Game Development Reference
In-Depth Information
Step 7:
Assign eye vertices to respective joints. For the eyes, this is actually
a little simpler. Try this trick: Switch to Faces mode and double-click any of
the faces of the left eye. This will select out until it finds the edges of the
eyeball and go no further. Ctrl-right-click-hold and choose To Vertices and
then all the vertices of the eye will be selected. Again, in the Component
Editor enter 1 as the value for all the vertices under the AC_L_Eye column
(be sure to press Enter after entering 1).
Why?
There are actually a few interesting things happening here that should
be pointed out. Notice that when we selected the vertices and went
to the AC_L_Eye column, all the values were 0. They were 0 because in
the previous step they were part of the collection of vertices that were
assigned to the AC_Head_Base joint. A vertex's total weight value will be
1. So if more influence is defined to one joint, the vertex must rob that
influence from other places it may have been affiliated with. So when the
eye vertices were assigned to the head, it zeroed out the influence AC_L_
Eye had on it. Now that we've assigned all the influence to AC_L_Eye, the
influence that was on the head is gone (which is what should happen).
Step 8:
Repeat the process for the right eye, only assign the vertices to be
influenced 100 percent by the AC_R_Eye joint.
Step 9:
Use this same trick on the hip pistol and holster (assigned to
AC_R_Hip), the knife (assigned to AC_L_Knee), the backpack, and the rifle
(assigned to AC_Back_Small).
Why?
None of these objects should be bending. Other than the backpack, they
are all very rigid. By assigning them to any one joint, we'll ensure that they
won't tear away or bend when other surrounding joints are moved.
Painting Skin Weights
If you select AC_AegisChung_SM (the actual mesh) and look in the Channels
box, there will be a node called skinCluster1 in the Inputs. The skinCluster
node is actually the node that attaches the vertices to the joints, and it is part
of the mesh (
not
the joints). We have already looked at how to adjust this
skinCluster via the Component Editor, which works great for rigid parts of
the body.
However, most joints are much softer in their deformation. Most vertices on
the body need to lend their influence to a couple of joints at a time. Maya has
some fairly effective methods of allowing for this fine-tuning via very visual
workflows.
A note about skin weights first. We've already alluded to the idea that if a
vertex has a setting of 1 assigned to any one joint, its influence setting for all
