Today it is the time that we have come to the end of the fascinating article series about animation technology. In our last article we talked about Mesh-on-Skeleton Animation, and so today it is time for the part no. 3 out of 3 which is regarding Motion Capture Technology. This article finishes the "Trilogy" called The Study of Animation, but be sure that we will come back with some more interesting articles in the nearest future. Moreover, we hope some of you got some ideas now how animation movies such Avatar, Ice of Age or others has been made and how our favourite animating characters were brought into life!

Animation techniques applied to a virtual character have a large number of applications being done so far. However, the animation technology is a pretty young subject and there is still a need for the application that combines different techniques to present full-functional animation system.

The study introduces specific research areas:

-    Hierarchical Modelling for Animation (Part 1)
-    Mesh-on-Skeleton Animation (Part 2)
-    Motion Capture Technology (Part 3)

Motion Capture Technology

Motion Capture technology relates to several techniques such like Rotoscoping, channel animation or full motion capture. Animator O’Rourke says they are used in situations where animation needs to be extremely accurate in terms of producing the motion of human or animal to meet the real world behaviours of given objects.

The debate about using a set of different mocap approaches brings to life common issues about receiving the digital data from specialized equipment and modifying this data to get best results. The algorithms developed by some Computer Graphics scientists are based on an articulated body model, dynamical modelling and stochastic search. According to this, a body mesh is placed around the framework of a kinematic tree then specialized tool, called edge detection mask, finds the edges and fits a mesh smoothly. Hence, the mesh is being processed by thresholded background subtraction to produce the pixel map, thereafter to obtain and visual body motion. Another scientists show the way of developing a human motion capture from a single camera system without using any markers placed on a model. Scientist J. Saboune presents new and unique algorithm, called Interval Particle Filtering, used in tracking human movements, where the input images from the camera are subjected to a set of filters to obtain 3D digital model representation.

Both of these techniques are an alternative to standard magnetic or optical systems which are supported in commercial software packages, for example Autodesk Motion Builder, to get and process the data. In spite of it is an expensive technology; mocap has become very powerful as it delivers a large number of strong points by its effectiveness and flexibility, by recording complex movements and producing realistic animations.  

However, another way of capturing the motion is Channel Animation. Channel Animation allows producing animation in real-time applications by manipulating an input device (mouse or keyboard). This method requires a linkage between the x, y, z values in 3D coordinate system of an avatar and the input device to rotate or translate the object. In practice, movement of a mouse causes the movement of avatar.

The data calculation process using Mocap:

Here is the example of Mocap System pipeline:
•    Calibration
•    Capture
•    3D Position Reconstruction
•    Fitting to the Skeleton
•    Post Processing (motion editing, motion warping)

We hope all of you have enjoyed the The Study of Animation "Trilogy" and learnt something while reading about the theory of animation technology. Computer Generated Imager (CGI) is a very fascinating application and Hypernova Design has been into animation for years using many 3D software programs such 3DS MAX, Maya or Blender. Do not forget animation technology involves many other amazing subjects such 3D modelling, lighting or texturing, but we will talk about these in the future. Cheers!

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