3D Rigging Technique in Animation
3D rigging is the process of creating a moving skeleton for a 3D model. The character is rigging before they are animated because if a character model doesn’t have a rig, they can’t be deformed and moved around. When you apply a rigging technique, you add in joints, all of which are connected by bones. They are stuck in whichever pose the modeler decided to put them in.
The rigging process can become entirely technical and seem overwhelming at times, but after a little practice, you will be creating great rigs in no time.
The process of rigging is we take that digital sculpture, and we start building the skeleton, the muscles and then attach the skin to the character, and we also create a set of animation controls, which our animators use to push and pull the body around.
Click on below Link: Rigging Process
3D Rigging Technique Terms You Need to Know
You can think of joints for rigging in the same way you think of joints in a human body. They work in the same way. Joints are the points of articulation you create to control the model. In case, if you were to rig a character’s arm, you would want to place a joint for the upper arm, joint for the elbow and joint for the wrist, which allows the animator to rotate the arm realistically.
Click on below video: Skeleton 3D Model
2. Driven Keys
A rigging artist can utilize driven keys when applying rigging character. Driven keys allow you to use one control or object to drive the multiple different attributes and object.
In above example, we can use a driven key to control the first position for the hand, with just one single control. A driven key contains two parts: the driver and the driven.
The driver is the object which controls animation. The driven is the objects and attributes that are being controlled by the driver. Typically for the regular key frames, an attribute has values keyed to time in the time slider. For a driven key, the attribute has values keyed to the value of the driving attributes. The driver can be another object, or in the case of the example image above it is a control slider.
3. Blend Shapes
A blend shape or morph depending on the 3D application, allows you to change the shape of one object to another. When rigging use for blend shapes is to set up poses for facial animation. It might be lip sync poses or complex expressions like a frown or smile. You can join all these new poses into the original face mesh and have it operate all in one control slider.
4. IK (Inverse Kinematics)
Inverse Kinematics means that the child node within your rig’s hierarchy can affect the movement of its parents.
Example: If you use inverse kinematics for your character’s arm you can position your character’s hand, and the rest of the arm chain will be calculated. It allows the animator to animate independently of the chain’s hierarchy. Because of IK is great when needing to have a character’s arm stay planted on something.
Click on below video: Difference between FK and IK
5. FK (Forward Kinematics)
In this Forward Kinematics, your character rig will follow the hierarchal chain. That means more control over your chain, but also means you don’t need to position each joint in your chain independently of each other.
Example: With FK if you positioned the character’s hand the rest of the arm wouldn’t follow as it does with IK. Instead, you need to position each joint independently, starting with the upper arm, the elbow and then the wrist. It takes more time than IK but can give the animator much more control of the poses. Most times riggers will incorporate both IK and FK into the rig to meet the animator’s needs.
6. Control Curves
In rigging technique, Control curves are created by the rigger to assist the animator in manipulating joints within the rig. Typically a rig consists of many elements that need to be managed to move the character in the desired pose. It can be very difficult to do without control curves because the animator would need to hide the mesh to see the skeleton within the character and try to determine which joint manipulates the elbow.
Example: Control curves are typically simple NURBS (Non-uniform rational B-spline) curves placed outside of the character so the animator can easily select the curve to position the character instead of the actual joint.
Click on below video: Creating Skeleton for Character Animation
7. Constraint Constraints
This is very important in both the rigging and animation process. Typically your 3D application will have several options for constraining. Constraints limit an object’s position, rotation and scale based off of the attributes of the parent object.
Click on below video: Basic Setup of Parent Constraint
Many different deformers/modifiers are depending on the 3D application which can be utilized to enhance your rigs. Deformers are often used among modelers, but they are also beneficial for riggers as well. Deformers contain the algorithm that can move the large sections of vertices on a model to produce organic shapes.
Skinning is the process of taking the bones or joints of the rig and binding them to the actual 3D mesh. When the joints are bound to the 3D mesh, it allows you to move the joints, and the mesh will follow. Without skinning the mesh to the joints will not influence the actual 3D model.
10. Weight Painting
Weight painting is a vital step once the skeleton has been created. Even though the bones are put in place, it doesn’t mean the 3D model will be able to deform perfectly how you want. When a mesh is bound to the skeleton, the computer doesn’t know how much control the each joint should have over each vertex, so it averages the weight out based on the distance from joint to the mesh. Basically painting weights allows you to set how much influence a joint has on a specified area of the model and correct the deformations on the 3D mesh.
Click on below link: Rigging and Weight Painting in Blender
11. Facial Rigging
When creating the complex character rigs, the facial rig setup is often a whole different monster. A typical joint or bone setup doesn’t work well for a facial rig other than having joint for a jaw bone because facial movement often requires stretchy and organic motion. Instead of a normal joint setup, facial rigging usually requires deformers and blend shapes which were discussed earlier.
Keep learning with creative professionals how to use these terms and develop rigging technique through hands-on experience.
But to learn this rigging technique in depth one should join our animation training institute. It is one of the best institutes in Ahmedabad which imparts advanced animation courses.