My goal is to give my artwork the weathered look of medieval paintings.
To accomplish this, I create custom shaders and compositing networks using
Side Effects' Houdini software.
The shaders cover the painting with craquelure (a pattern of tiny cracks),
stains and grime. I also wrote a brush-stroke shader which takes into account the shapes
of objects in the painting. This makes it possible to procedurally
recreate the look of brush strokes applied by a human painter.
I use various CG techniques to create backgrounds, crowds, and high-detail areas—
just as old masters employed apprentices to handle the more mundane aspects of their paintings.
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Cavalry created with a crowd system
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Distressed wood (digital)
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Simulated craquelure
(based on an L-system)
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Riders processed with a paint shader. |
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Researching craquelure led to interesting findings.
As it turns out, not all cracks are created equal.
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Mud cracks are typically non-hierarchical. Drying mud breaks up
uniformly into regions of similar size, which have 6 sides on average.
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Craquelure is usually hierarchical.
Cracks accumulate over time, forming progressively finer lines. The
subdivisions tend to be rectangular rather than hexagonal.
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In a hierarchical pattern, cracks form localized regions, which resemble city
blocks on a map. Note how width varies among hierarchies. |
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Hierarchical cracks on glazed ceramics
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Hierarchical pattern generated with a computer simulation. Stained glass window, perhaps?
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Hierarchical cracking in action.
Who said watching paint dry is boring?
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