Defining New Strokes

The user simply drags out a stroke definition box in the middle of which is an L-shaped line (Figure 8). The horizontal part and the vertical part of the L-shaped line represents the stroke's reference backbone and the reference thickness respectively. The L-shaped line provides a scale for the new stroke, and everything within the box would be included as part of the stroke. If the orientation of the new design is not aligned with the reference backbone, the user...

Comics and Animation

One interesting application of skeletal strokes that we have been exploring is its use in comics and stylish animation production. Snoopy and the characters in 'The Yellow Submarine' are characters falling under this category 18 . Comics is a now a highly respected sub-culture in many countries especially in Japan. Works by famous comics artists like Tezuka Osamu 37 have even been studied and given literary praise. Pragmatically, comics publishing is also a mega-dollar business. Even though...

Review on Skeletal Stroke Deformation

The skeletal stroke deformation has been discussed in detail in 28 , here we will only briefly go through the main points but leave out the mathematical details and derivations. The skeletal stroke deformation is based on localized parametric coordinate system transformation along the stroke application path. A skeletal stroke is defined by specifying a reference backbone and a reference thickness on any arbitrary picture. The purpose of defining the reference backbone and thickness is for...

Strokes Skeletons And Envelopes

The constant thickness stroke is still the basic drawing primitive provided by most commercially available vector based drawing packages 34,39 . To create pictures like figures 2, 3, 17 and 19 with these packages usually involves scanning in an original copy (which has already been created on paper) or tracing out its outlines manually or automatically. Indeed, many impressive illustrations that fill the pages of manuals of many market-leading packages are there to demonstrate the package's...

Speed Lines for Motion Blurring

In both comics and animation, fast action is often represented by speed lines, which suggest the distance an object or character has travelled across the camera before its shutter is closed again. Motion blurring is particularly important in animation because it reduces temporal aliasing effects. Its method of generation in vector based cartoon has not been, however, a well addressed problem. One possible way is to employ temporal antialiasing techniques like stochastic sampling across the time...

Rendering a Recursive Stroke

Rendering a recursive stroke explicitly by determining the resultant geometry is in general impossible. Since a recursive stroke is equivalent to an IFS (Iterated Function System) code (with a condensation set if objects other than itself are present in the definition) 3,4,5,6 , the attractor is often a fractal with a fractal dimension less than 2. We therefore have to resort to one of the approximation methods for rendering these fractals. The Escape Time Algorithm 4 would result in a clean...

Controlling a PseudoD Stroke

We have demonstrated how to create an illusion of rotation by making use of the general anchoring mechanism. To perform that deformation, only one control parameter, the aspect ratio of the stroke, has been used. We could in theory control any kind of deformation of a picture with the aspect ratio alone. If different features in a picture are to change in different ways, however, it would be more convenient to have independent controls. easily set up an external control system by which users...

General Drawing Applications

We anticipate that skeletal strokes would have considerable impact on many drawing applications in fashion design where stylish bold strokes are often used in interior design where pseudo-3D strokes representing furniture and architectural objects can be laid out with ease in dynamic clip-arts which can deform dramatically beyond the limits of stretching, shrinking, shearing, twisting and bending. If implemented in windowing system kernels or page description languages like PostScript, the...

Animation with Skeletal Draw

Animation takes full advantage of the picture and deformation abstraction capability provided by skeletal strokes. The Skeletal Draw program has also been built with facilities to generate animation sequences. Traditional key-frame technique is used by Skeletal Draw. To create the key-frames, the user directly manipulates the characters in the scene. The system then calculates the in-betweens by interpolating Catmull-Rom splines. After the keyframes have been laid out, the program can do a...