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Rendering Plant Leaves Faithfully
Rendering Plant Leaves Faithfully
Oliver Franzke (Dresden University of Technology)
Oliver Deussen (University of Konstanz)
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ContentsContents
1.1. Optical properties of plantsOptical properties of plants
2.2. Previous approachesPrevious approaches
3.3. The new methodThe new method
4.4. ResultsResults
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Optical properties of Optical properties of plantsplantsOptical properties of Optical properties of plantsplants
• have been studied for years
• are interesting for:
– computer graphics
– biologists
– architects
– …
• are very important, because we see plants every day…
• have been studied for years
• are interesting for:
– computer graphics
– biologists
– architects
– …
• are very important, because we see plants every day…
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Optical properties of Optical properties of plantsplantsOptical properties of Optical properties of plantsplants
• a leaf consists of several layers
• each layer causes reflection, refraction and scattering of light
• a leaf consists of several layers
• each layer causes reflection, refraction and scattering of light
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Optical properties of Optical properties of plantsplantsOptical properties of Optical properties of plantsplants
• a BRDF of a real leaf looks like this:• a BRDF of a real leaf looks like this:
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Previous approachesPrevious approaches
• early methods use:– a stochastic model (Tucker and Garatt)– a volumetric model (Govaerts et al.)– a layered model (Baranoski and Rokne)
• each approach tries to be physically correct
– the main problem is the efficiency
– it is difficult to compute complex scenes or animations
• early methods use:– a stochastic model (Tucker and Garatt)– a volumetric model (Govaerts et al.)– a layered model (Baranoski and Rokne)
• each approach tries to be physically correct
– the main problem is the efficiency
– it is difficult to compute complex scenes or animations
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Previous approachesPrevious approaches
• Jensen et al. presented a model to render translucent materials quite fast
• Even highly scattering media can be represented efficiently
• problems:
– difficult to describe heterogeneous materials
– veins of leaves: substructure information is very important
• Jensen et al. presented a model to render translucent materials quite fast
• Even highly scattering media can be represented efficiently
• problems:
– difficult to describe heterogeneous materials
– veins of leaves: substructure information is very important
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The new methodThe new methodThe new methodThe new method
Our goal:
render translucency in plants accurately and efficiently i.e.– calculate animations and/or complex scenes
– light source behind the leaf: one should see veins and other sub-structures
– should be easy to render different types of plants
Our goal:
render translucency in plants accurately and efficiently i.e.– calculate animations and/or complex scenes
– light source behind the leaf: one should see veins and other sub-structures
– should be easy to render different types of plants
![Page 9: Rendering Plant Leaves Faithfully Oliver Franzke (Dresden University of Technology) Oliver Deussen (University of Konstanz)](https://reader035.vdocuments.us/reader035/viewer/2022062720/56649f145503460f94c291ac/html5/thumbnails/9.jpg)
The new methodThe new methodThe new methodThe new method
• real leaves are source for all required information
• a set of seven texture maps is necessary to describe the leaf
• images can be obtained with an ordinary camera and a scanner
• real leaves are source for all required information
• a set of seven texture maps is necessary to describe the leaf
• images can be obtained with an ordinary camera and a scanner
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The new methodThe new methodThe new methodThe new method
• adaxial and abaxial textures• adaxial and abaxial textures
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The new methodThe new methodThe new methodThe new method
• through-light, thickness and extinction• through-light, thickness and extinction
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The new methodThe new methodThe new methodThe new method
• bump and alpha map• bump and alpha map
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The new methodThe new methodThe new methodThe new method
Putting it all together:
• we trace the current view ray as it passes through the leaf
• there are three layers
– The size of each layer is a fixed percentage of the current thickness (Thickness map)
• the view ray is refracted at each boundary
• at each step, we have to sample all lights
Putting it all together:
• we trace the current view ray as it passes through the leaf
• there are three layers
– The size of each layer is a fixed percentage of the current thickness (Thickness map)
• the view ray is refracted at each boundary
• at each step, we have to sample all lights
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The new methodThe new methodThe new methodThe new method
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The new methodThe new methodThe new methodThe new method
• if the light source is at the same side as the viewer, then we use the adaxial (or abaxial) texture map
• otherwise we choose the through-light map (the selected texture map stores the reflected color…)
• the intensity of the light decreases exponentially through passing the leaf interior
• if the light source is at the same side as the viewer, then we use the adaxial (or abaxial) texture map
• otherwise we choose the through-light map (the selected texture map stores the reflected color…)
• the intensity of the light decreases exponentially through passing the leaf interior
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The new methodThe new methodThe new methodThe new method
Optimization/Simplification:
• sample the shadow just once
• approximate the multi-scattered light with an small ambient term
Optimization/Simplification:
• sample the shadow just once
• approximate the multi-scattered light with an small ambient term
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ResultsResultsResultsResults
• the new model is a fast approach… though it is not physically correct
• rendering time between
– some seconds for small scenes (2 leaves)
– 10 minutes for complex scenes
• the new model is a fast approach… though it is not physically correct
• rendering time between
– some seconds for small scenes (2 leaves)
– 10 minutes for complex scenes
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ResultsResultsResultsResults
• A simple plant…• A simple plant…
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ResultsResultsResultsResults
• A collection of different plants…• A collection of different plants…
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ResultsResultsResultsResults
• A tree…• A tree…
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ResultsResultsResultsResults
• Animations…• Animations…
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Future worksFuture works
• improve rendering of larger plants (trees)
• full support of global illumination
• hardware oriented approximation
• improve rendering of larger plants (trees)
• full support of global illumination
• hardware oriented approximation
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That‘s it...That‘s it...
Thank you for your attention!Are there questions?