Non-Linear Animation: Animating with the Trax Editor in Maya 4.5 and 5

By Brian J. Immel

What is Non-Linear Animation?	Why use NLA	When not to use NLA	Build your animation first
Converting keyframes into Poses and Clips in the Trax Editor	Using the Poses and Clips in the Trax Editor	Modifying Clips	Layers of NLA
Advance NLA	The Big Show: Recreating a Slow Motion-Hyper Fast Animation Sequence	References and Resources

 

Using the Poses and Clips in the Trax Editor

1. After building a Pose or Clip, Maya will (by default) place a copy of the animation or pose data in a node that can be found in the Visor.

• Your data sets can be found under the following tabs depending on their type and usage:
  1. Character Clips
  2. Character Poses
  3. Unused Clips
  4. Unused Poses
• Sometimes it may be necessary to update or refresh the Visor when you create new poses and clips. To do this, just click on a different tab and go back to the one you were previously on.

2. Placing a Pose or Clip in the Trax Editor

• Middle Mouse (MM) drag and drop a Pose or Clip from the Visor to the Trax Editor.
• To reposition the Clip, click and drag the center of the clip to reposition it in time.
• Splitting and Merging Clips
  1. With the Trax Editor, you can introduce a pause or insert new animation data in between a motion sequence by simply splitting the Clip.
  2. To Split a Clip, move the time slider to the desired time and go to Edit > Split in the Trax Editor or by right clicking on the Clip and selecting Split Clip.
  3. To merge several clips into a single clip, select the clips you wish to merge and go to Edit > Merge.

Adding Tracks

1. Sometimes it becomes necessary to create additional track so that you can layer or blend animation together or to use the extra track as a temporary holding area for Clips that you are playing with.
2. To add a track, select the character track (little blue guy in the left corner of the Trax Editor), go to Modify > Add Track in the Trax Editor.

Looping

1. Grab the bottom right corner of a Clip and pull it out. The cursor will change into an arrow looping back into a vertical bar.
2. Maya will leave little tick marks to indicate the end of a loop. Using this method to make a repeating cycle is more memory effective than copy/pasting the same Clip again and again.

Scaling

1. You can change the length of time the Clip plays by scaling the length of the Clip.
2. Grab the top right corner of the Clip and pull it left or right. The cursor will change into a straight pointing arrow aimed at a vertical bar.
3. Pulling the Clip to the left will short the left of time thus making the animation data move faster. Pulling the Clip to the right will add more time to the Clip and make the motion move much slower.

Exercise: Scale, Split and Loop a Clip

1. Lets start with the Running_Clip. Open up the Oscar.mb file and import in the Running_Clip.ma file.
2. Open the Visor and MM drag-drop the Clip onto Oscar’s Character in the Trax Editor.
3. Loop the clip so that he runs in place three times.
4. Right-click on this looped clip and select Copy.
5. Add a new track.
6. Paste the copied clip into the new track. For the time being, disable the clip by right-click hold on the clip and uncheck the Enable option.
7. From the Visor, MM drag-drop the Clip behind the current looping clip.
8. Split the clip into thirds.
9. Move the last third away from the middle clip.
10. Scale the middle clip to a factor of seven or so.
11. Move the third clip so that it butts back up with the scaled clip.
12. In the second track, grab and move the second looping clip to the end of the split clips in the first track.
13. Right-click and enable the second looping clip.
14. Hit the playback button and watch as Oscar runs three times and then hits slow motion and goes back to normal speed. You may notice that the transition from the normal speed to the slo-mo is a bit harsh. You can blend the clips together so that the motion eases from normal time to slo-mo time.
15. Optional: to make a good blend between slo-mo and normal time, grab all the clips that are involved in the slo-mo sequence (all but the looping clips). Move them to the second track. Put about 4-5 frames between the beginning and end of the slo-mo sequence and the looping clips. Create blends with the beginning and ends of each clip that goes out of normal time into slo-mo and slo-mo to normal time.

Build a library of motions

• Re-usable motions (all character rigs) vs. proprietary motions (project specific).
• All Poses and Clips are stored in the Visor.
• Poses and Clips can be exported from this file and used in other scenes.