One of the basic animation methods are key framing. This is used in both traditional and digital animation whereas the strong characteristic poses are drawn out or transitioned and the "tweeners" or a computer create the frames of animation between key frames.
Another important consideration is that gravity doesn't affect the ball equally at all points in the balls travel. The ball will rush towards the ground, strike quickly and bource upward. When the goes travels upwards it will slow down in it's upward movement and then accerate again towards the ground. By using Carrara 5 Pro's Graph Editor, we will be adjusting the automatic tweening between key frames. In figure 1 below, an illustration helps to clarify the travel path we will be creating.
Figure 1.
In addition to key framing another important animation characteristic is squash and stretch. This will be clearly seen in this tutorial when the ball hits the floor and when it soars upwards & falls downward. In figure 2, an illustration of the general effect a ball has when being pulled by gravity and hitting a surface can be seen.
Figure 2.
Because this tutorial is about the key framing aspects and the use of the graph editor, a begining scene file is supplied below. The floor and ball has been made for you as well as two morph targets for that ball for both the squash and stretch.
1. Unzip the above file and open the file within Carrara 5 Beta. You will notice several things. There are 3 lights, an infinite (ground) plane, a vertex modeled ball and a camera in the scene. The ground and camera has locked constraints placed upon them so they will not be able to be moved by accident. Your scene should like like Figure 3 after opening it.
Figure 3.
2. Move the timeline's "adjustment triangle" for the frame while watching the frame's counter. Move the adjustment triangle to frame 17. Then move the ball forward some followed by lowering the ball until the bottom slightly goes through the floor. Your scene should look like Figure 4.
Figure 4.
3. Move the adjustment triangle to frame number: 1.07 (1 second and 7 frames; ie. the 31st frame). Move the ball about 3/5th the height it was in Frame 1, then move to a little less than the distance that was moved from frame 1 to frame 17.
4. Move the adjustment triangle to frame number: 1.19. Move the ball more forward, then move the ball so that it is only slightly under the ground plane.
5. Goto frame 2.04. Move the ball a little forward and upwards.
6. Goto frame 2.12. Move the ball forward a little bit and downward so it just touches the surface of the ground plane. Normally, we would continue with this action until we determined that the ball has lost enough inerta to continue moving or another force is being acted upon it. However, for the purposes of this tutorial, the prior sequence will suffice. Figure 5 displays what your timeline should look like.
Figure 5.
7. Carrara defaults to a 4 second animation length. We will change this by adjusting the right, yellow, half triangle at the 4 second mark. Move this triangle to the frame number 2.12.
To test out the animation, press the loop button followed by the play button. When you are done testing the animation, press the stop button and move the timeline's adjustment triangle to frame 17 (the location of the first key-frame).
8. In the timeline, click on the little triangle next to the "Red Ball" object. This will expande the object's characteristics and display where exactly the key frames have been placed. Then expand the following items in this order: Transform then Position. Your Timeline should look like Figure 6.
Figure 6.
9. Click on the word "Positions" from the timeline. This will highlight that item and the three sub-elements. Then click on the "Switch Timeline / Graph Editor" button. The timeline area will change appearance into the graph editor. You Figure should look similar to Figure 7, however, do not worry if the wave pattern doesn't match up exactly.
Figure 7.
You will notice that each line has a different color and that the colors match your settings for the x-axis, y-axis and z-axis. In the above figure, you may notice the following characteristics about this animation:
10. Click on the blue line's first node at frame number 1. Then click on the flat tangents button. You should see a single handle appear to the rightside of the node and that the line segment between the frame 1 and frame 17 is slightly curved now. Adjust the handle so that there is a steep drop to the next node.
11. Repeat step 10 with the nodes on frames: 1:07 and 2:04. Your graph editor may look something like Figure 8.
Figure 8.
Currently, we have finished with the animation movement and adjusting the weight of the tweening. We will now use the morph targets that was made on the Red Ball object to deform it when it hits the surface of the ground. Click on the Switch Timeline / Graph Editor button to return to the timeline view.
12. Select the Red Ball object and enter the vertex modeler. Move the timeline's adjustment triangle to frame 17. Click on the Morph tab in the properties panel. Then slide the morph target, squash, to the far right (value 1.0). The morph target properties area should look like Figure 9.
Figure 9.
13. Continuing with a similar pattern as in step 12, enter set the following morph target keyframes (Step 12's frame 17 was added to this list as a reference, but you will need to add the stretch value (of "0") to that frame):
NOTE: The easiest way to set a morph target setting that is the same as the prior keyframe's value is to "wiggle" the slider and return to the same value. You will need to do this numerous times to use the below chart.
| Frame Number | Squash Value | Stretch Value |
|---|---|---|
| 0:16 | 0 | 0.65 |
| 17 | 1 | 0 |
| 1:07 | 0 | 0 |
| 1:18 | 0 | 0.15 |
| 1:19 | 0.60 | 0 |
| 2:04 | 0 | 0 |
| 2:11 | 0 | 0.08 |
| 2:12 | 0.33 | 0 |
After you are finished with the morph target assignment, you can review your work in the timeline. In Figure 10, you can clearly see where each keyframe is applied and to which morph target it is applied to. This can be an easy way to spot a missing keyframe before entering into the next step of this tutorial.
Figure 10.
14. Select the "All Ball" morph target area in the timeline. Then click on the Switch Timeline / Graph Editor button. In Figure 11, you will see what the graph representation of the morph targets look like.
Note: Seen below is the graph for both morph targets. If you prefer to work with only one morph target at a time, you can select the name of that specific target instead of the morph area name.
Figure 11.
15. We will adjust the morph target acceration (the Stretch target) before it hits the ground first. We do this in a similar fashion to what we did with the Red Ball's position earlier.
Select the first node (the node above the other on frame 0:16) and then apply the Toggle Left Tangent button. Adjust the handle so that it points underneath and close to the bottom node.
Repeat the above paragraph for the other two relevant keyframes (on 1:18 and 2:11). Your graph should look something like Figure 12.
Figure 12.
16. In a similar fashion to what we just did with the stretch graph, we will now address the squash graph.
Select the top node on frame 0:17, and press the Toggle Right Tangent button. Adjust the handle that appears so this is is just above the bottom node.
Repeat the above paragraph for the frame 1:19. Your graph should look something like Figure 13.
Figure 13.
At this point in the tutorial, you are done. You can now go back to the Assembly room for your own tweeks and review of the animation or go to the render room and render this scene out.
The below file is a zipped ".car" version of the my completed tutorial.
Click on the below image to view the ballBounce animation in Quicktime format (with Sorenson 3 compression).
Click the image to view the Quicktime movie-clip of this animation. (452 KB)
