Depicting stylized materials with vector shade trees

Abstract

Figure 1: We describe Vector Shade Trees that represent stylized materials as a combination of basic shade nodes composed of vector graphics primitives (a). Combining these nodes allows the depiction of a variety of materials while preserving traditional vector drawing style and practice. We integrate our vector shade trees in a vector drawing tool that allows users to apply stylized shading effects on vector line drawings (b,c). This pdf contains png versions of vector art to avoid viewer compatibility problems; full vector versions of our results are in supplemental material. Original line drawing from koconmus, openclipart.org AbstractVector graphics represent images with compact, editable and scalable primitives. Skillful vector artists employ these primitives to produce vivid depictions of material appearance and lighting. However, such stylized imagery often requires building complex multilayered combinations of colored fills and gradient meshes. We facilitate this task by introducing vector shade trees that bring to vector graphics the flexibility of modular shading representations as known in the 3D rendering community. In contrast to traditional shade trees that combine pixel and vertex shaders, our shade nodes encapsulate the creation and blending of vector primitives that vector artists routinely use. We propose a set of basic shade nodes that we design to respect the traditional guidelines on material depiction described in drawing books and tutorials. We integrate our representation as an Adobe Illustrator plug-in that allows even inexperienced users to take a line drawing, apply a few clicks and obtain a fully colored illustration. More experienced artists can easily refine the illustration, adding more details and visual features, while using all the vector drawing tools they are already familiar with. We demonstrate the power of our representation by quickly generating illustrations of complex objects and materials.

Vectorising Bitmaps into Semi‐Transparent Gradient Layers

“…Another extension of our work would consist in casting the decompositing problem as a global optimisation across multiple layers to better capture residual colour variations, potentially using our greedy solution as an initial solution. Finally, our layered representation could facilitate the creation of vector shade trees [LMPB*13] from existing drawings and photographs, which would represent a first step towards the capture and transfer of material appearance in illustrations.…”

“…The key observation that guides our approach is that complex images often can be explained with just a few simple layers. In fact, researchers have shown that the human visual system infers transparent layers if they result in a simpler explanation of the visual stimuli [Ade93,LZW02]. Vector graphics represent transparency using alpha compositing [PD84], which composites the foreground colour F over the background B using the foreground's opacity channel α:…”

A probabilistic framework for component‐based vector graphics

“…Although some high‐level functionality are supported in these systems, such as image vectorisation tools, the suite of tools available are primarily low‐level tools for creating, manipulating, and organising vector primitives. While low‐level vector representations are still an active area of research [DRvdP14, SVG16], there is also an incentive for high‐level vector tools [LZC11, LMPB*13, GBLM16]. However, to our knowledge, high‐level manipulation and synthesis for layered or component‐based vector graphics have not been previously proposed.…”

Foundry

“…Our underlying representation is inspired by Cook's Shade Trees [5]. A similar approach has been employed for 2D illustrations [20]. The system architecture and programming model have similarities to RenderMan [6] and shading languages [15].…”