So, the first recipe of this chapter is about the making of the Armature by hands for our Gidiosaurus.
In this first recipe, we are going to build by hands the basic rig, which is the skeleton made only by the deforming bones.
However, first, let's prepare a bit the file to be worked:
Gidiosaurus_unwrap_final.blend
file.Gidiosaurus_rig_from_scratch_start.blend
.Let's start:
So, now we have built the spine - neck – head part of the Armature; actually, one thing is still missing: the bone to animate the mandible.
At this point, we can already see some particular setting to be applied to the bones.
In the preceding screenshots, you can see that we have hidden the talons vertices in Edit Mode (H key), in order to have the possibility to easily select the last edge-loops on fingers and toes.
Gidiosaurus_rig_from_scratch_01.blend
.Now that we have completed the main body rigging system, it's time to build the rig for eyes, eyelids, and tongue:
At this point, the basic rig building process is almost done, even if it is only for the left-half part of the mesh:
As a very last thing for this recipe, we must verify that the alignment of the bones, especially the last duplicated ones, is correct and, just in case, recalculate the roll rotation, that is, the rotation around the y axis of the bone itself.
By the way, it is good practice to not trust this automated procedure alone, because sometimes it can give inconsistent results; so, do the following:
By enabling the X-Axis Mirror item in the Armature Options tab under the Tool Shelf, you can recalculate only the bones of one side; the other side bones will follow automatically.
If you want to make sure the bones' orientations are correct and everything is going to work in animation, just go into Pose Mode and rotate one bone, for example leg.L, and then click on the Copies the current pose of the selected bones to copy/paste buffer button (Ctrl + C), which is the first left one of the last three buttons to the right-hand side of the viewport toolbar; then, select the symmetrical bone, leg.R, and click on the last right button to paste the flipped pose (Ctrl + Shift + V); if the leg.R bone rotates correctly, then the orientation is OK:
In the following screenshot, all the eight B-bones have been selected to make them more visible. By the way, the highlighted leg.R bone is the active one and shows the Curved Bones setting in the highlighted Deform subpanel to the right-hand side of the screen.
Although it's often a really time consuming task, the handmade rigging is quite self-explicative; it is, however, better to explain some of the concepts behind this.
The proper renaming of the bones is important, considering that each deforming bone will affect a vertex group sharing the same name on the mesh; although in some cases, as for the tongue bones, the bone naming process can be automated in some way, usually it is better to spend time in giving meaningful names to each bone, in order to avoid mistakes in the following skinning process.
It's also very important to build the hierarchy of the bones so that a bone at a higher level can lead all of the children bones, as it would be in a real skeleton (that is, for example, the hand bone leads all the fingers bones, the forearm bone leads the hand bone, and so on).
Parenting a bone and then obtaining the others by extruding and/or duplicating simplifies the work because an extruded bone is automatically parented to the bone it has been extruded from, and a duplicated bone obviously inherits the parenting of the original one; in the case of the tongue.001 bone, extruding the others has given us a chain with bones automatically parented and named as tongue.002, tongue.003, tongue.004, and tongue.005.
B-bones are both a visualization mode for the bones and a way of working; B-bones, in fact, can work inside a chain as splines, which means that the bones are curved according to the number of Segments and the values of the Ease In and Ease Out items. For the bones of the arms and legs, we have set the Ease In and Ease Out values to 0.000 (default is 1.000; maximum is 2.000), in order to have the B-bones rotating only on their y axis but remaining straight along their length, and hence, mimic the twisting by not only the rotation (pronation and supination of the lower arm) of both the Ulna-Radius and Tibia-Fibula articulation complexes, but also the (limited) rotation of Femur and Humerus.
In some way, B-bones can work as a kind of simulation for a very basic muscle system; in the following screenshot, you can see their effect on the skinned mesh for the forearm by rotating the hand.L bone on the local y axis (to enhance the visibility of the mesh surface's modifications, the wireframe over solid drawing item has been enabled in the Display subpanel under the Object window):
Here is the effect of the rotation of the forearm.L bone on the Gidiosaurus high arm:
The effect acts on the shin as well, by rotating the foot.L bone on the global z axis:
Also, the same effect acts on the thigh by rotating the calf.L bone:
Note that the Gidiosaurus is a digitigrade biped humanoid: the bones that, from our plantigrade point of view, look like the foot are actually the toes, while the almost vertical structure that we would call an ankle is the real foot (this is a very common condition among the majority of the terrestrial animals, both still alive and extinct).
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