In this lesson, you'll bring the battlefield scene to life by animating scene objects.

You'll do this with keyframe animation. The Auto Key tool in 3ds Max lets you record the physical characteristics of an object at any given point in time. This state in time is called a keyframe. 3ds Max then figures out all the in-between states from one keyframe to the next, for a smooth transition of the object.

The following procedure consists of two animations. Between frames 0 to 120, you will advance the cannon to its firing position, next to the rock. Between frames 120 and frame 160, you will raise the cannon barrel in preparation for the first shot.

3ds Max gives you three different ways to create keyframes. One is to turn on the Auto Key button, move to any point in time, and transform (move, rotate, or scale) the object. A second method is to right-click the time slider and then set keys using the Create Key dialog. There is also a Set Key animation mode, designed for professional character animators.

In this exercise, you’ll use the Auto Key button.

Set up the scene:

• Continue with your own scene, or open battlefield_scene.max.

Animate the position of the cannon:

1. Right-click the Top viewport to make it active, then zoom in and pan the scene so that the cannon and rock are clearly in view.
2. On the main toolbar, click (Select And Move), then hover your mouse over the rear portion of the cannon.

   After a moment, a tooltip appears that says frame.

   The tooltip indicates your selection tool is hovering over the frame object. In this scene, frame is the parent object of the cannon, meaning that if it moves, the rest of the cannon assembly moves with it.

   
3. Click the frame object to select it.
4. The time slider is the wide button located directly above the time scale display below the viewports. Drag the time slider to frame 120 (to create a 4-second animation when played back at 30 frames a second).
   
5. Click (Auto Key) to turn it on.
   

   The button turns red. You are now in automatic animation mode.

   
   Tip The time slider bar also turns red, and the active viewport is outlined in red to remind you that you are in Auto Key mode.
6. In the Top viewport, select the frame object and drag it on its Y axis until the cannon is lined up next to the rock.

   Autokey interpolates, or averages out, the cannon position at each frame from its start position at frame 0 to its final resting place at frame 120.

7. Turn off (Auto Key).
   TipTo avoid accidentally creating unwanted animation, develop the habit of turning Auto Key off after animating each movement.
8. Move the time slider back and forth from frame 0 to frame 120, and watch the cannon move forward.

   Notice how animation has already been applied to the windmill in the background.

Add a second animated movement:

1. Turn on (Auto Key) and advance to frame 160.
2. Press H on the keyboard.

   3ds Max opens the Select From Scene dialog.

3. In the list of objects, choose barrel, and click OK.
   

   You might have to scroll, or resize the Select From Scene dialog, in order to find the barrel entry. If the frame object has a plus-sign icon in front of it, then the Select From Scene dialog is set to display the object hierarchy: Click the plus-sign so you can see the children of frame, click to highlight barrel, then click OK.

   
4. On the main toolbar, click (Select And Rotate).
5. In the Camera viewport, rotate the barrel on its X axis by –10 degrees.
   

   As you modify the barrel rotation, the axis values update in yellow.

6. Drag the start keyframe at frame 0 to frame 130.
7. Turn off (Auto Key).
8. In the animation playback controls, click (Go To Start), then click (Play Animation).

   Watch the animated cannon prepare its deadly attack on the windmill.

9. Click (Stop, in the same location as the Play button) when you are done watching the animation.
10. Save your scene to your local folder, this time as my_battlefield_attack.max.