Non-Photorealistic Computer Graphics Library

A 2.5D Modelling and Animation Framework Supporting Computer Assisted Traditional Animation

Author(s): Fabian Di Fiore.
PhD Thesis: School of Information Technology, Transnational University of Limburg, June, 2004.
[BibTeX]

Abstract:
Traditionally, 2D animation production has been a labour-intensive artisan process of building up sequences of drawn images by hand which, when shown one after the other at a fixed rate, resemble a movement. Most work and hence time is spent on drawing, inking and colouring the individual animated characters for each of the frames. Existing computer assisted animation already has a huge impact on traditional animation. However, the most time-consuming and labour-intensive aspect — in-betweening — is not well enough computerised that it could be (completely) performed by the computer and thus replacing traditional animation. Moreover, there is also a legitimate concern that the extensive computerisation will remove much of the creative aspects of the process. This dissertation introduces a new method for automatic in-betweening in computer assisted traditional animation. The solution is based on novel 2.5D modelling and animation techniques within the context of a multi-level approach, starting with basic 2D drawing primitives at level 0, over explicit 2.5D modelling structures at level 1 and inclusion of 3D information at level 2, to high-level tools at level 3. Similar to the 3D animation process, our method also distinguishes clearly between a modelling and an animation phase. Next to automatically calculating in-between frames, we particularly focus on reintroducing necessary 3D information — which is only present in the animator’s mind — in order to preserve volumes and proportions, and to prevent temporal aliasing. We also present new techniques and tools to draw, manipulate and animate (stylised brush) strokes, in order to preserve the natural way of drawing and editing, and to give the animator the same freedom of exaggeration to create animations as s/he is bearing in mind. Furthermore, we describe a novel approach to design artistic and believable trees in a cartoon-like style, and an extension of this approach to the more turbulent movements of a series of gaseous phenomena. We believe that the provided solutions are easy to use, and empower a much quicker cartoon production without hampering the artists’ creativity.