the seasons, and the apparent motion of the sun in the sky throughout the year. On your own, figure out what else you can do with your model to learn more about the Nature's cycles.