NPR Lenses



NPR Lenses is an interactive technique for producing '''expressive non-photorealistic renderings'''. It provides an intuitive visual interaction tool for illustrators, allowing them to seamlessly apply a large variety of emphasis techniques. NPR Lenses can apply object-independent adjustments in 3D. Regions of emphasis can be easily created by adjusting lens parameters and any combination of line style, type, shape, and position of computer-generated lines. NPR Lenses support the creation of effects similar to those found in many existing hand-drawn illustrations and allow creative freedom through interactive control at the same time.


Within our NPR Lens framework several different types of effects can be created with the same interaction metaphor. Here are some examples.

Some pictures we created for the papers

Changing Line Thickness

Changing Line Colour

Showing Hidden Lines (aka Magic Lens)

Constraining Effects

Combination of Effects

Some pictures people from the lab created

(we only gave them about 15mins to learn and use the tool)



NPAR Poster


Petra Neumann, Tobias Isenberg, and Sheelagh Carpendale (2007) NPR Lenses: Interactive Tools for Non-Photorealistic Line Drawings. In Andreas Butz, Brian Fisher, Antonio Kr\"{u}ger, Patrick Olivier, and Shigeru Owada, eds., Proceedings of the 7th International Symposium on Smart Graphics (June 25–27, 2007, Kyoto, Japan). Berlin, Heidelberg. Springer-Verlag, pages 10–22, 2007.   doi
Petra Neumann, Tobias Isenberg, Sheelagh Carpendale, and Thomas Strothotte (2005) Expressive Distortion of Strokes and 3D Meshes. Technical report 2005-776-07, Department of Computer Science, University of Calgary, March 2005.   doi
Petra Neumann, Tobias Isenberg, and Sheelagh Carpendale (2006) NPR Lenses: Local Effect Control for Non-Photorealistic Line Drawings. In Doug DeCarlo and Lee Markosian, eds., Posters of the Fourth International Symposium on Non-Photorealistic Animation and Rendering (NPAR 2006, June 5–7, 2006, Annecy, France). 2006. Also see technical report.   pdf

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