Game Development Reference
In-Depth Information
Joint Cleanup
The principal skeletons for Kila and Grae are now complete, so let's find out how many
joints make up each one. In this case, I have made this easy for you; the number of joints
in the scene does not match the number that will be used in the game. All of the end joints
are there merely as a visual aid; the actual geometry will not use them to move.
Note
You'll want to double-check this with the relevant programmer; it may be
that your game engine does need these end joints.
Contained in the GCDM shelf is a button labeled jntCnt. Running this will give you an ac-
curate joint count. It will not, however, include any of the end joints (such as the eyes), so
you will have to add these to the count.
Using the jntCnt tool, we can see that Kila uses 57 joints, plus another 4 for her eyes and
chest, bringing the count up to 61. Grae uses 66, plus 2 for his eyes, making the total 68.
Inthenextsection,wewillneedtocheckhowtheskeletonwillmove—or,moreaccurately,
rotate.
Depending on how you constructed the skeleton, there may be some values in the rotation
attributes. Because the majority of the skeleton is controlled by its rotations, it's vital that
these are zeroed out before checking the rotational axes. Having them all at zero will sim-
plify animation and control.
Before we continue to the next task, quickly select all the joints and freeze the transforms,
making sure to freeze only the rotations.
Checking the Rotational Axis
One of the most important stages in character rigging, particularly in Maya, is to check the
rotational axes. The way a joint rotates depends on how the axis is aligned. This is particu-
larly important when you are using joint chains as we have done in Kila and Grae.
Look at
Figure 11.23
,
left. Here we have our current hand for Kila, which looks fine. To
get the fingers to bend and make a fist, we would select the root of each finger, then its
hierarchy, and do a global rotation around the Z axis.
Figure 11.23
,
right, shows the result.
Because all of the rotational axes are out of line at this point, the fingers are all bending in
random directions.
