 |
||
|
37.4 Cartoons - Leroy the Hawk, Animation 4 |
||
|
I do a 'Save Object As...', calling it 'Leroy_21.lwo'. MODELER, SIMPLIFIED STEPS... So, as I've shown in other tutorials, the first step is to create your object's complete skelegon tree while in the Modeler program, naming each skelegon properly. Next, still in the Modeler program, I create a weight map for each skelegon. And, also in Modeler, I ensure that the bank rotation handles are all properly aligned in Modeler (see the 'WHY ARE THEY [bank rotation handles] IMPORTANT?' section of Chapter 13.2). Next, I load the object into the Layout program, In the Layout program I Convert skelegons to bones by first selecting the object the bones are contained within, then doing an 'Items->Add->Bones->Convert Skelegons to Bones'. Also while in the Layout program, I set up my lights and camera, keyframing any rotations or movements I do to each light or the camera. Making sure that 'Auto Key' is turned on, I do an 'Items->Tools->Pivot->Record Pivot Rotation' on each skelegon to set each bone's bank rotation handle so it's correct for each newly-created bone. After recording the pivot rotations for each bone, I press 'r' to set their rest position. MODELER, LIMITING THE RANGE OF MOTION OF A SKELEGON There are those who limit the range of motion of the joints. If you bend your elbow, a limit is reached no matter what direction you turn where you can't move it past that point. When I bend my own right elbow towards my upper-arm, it's obvious that it's impossible that the wrist enter inside the confines of my body. When I extend my elbow straight, it can't bend too far past the straight-arm position. I've always found that, when using IK, limits make it feel like you've just run into a brick wall. However, for the beginner, you might find that limits help you keep limbs from moving into awkward positions. I won't delve deeply into how you set limits, as the use of limits tends to create unrealistic movement (particularly when using IK, which I tend to do a lot). MODELER, THE MOTION OPTIONS PANEL To set a bone's limits, while the object containing those bones is selected, I select  from the 'Items' Tab, 'Tools' section (or press the 'm' key).
It's very important that you've already recorded all pivot rotations for each converted bone by first having done 'Items->Tools->Pivot->Record Pivot Rotation' and set the rest positions before you set rotational limits. IMPORTANT - A word of caution for the advanced person... If you are going to reparent bones, the reparenting should be done BEFORE you record pivot rotations or strange things will occur when you use 'Parent in Place' MODELER, INVERSE KINEMATICS (Everybody shrinks back in fear...) That's a scary-sounding word sequence, and it tends to put people off because they think it'll be too difficult to learn. However, it really is quite simple. 'Kinematics describes motion or the study of motion. In LightWave, "You employ kinematics when you animate links of parented objects." You just got done learning how to make a series of parented objects, it was called a 'Skelegon Tree'. The 'Inverse' part of 'Inverse Kinematics' can be explained by visualizing a puppet. If I pull on a puppet's finger, his arm follows in a defined manner. If I push on the finger, his arm will retract and his elbow will bend, accomodating my pressure. If I roll the puppet's finger in a circle, his arm follows. The fact that I'm pulling on his finger to move his arm rather than him moving his arm by him moving his shoulder is the 'Inverse' aspect of 'Inverse Kinematics'. In the same manner, 'Forward Kinematics' would be if we could move the puppet's arm by moving his shoulder (the way we normally move our own arm). To keep from repeating myself I won't explain how to animate here. For more on using the Layout program for animating please see Chapter 41. |
||
