Graphics Programs Reference
In-Depth Information
Figure 9.33
The scale along the bottom of the window shows frames of the animation and the ver-
tical scale on the LHS shows displacement (how far the object moves). The displace-
ment from one frame to the next is always the same, hence constant velocity. There
is no acceleration or deceleration, as would be the case if you had used key frames.
Now, if you decide that you want to move in something other than a straight line, the
speed, acceleration, and direction of movement may have to be modified. The direction of
movement is modified by altering the shape of the path in the 3D window. The variation
in velocity and acceleration are altered in the graph editor window. We will first alter the
direction of movement by reshaping the curve path.
In the 3D window, select the path by right clicking on it, and then tab to put the path
into edit mode. Remember, in the beginning of this section we scaled the path to make it
longer while it was in object mode. You can do the same thing in edit mode. Just press the
S key and drag the mouse or, if you know how many times longer you want the path to be,
press the S key followed by a number key (use the number key at the top of the keyboard
not a number pad key).
Note that increasing the length of the path does not increase the length of the anima-
tion. You still have 100 frames in the animation; therefore, when running the animation
at 25 frames per second, your object will move along the path in 4 seconds. If you made
the path twice as long, the object would move on the screen twice as fast. Another way
to change the speed is to alter the number of frames in the animation in the properties
window - “Object Data” button - “Path Animation” tab. If you increase the number of
