The Visual Computer (2018) 34:817–827
An image-based method for animated stroke rendering
· László Szirmay-Kalos
· László Szécsi
· Zoltán Lengyel
· Gábor Marinov
Published online: 8 May 2018
© Springer-Verlag GmbH Germany, part of Springer Nature 2018
This paper presents an image-space stroke rendering algorithm that provides temporally coherent placement of lines at particles
that are moving with object surfaces. We generate particles in image space and move them according to an image-space velocity
ﬁeld. Consistent image-space density is achieved by a deterministic rejection-based algorithm that uses low-discrepancy series
to ﬁlter out overpopulated areas and to ﬁll in underpopulated regions. Our line stabilization method can solve the temporal
continuity problems of image-space techniques. The multi-pass algorithm is implemented entirely on the GPU using geometry
shaders and vertex transform feedback. Our method provides high-quality results and is implemented as an interactive post
processing step. We also provide a wide toolset for artists to control the ﬁnal rendering style and extended the method to
process real-life RGBZ footage.
Keywords NPR · Stroke rendering · Hatching
An important challenge of the application of non-photo-
realistic rendering (NPR) to animation is temporal coherence.
It is hard to ensure that stylized lines, illustrative surface
details or lighting features properly, follow the motion of
the objects and the camera, and without sudden changes or
ﬂickering. Fixing these features in image-space produces an
annoying artifact called the shower door effect, which makes
the static pattern observable, akin to looking through a tex-
tured glass door.
We focus on stroke-based techniques like pen and ink
illustration or pencil drawing, where the lighting, shadows
and the shape of the objects are represented with the den-
sity and orientation of typically high number of thin hatch
lines. To mimic the traditional 2D manual drawing, hatching
density, line length and width must be consistent in screen
space. Hatch lines should be placed more densely in shad-
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s00371-018-1531-9) contains supplementary
material, which is available to authorized users.
Department of Control Engineering and Information
Technology, Budapest University of Technology and
Economics, Budapest, Hungary
Limes Superior Ltd., Budapest, Hungary
owed areas, and their orientation and bending should well
describe the underlying geometry.
The main contributions of this paper are as follows:
– A deterministic stroke animation method using rejection
sampling and low-discrepancy series that guarantee the
right density of particles and their associated image-space
strokes even when 3D objects move or deform.
– A collection of techniques and anti-ﬂickering algorithms
that maintain temporal continuity even when strokes
follow unstable principal curvatures and normal vector
estimates are inaccurate.
– The deﬁnition of a versatile set of artistic controls.
– A real-time rendering system running on the GPU, which
is appropriate for integration into production rendering
systems working with both computer generated and cap-
tured RGBZ images.
2 Previous work
Bénard et al. give a detailed survey of stylized rendering in 
and categorize related work as texture-based and primitive-
In texture-based methods, the artistic style is given by
a texture, which is mapped either onto the surface of 3D
objects [21,22] or directly onto the screen . Mapping
onto the objects ensures perfect motion coherence, but it is
hard to control the image-space line density due to perspec-