Inter-color NPR lines: A comparison of rendering techniques

Donald G Herring, Purdue University

Abstract

Renders of 3D scenes can feature lines drawn automatically along sharp edges between colored areas on object textures, in order to imitate certain conventional styles of hand-drawn line art. However, such "inter-color lines" have been studied very little. Two algorithms for rendering these lines were compared in this study - a faster one utilizing lines baked into the textures themselves and a more complex one that dynamically generated the lines in image space on each frame - for the purpose of determining which of the two better imitated traditional, hand-drawn art styles and which was more visually appealing. Test subjects compared results of the two algorithms side by side in a real-time rendering program, which let them view a 3D scene both passively and interactively from a moving camera, and they noted the differences between each technique's relative line thicknesses - the key visual disparity - in order to reach final judgments as to which better adhered to artistic conventions and which was more appealing. Statistical analysis of the sample proportions that preferred each algorithm failed to prove that any significant difference existed between the two algorithms in terms of either of the above metrics. Thus the algorithm using baked lines appeared to be more recommendable overall, as it was known to be computationally faster, whereas the dynamic algorithm was not shown to be preferred by viewers in terms of conventionality or aesthetics.

Degree

M.S.

Advisors

McGraw, Purdue University.

Subject Area

Aesthetics|Computer science

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