Skeletal animation is a technique in computer animation where characters (or other articulated objects) are represented in two parts: the surface representation used to draw characters (called skin or mesh ) and a set of interconnected bone hierarchies (called framework or rig ) are used to animate ( poses and keyframes ) mesh. While this technique is often used to turn on humans or more commonly for organic modeling, it only serves to make the animation process more intuitive and the same techniques can be used to control the deformation of any object - doors, spoons, buildings, or galaxies. When an animated object is more common than, for example, the humanoid character of the bone set may not be hierarchical or interconnected, but only represents a higher level description of the mesh or skin movements that affect it.
This technique was introduced in 1988 by Nadia Magnenat Thalmann, Richard LaperriÃÆ'¨re, and Daniel Thalmann. This technique is used in almost all animation systems where the simplified user interface allows the animator to control frequently complex algorithms and large numbers of geometries; especially through reverse kinematics and other "goal-oriented" techniques. In principle, however, the intention of this technique never mimics real anatomy or physical processes, but only to control the deformation of mesh data.
Video Skeletal animation
Teknik
Rigging makes our characters move. The rigging process is that we take a digital statue, and we start building skeletons, muscles, and we attach skin to characters, and we also create a set of animated controls, used by our animators to push and pull bodies. around.
This technique is used by building a series of 'bones,' sometimes referred to as rigging . Each bone has a three-dimensional transformation (which includes position, scale and orientation), and an optional parent bone. Therefore bone forms a hierarchy. The full transformation of the child knot is the product of its parent transformation and its own transformation. So moving the femur will move the lower legs as well. When characters are animated, bones change their transformation over time, under the influence of some animation controllers. A rig generally consists of advanced kinematics and reverse kinematics that can interact with each other. Skeletal animation refers to the advanced kinematics section of the rig, where a complete set of bone configurations identifies a unique pose.
Each bone in the frame is associated with some part of the visual representation of characters. Skinning is the process of making this association. In the most common case of polygonal mesh characters, bone is associated with a group of vertices; for example, in the human model, the 'thigh' bone will be associated with a knot that forms a polygon in the model's thighs. The parts of the character's skin can usually be associated with many bones, each having a scaling factor called vertex weights, or combining weights. The movement of the skin near the joints of two bones, therefore can be affected by both bones. In most state-of-the-art graphics machines, the skinning process is done on the GPU thanks to the shader program.
For polygonal mesh, each point can have a mixed weight for each bone. To calculate the final position of the vertex, the transformation matrix is ​​made for each bone which, when applied to the vertex, first places the vertex in the bone space then places it back into the mesh space, the vertex. After applying the matrix to the point, it is scaled to the appropriate weight. This algorithm is called the skinning palette matrix, because the bone transformation set (stored as transforming the matrix) forms a palette for the vertex skin to choose from.
Benefits and disadvantages
Strength
- The bone represents a set of nodes (or some other object, representing eg the foot).
- Animators control fewer model characteristics
- Animators can focus on large-scale movements.
- The bones can independently be moved.
- Animators control fewer model characteristics
Animation can be defined with simple movements of bones, not vertex by vertex (in case of polygonal mesh).
Weakness
- The bone represents a set of nodes (or other objects).
- Does not provide realistic muscle movements and skin movements
- Possible solutions to this problem:
- A special muscle control attached to the bone
- Consultation with a physiologist (improving the accuracy of musculoskeletal realism with a more thorough virtual anatomical simulation)
Maps Skeletal animation
Apps
Skeletal animation is the standard way to animate characters or mechanical objects for long periods of time (usually more than 100 frames). These are typically used by video game artists and in the film industry, and can also be applied to mechanical objects and other objects made of rigid elements and connections.
Capturing performance (or motion capture) can speed up the development time of skeletal animation, as well as increase the level of realism.
For movements that are too dangerous for performance capture, there are computer simulations that automatically calculate motion physics and obstacles with a skeletal framework. The nature of virtual anatomy such as weight of the limb, muscle reaction, bone strength and joint constraints can be added to bounce, bend, fracture and tumbling effect known as virtual action. However, there are other applications of virtual anatomy simulations such as military and emergency response. Virtual troops, rescue workers, patients, passengers, and pedestrians can be used for training, virtual engineering, and virtual equipment testing. Virtual anatomical technology can be combined with artificial intelligence for improved animation technology and further simulation.
See also
- Awful (animated)
- Computer animation
- 3D computer graphics
- Advanced kinematic animation
- Upside kinematics
- Morph target animation
- Interactive simulation based on framework
- Crop animation
References
Source of the article : Wikipedia
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