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60
Name three ways to estimate Form Factors for Radiosity computation!
Sampling
Monte Carlo Sampling: Generate random points
according to a distribution
and evaluate

Nusselt Analogon
Given sender patch with area
.
Project sender patch onto hemisphere of receiving patch:

where
is the angle between sending patch normal and projection direction and
is the distance between the two patches.
Project result into plane:
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The form factor is the covered portion of the unit circle.
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Problem: Assumptions only hold for patches that are sufficiently far away.
Hemicube
Rasterize 5 sides of a hemicube placed around a point on
.
Denote by
the set of pixels that see patch
. Then,

where
are pre-calculated form factors for the individual pixels of the hemicube.
Monte Carlo Sampling: Generate random points

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
Nusselt Analogon
Given sender patch with area

Project sender patch onto hemisphere of receiving patch:

where


Project result into plane:


The form factor is the covered portion of the unit circle.


Problem: Assumptions only hold for patches that are sufficiently far away.
Hemicube
Rasterize 5 sides of a hemicube placed around a point on

Denote by



where

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Flashcard info:
Author: janisborn
Main topic: Informatik
Topic: Computergrafik
School / Univ.: RWTH Aachen
City: Aachen
Published: 18.05.2022