reference materialsMotion Mixer
 by Nathanael Fuller		  
   
Motion Mixer is a tool in Lightwave that allows you to create animations using non-linear techniques. You create a library of motions for an actor to use and place them into a timeline. An actor can be any Lightwave object including bones, cameras, and lights. Motions in the Motion Mixer timeline can be rearranged indefinitely, creating a more organic feel to an animation.



Figure 1a. Clicking the Edit Menu Layout… command.
   

Note: Before beginning this tutorial, you must load the Motion Mixer plug-in into the Lightwave interface. This can be done fairly quickly in a few steps:

1.) Click Layout > Interface > Edit Menu Layout... (Figure 1a)

2.) Find "MotionMixer" under "Plug-Ins" in the Command section of the window. (Figure 1b)

3.) Add "MotionMixer" into the menu in a useful location (ie. Under the Image Editor button).

4.) Click Done.

Figure 1b. Adding MotionMixer to the menu layout.
   
Motion Mixer Basics

1.) Download MotionMixer.lws and Hand.lwo (Alternatively, you can use the hand in the Lightwave stock objects. However, you will also have to add the bones in order to follow this tutorial).

2.) Load the MotionMixer.lws scene file. We now have a basic hand with a simple skeleton for the fingers in the scene.

3.) Click the MotionMixer button to bring
up the Motion Mixer window (This was placed below the Image Editor button for this tutorial). (Figure 2)

4.) Select the Hand object. Within the Motion Mixer window, click on Create Actor. Name this actor something simple like "Hand". (Figure 3)



Figure 2. The Motion Mixer window.




Figure 3. Naming the new actor.
5.) Open the Scene Editor window from the menu on the left. Select all the bones under the Hand object.
(Figure 4)

6.) Click on Add Items under the Actor Menu in the Motion Mixer window. Now it's time to get that hand moving!

7.) Rotate the Hand object 30 degrees on the Bank axis and create a keyframe at 60.

Figure 4. Selecting the bones in the Scene Editor.

8.) Click the Create Motion button in the Motion Mixer window. Name the motion "Hand_Bank" and make sure that the Actor Items button is highlighted. The Start and End Frames can remain at 0 and 60 respectively.
(Figure 5)

9.) Hand_Bank is now listed in the Motion List selection box. Click on the Add Motion button above the Motion Mixer timeline then click in the "00" track of the timeline.

Figure 5. Creating a new motion.
   
10.) Any motion in the Motion Mixer timeline can be scaled to different lengths. Do this now by dragging the end of the Hand_Bank motion to 30. You will notice if you scrub through the animation at this point, the hand resets to its original position after the end of the motion is reached. We need to tell the actor what to do after the motion is complete. (Figure 6)

11.) Right-click on the Hand_Bank motion in the timeline. Choose Add Post Behavior. If you have ever used the Graph Editor, then you are familiar with Post Behaviors. In Motion Mixer, the Constant behavior is the default. Since that is what we want, all you need to do is drag the end of the behavior out to 60. Now the hand stays where it moves. (Figure 6)



Figure 6. The Hand_Bank motionand a Constant post-behavior in the Motion Mixer timeline.
   
12.) It's time to create another motion for our actor. Rotate the Pitch channels of the three bones in the index finger of the hand until it is curled over almost touching the palm. Place all keyframes at 60. You will notice that we are placing the keyframes in the same place as the End Frame in the Create Motion dialog box. This is just to make things easier for this tutorial. Keyframes can be placed anywhere, and the End Frame can be defined for each motion that is created, if needed.
   

13.) Select the bones in the index finger and click on the Create Motion button. Name this motion "Index_Bend". This time, make sure to select the Selected Items button. This tells Lightwave to create the motion only from the selected bones rather than using the whole object. (Figure 7)


14.) Add this new motion to the timeline in the same way as the Hand_Bank motion, placing Index_Bend into the "01" track. Scale this motion to be 30 frames long and place the starting frame at 10.

15.) Add the Constant behavior to the end of the Index_Bend motion. Drag the end of the behavior to frame 60. You will notice that the finger does not bend completely at this point. That is okay...we will fix that in two different ways: transitions and the Channel Editor.

Figure 7. Creating the Index_Bend motion.
   

Transitions

1.) Select the Index_Bend motion.

2.) Click the Add Transition button above the Motion Mixer timeline Then click on the Hand_Bank motion.
(Figure 8)

3.) Now the finger bends down all the way. The transition combined the effects of both motions.

Figure 8. Adding a transition between Hand_Bank and Index_Bend.
Channel Editor

1.) Click the Channel Editor button above the Motion Mixer timeline.

2.) Select the Hand_Bank motion from the Timeline Motions menu.

3.) In the Motion Items menu, uncheck all the index bones from the list. Close the Channel Editor window. (Figure 9)

4.) The finger now bends all the way. We just told Lightwave that the Hand_Bank motion does not affect the bones in the index finger. This means that Index_Bend is the only motion acting on the index finger. When both motions were acting on it, the finger could only bend part of the way down. Using the Channel Editor is a good way to streamline the motions so that they only affect what you want them to.

Figure 9. Using the Channel Editor.
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