NijiGPen: Blender Grease Pencil Add-on

[ 📖 Documentation ] | [ 🎥 YouTube Demos ]

NijiGPen is a Blender add-on that brings new features to Grease Pencil for creating 2D graphic design and illustrations. It provides with the following functions:

• 2D algorithms for vector shapes and strokes (e.g., Boolean and Offset)
• Refinement and cleanup of hand-drawn 2D strokes
• Conversion from 2D shapes to 3D meshes
• Data exchange with other painting/designing tools

Please note that the development of this add-on is still in an early stage. Bugs may exist and UI/operators may change frequently.

Installation

Requirement: Blender 3.3 or later

Please follow the steps in this page to finish the installation.

This add-on requires third-party Python packages. Please check these details if you have any questions during installation.

Features

Credits

The functions of this add-on are implemented with the following packages:

• Pyclipper wrapper by Maxime Chalton and the Clipper library by Angus Johnson
• Triangle by Dzhelil Rufat and Jonathan Richard Shewchuk
• SciPy
• Scikit-image

Besides, although not using the codes directly or implementing the same algorithm, the functions of this add-on are largely inspired by the following works:

• Lee, In-Kwon. "Curve reconstruction from unorganized points." Computer aided geometric design 17, no. 2 (2000): 161-177.
• Liu, Chenxi, Enrique Rosales, and Alla Sheffer. "Strokeaggregator: Consolidating raw sketches into artist-intended curve drawings." ACM Transactions on Graphics (TOG) 37, no. 4 (2018): 1-15.
• Dvorožňák, Marek, Daniel Sýkora, Cassidy Curtis, Brian Curless, Olga Sorkine-Hornung, and David Salesin. "Monster mash: a single-view approach to casual 3D modeling and animation." ACM Transactions on Graphics (TOG) 39, no. 6 (2020): 1-12.
• Johnston, Scott F. "Lumo: illumination for cel animation." In Proceedings of the 2nd international symposium on Non-photorealistic animation and rendering, pp. 45-ff. 2002.
• Hudon, Matis, Sebastian Lutz, Rafael Pagés, and Aljosa Smolic. "Augmenting hand-drawn art with global illumination effects through surface inflation." In Proceedings of the 16th ACM SIGGRAPH European Conference on Visual Media Production, pp. 1-9. 2019.
• Sýkora, Daniel, John Dingliana, and Steven Collins. "Lazybrush: Flexible painting tool for hand‐drawn cartoons." In Computer Graphics Forum, vol. 28, no. 2, pp. 599-608. Oxford, UK: Blackwell Publishing Ltd, 2009.
• Parakkat, Amal Dev, Pooran Memari, and Marie‐Paule Cani. "Delaunay Painting: Perceptual Image Colouring from Raster Contours with Gaps." In Computer Graphics Forum, vol. 41, no. 6, pp. 166-181. 2022.