link the various components of the mechanical arm into a hierarchy
that can be posed, you need to create a skeleton. A
skeleton is a hierarchy of joints that are connected together
In the scene, a joint
represents a special type of node that gets created in a skeleton
hierarchy. A joint acts as the parent node for any other joints
that occur in the hierarchy below it. Each joint has a rotational
pivot point associated with it. A bone is the visual representation
used in the scene view to connect the joints and help visualize
the joint chain.
A skeleton is similar
to a skeleton in the real world in that it acts as the underlying
structure for the surfaces to be attached. While you can view the
skeleton with its bones and joints in the scene view, it does not
appear in your rendered images. Its purpose is to assist you in
setting up and posing your models and characters and to visualize
the motion you want to achieve.
Skeletons are integral
to the animation of any character or hierarchical model. Examples
of characters that use skeletons are two and four legged animals.
Skeletons are also useful for animating other organic components
such as the tail of an animal, a tentacle of an octopus, or a snake.
In the following steps,
you create a simple skeleton consisting of four joints that you
combine with the mechanical arm model into a skeleton hierarchy, allowing
you to pose and animate the model.
create a skeleton for the mechanical arm
- In the perspective view menu, select Panels
> Orthographic > side.
The view updates to display
the side view.
You need to view the
components of the mechanical arm fully in the side view so you can
draw the joints for the skeleton.
- Resize the side view to a larger size
by dragging the border between the side and Hypergraph panel
- In the side view menu, select Shading
> Wireframe (Hotkey 4).
- From the main menu, select
Skeleton > Joint Tool > .
Settings window for the Joint Tool appears.
The Joint Tool is used to create
the joints and bones for a skeleton.
- In the Joint Tool settings
window, do the following:
- Click Reset Tool to
set the tool to its default settings.
- In the side view, starting from the base
of the mechanical arm, do the following:
- Click in the center of each pivot pin
on the mechanical arm to place four joints as shown in the image
Try to click as close
to the center of each pivot pin as you can, as the rotation of the
joints on the model will be based on the location of the joints on
the skeleton. As you place the joints, a bone appears, connecting
each joint. (Because the model lies along the YZ plane, the joints
are created close to the center of each corresponding joint on the
mechanical arm model.)
- After you place the fourth joint, press
Enter to indicate that the last joint has been placed.
- In the Hypergraph,
dolly the view to see the skeleton node hierarchy you just created.
(It appears at the right side of the view.)
- In the Hypergraph,
select the joint1 node.
The entire skeleton becomes
selected. Any rotations on this node also affect anything lower
down the hierarchy.
- Select joint2 (You can also press the
down arrow on your keyboard to select further down the hierarchy).
The skeleton is selected
from joint2 downwards in the hierarchy. Any rotations that you make
on this node affect only joint2 and nodes below joint2.
Once a skeletal hierarchy
is created, the various surface components can be added to the hierarchy.