CREATIVE COMPUTING II: INTERACTIVE MULTIMEDIA COURSEWORK ASSIGNMENTS 2016 -2017 DIGITAL ANIMATION TWEENING OR INBETWEENING Tweening or Inbetweening is a defined as a procedure a defining a smooth transitional and perfect motion of the first object into the second object by creating intermediate frames (Meraj et al, 2017). It is one of the most famous animation techniques used in the animation industries for past few years. The frames used in between the two objects are called as key frames or tween frames. It helps to improve the motion animation. This type of animation is applied in both digital animation and traditional animation such as hand drawn animation. The tweening is defined as a process of calculating the movement of one or more point from its starting position to an ending position. The linear interpolation is used for calculating the tweening in a straight line. The formula used for calculating the tweening positions is P=A(1-t)+Bt Whereas A is an initial position of one or more points B is a final position of one or more point t is a time variation from 0 to 1 In traditional animation, the lengthy long cycle of keyframes is one of the main disadvantages (N. Kamat et al, 2014). Usually, it will take more time to create a single frame for this type of animation. In past, few years, to overcome these disadvantages, the inbetweening is used for achieving the best result. MOTION TWEENS Motion tweens are defined as a creating movement in animation characters (Ebenstein et al, 2016). The different values such as position, size, color, effects, filters and rotation are some of the important metrics used for creating animation movements between the first frame and last frame in motion tweens. Any frames between the two objects are selected for making the movement of animation character. The motion symbol is moved between the selected frames. In motion tween, an automatic motion path is created between the frames. The classic and shape tweens do not have an automatic motion path facilities like motion tweens. CLASSIC TWEEN classic tween is defined as the first type of tweening which is used for transition purpose. This method has several disadvantages. The classic tween is a process of creating a long lengthy cycle frame which takes time, cost and more manual resource. It is more complicated and not flexible process compared to motion tweens and shapes tweens (Ragan et al, 2016). All the changes in the classic tween frame are edited and added in the keyframe. These keyframes are mainly used for defining a motion of animated character. The empty keyframe is used for defining the space or resume the motion of animated character. SHAPE TWEEN A Shape tween is defined as a process of morphing from one shape to another shape in specific time. In this tween, creating a shape in one frame, creating another shape in another frame and interpolating these two frames by creating a morphing keyframe. There are two types of stroke used in this type of tween. They are non-uniform fancy strokes and uniform solid strokes. The Variable Width Tool is used for increasing the metrics of strokes used for animation object. The animation points generated between the two keyframes is used for giving a hint about the beginning shape (Root and Mostak, 2016). To control more complex or improbable shape changes, you can use shape hints. Shape hints identify points that should correspond in starting and ending shapes. Shape hints contain letters (a through z) for identifying which points correspond in the starting and ending shapes. There are 26 shape hints in animation shape tweens. Shape hints are yellow in a starting keyframe, green in an ending keyframe, and red when not on a curve. TRADITIONAL ANIMATION A traditional animation technique is a process of creating an animation using handwritten images. This type of animation had been used in the cinema until the invention of computer animation. The cel animation and stop motion animation are two types of traditional animation methods used in the past. They mainly used hand drawing, hand inking and hand painting are some the process used for creating these two animations. The process of this type of animation has several steps. The first step is deciding the story. The second step is converting the story into the animation film script. The best example for the traditional animation stories is comic books which were published before the advent of computer graphics. The scripted images in the comic books are hand drawn diagrams. The storyboard consists of camera shots and consecutive sketches (Heer et al, 2007). Every time the diagrams are redrawn or rewritten based on the story. The third step in the traditional animation process is voice recording. The sound is recorded first before the creation of animation. Because it is easy to combine the pre-recorded sound and animation than the pre-created animation and sound. The fourth step in the traditional animation process is animatic or frequently called as story reel. This story reel fully consists of soundtrack and pictures. This story reel is mainly used for editing the pictures to solve the time related issues (Baki et al, 2015). Every time the story board review the animatic to create a perfect animation without any flaws. The final step is animation. It is created after the animatic or story reel is approved. The artist began to draw papers diagrams of all characters based on the storyboard. The transparent papers are used for creating consecutive diagrams in the storyboard (Sunil and Stefan, 2017). A peg bar animation tool is used for creating a final animation. The pin in the peg bar is fitted with the transparent paper and key animator will create an animation diagrams based on the transparent paperwork. The key animator will draw a character based on the guide. The key animator will able to draw frames to create the action of animated character and the character can jump across a gap, two or more frames are added in the character, when it is flying and the frame for the character landing on the other side of the gap. DISCUSSION Issues in the traditional animation The main disadvantage of the traditional animation is time-consuming. the key animators must draw characters for every frame. It takes more time and many animators are also needed to finish one movie (Lino et al, 2011). The correcting mistakes in traditional animation are very tough when compared to computer animation. Because the process should repeat everything from start in traditional animation when the error occurs. Issues in digital animation The main disadvantage of this process is lengthy cycles, number of steps for creating single frame are more when compared to other tweens. Because of the more number of steps, it leads to confusion at the end of the process. Since it has a higher number of steps we cannot identify the bugs in that process. It is a time-consuming process and a lot of manual resources is needed. D) Catmull–Rom spline Animation The creating a code for tweening process is easy when compared to the traditional animation process. The loop is created based on the interpolation algorithms such as Catmull-Rom curves which are used for calculating the position of every point. This mathematical tool is used for analyzing and calculating the position. This method also has a variable called time variation which is used for the calculation of tweening process. The generating the key frames for tweening objects are one of the important processes in animation (Beda et al,2010). These two generated frames should have equal points and have a perfect fluid motion from one point to another point. A meaningful mapping is one of the algorithms used for generating the process of time frames between the objects. Catmull-Rom curves are one of the important technique and widely used method in animation for a variety of applications ranging from modeling to graphics. Catmull–Rom spline is a variant form of animation method and it is an interpolating spline which is defined by four points with P0, P1, P2 and P3. The human figure animation is created by generating a set of point or position and orientation. The Cartesian coordinates are used for creating a motion of human figure animation. The in between is called key frames are used for smooth prediction and evolution of cartoon characters. It is calculated by the interpolating a set of points to generate a fluid motion. This method has three important properties because of this property they have been used widely in the animation industry. The First property is, the curves are smooth and interpolate their control points, which gives the user direct control over various points on the curve. The second property is the control point helps to support the curves which affect a small neighborhood on the curve. Finally, the third property of Catmull-Rom is an explicit piecewise polynomial representation which is used for converting the other bases and manipulated computationally. Catmull–Rom spline has several features compared to the other algorithms used in animation for calculating the positions. It is explained in (Dyn et al, 2009) Catmull-Rom curve does not form loop or self-intersection within a curve segment. Since it does not form any loop, it has very good control over a neighborhood points. These feature helps to improve the movement of the objects easily. In computer animation, Catmull-Rom spline has also been used to calculate an active model for segmentation. The method is termed active spline model which is explained in (Lino et al, 2010). The model is devised based on active shape model but uses Catmull-Rom spline to join two successive points (active shape model uses simple straight line), so that the total number of points necessary to depict a shape is less.