Paint-on-Glass Animation: The Fellowship of Digital Paint and Artisanal Control Tom van Laerhoven, Fabian Di Fiore, William van Haevre, Frank van Reeth To cite this version: Tom van Laerhoven, Fabian Di Fiore, William van Haevre, Frank van Reeth. Paint-on-Glass Ani- mation: The Fellowship of Digital Paint and Artisanal Control. Computer Animation and Virtual Worlds, Wiley, 2011, 22 (2-3), pp.325. 10.1002/cav.406. hal-00629936 HAL Id: hal-00629936 https://hal.archives-ouvertes.fr/hal-00629936 Submitted on 7 Oct 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. 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Computer Animation and Virtual Worlds Paint-on-Glass Animation: The Fellowship of Digital Paint and Artisanal Control Journal: Computer Animation and Virtual Worlds Manuscript ID: CAVW-11-0018 Wiley - Manuscript type: Special Issue Paper Date Submitted by the 04-Mar-2011 Author: Complete List of Authors: Van Laerhoven, Tom; Hasselt University, Expertise Centre for Digital Media Di Fiore, Fabian; Hasselt University, Expertise Centre for Digital Media Van Haevre, William; Hasselt University, Expertise Centre for Digital Media Van Reeth, Frank; Hasselt University, Expertise Centre for Digital Media animation, 2D animation, painterly animation, paint system, paint- Keywords: on-glass Note: The following files were submitted by the author for peer review, but cannot be converted to PDF. You must view these files (e.g. movies) online. CASA2011_#77_figures.zip http://mc.manuscriptcentral.com/cavw - For Peer Review Page 1 of 25 Computer Animation and Virtual Worlds 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Paint-on-Glass Animation 15 16 17 18 The Fellowship of Digital Paint and Artisanal 19 20 21 22 23 Control 24 25 26 27 Tom Van Laerhoven Fabian Di Fiore William Van Haevre 28 29 30 Frank Van Reeth 31 32 33 Hasselt University – tUL – IBBT 34 35 36 Expertise Centre for Digital Media 37 38 39 40 Wetenschapspark, 2 41 42 43 BE-3590 Diepenbeek, Belgium 44 45 46 ftom.vanlaerhoven, fabian.difiore, william.vanhaevre, [email protected] 47 48 49 http://www.edm.uhasselt.be 50 51 52 53 Abstract 54 55 56 In this paper we deal with paint-on-glass animation, which is a technique for mak- 57 58 59 60 1 http://mc.manuscriptcentral.com/cavw - For Peer Review Computer Animation and Virtual Worlds Page 2 of 25 1 2 3 4 5 6 7 8 ing animated films by pushing slow-drying paints from frame to frame directly under 9 10 the camera. As artwork is continuously destroyed upon creating new frames, the ani- 11 12 mator is not able to rehearse or refine the animation afterwards. Furthermore, due to 13 14 impracticable issues like how to stack up layers containing wet paint or how to overlay 15 16 17 masks on the wet medium, one has to take both creative as technical decisions for each 18 19 shot. 20 21 Our approach consists of an interactive paint setup that physically simulates paint 22 23 24 media. Together with a set of digital tools the artist is relieved from the difficult task 25 26 of sustaining a constant frame-to-frame coherence while animating and is given the 27 28 possibility to modify or undo earlier paint modifications. Regarding the interaction part, 29 30 31 the artist stays in full control by employing a tangible interface. This allows artists to 32 33 push pigment with their fingers, use special-purpose digital brushes, or even to employ 34 35 real life tools like paper tissue. 36 37 38 Feedback from artists confirms the real-life behaviour of stretching and smudging 39 40 the paint as well as interacting with the setup, resulting in a natural and reality-based 41 42 methodology. 43 44 45 46 Keywords: animation, 2D animation, painterly animation, paint system, paint-on-glass 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 http://mc.manuscriptcentral.com/cavw - For Peer Review Page 3 of 25 Computer Animation and Virtual Worlds 1 2 3 4 5 6 7 8 Introduction 9 10 11 In spite of its name, paint-on-glass animation is best defined as a technique for making an- 12 13 14 imated films by pushing around some kind of (wet) medium directly under the camera and 15 16 recording it frame-by-frame (Figure 1). It is categorised as an “under-the-camera-technique” 17 18 as it is nearly always undertaken by an individual artist or animator rather than by a produc- 19 20 21 tion studio using factory-like processes. As the medium is pushed around directly under the 22 23 camera and recorded frame-by-frame, each image seems to merge from the previous one and 24 25 26 melt into the next, resulting in movement that can be very fluid and organic – a continual 27 28 process of metamorphosis. 29 30 31 A well-known practitioner of the paint-on-glass animation technique is Russian animator 32 33 Aleksander Petrov. His most famous work is the award winning short film “The Old Man 34 35 36 and the Sea” which took two and a half years to complete [1] illustrating the complexity of 37 38 the technique. 39 40 41 42 Motivation. As the medium is pushed around from frame to frame, artwork is contin- 43 44 45 uously destroyed as new artwork is created. Without the ability to rehearse and refine the 46 47 animation and without the disposal of layering and masking tools, the animator must plough 48 49 50 on regardless incorporating any errors into the sequence. 51 52 On the one hand this stimulates spontaneity and delivers work that is very fresh and 53 54 55 distinctive as it celebrates the method of its making. For example, characters may move from 56 57 place to place not by walking, but by being smudged away to re-form out of the background 58 59 60 3 http://mc.manuscriptcentral.com/cavw - For Peer Review Computer Animation and Virtual Worlds Page 4 of 25 1 2 3 4 5 6 7 8 at the required location. On the other hand, this particular form of step-ahead animation 9 10 is a painstaking process which demands much self-discipline, endurance and concentration 11 12 as the resulting frames are never a series of clean images of the kind produced by other 13 14 15 animation techniques, but also contain a record of their making due to the pushing process. 16 17 18 19 Contribution. In this paper we present our approach to facilitate paint-on-glass anima- 20 21 tion. In close collaboration with artists and animators we developed a set of digital tools 22 23 24 that do enable them to achieve the fine quality of a finished painting for each frame, while 25 26 preserving all artisan control. 27 28 29 Primarily, our system features: 30 31 32 ² a real-time free-form paint tool to physically simulate the complex behaviour of dif- 33 34 35 ferent paint media (gouache, watercolour, impasto, pastel); 36 37 38 ² painting/animating by pushing the drawing media around resulting in a stretch and 39 40 smear effect; 41 42 43 44 ² a tangible interface consisting of a multitouch screen allowing the use of one’s fingers 45 46 as well as physical media including brushes and tissues; 47 48 49 50 ² several tools that are absent in the traditional method due to the wet nature of the 51 52 painting media such as working with layers and masks; 53 54 55 ² the availability of animation tools like onion skinning and flipbook animation; 56 57 58 59 60 4 http://mc.manuscriptcentral.com/cavw - For Peer Review Page 5 of 25 Computer Animation and Virtual Worlds 1 2 3 4 5 6 7 8 ² digital tools to control the drying time, correct mistakes, remove pigment and/or water 9 10 as desired, and the ability to save, load or reuse (intermediate) results. 11 12 13 14 Paper Organisation. First, we survey work we consider related to ours. Next, we describe 15 16 our approach starting from the employed painting setup to an overview of the digital paint- 17 18 19 on-glass animation process. Finally, clarifying examples are provided in which we also 20 21 discuss our results. 22 23 24 25 26 27 Related Work 28 29 30 We start this section by giving a brief overview of traditional paint-on-glass animation. 31 32 33 Then, we elaborate on digital paint solutions that we consider related to ours. 34 35 36 37 Traditional Paint-on-Glass Animation 38 39 40 41 What we give here is an account as it might be for a practiced artist in a home studio. 42 43 We separately discuss the painting process (i.e. painting a single frame) and the animation 44 45 process (i.e. making a series of drawings). 46 47 48 49 Painting. The painting process itself resembles painting on a canvas as the initial paint is 50 51 52 added with brushes or other tools including sponges, cotton buds, small sticks, strong tissue 53 54 or even fingers.