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8
What is the goal of Subdivision techniques? Explain Subdivision using the Lane-Riesenfeld technique!
We interpret a sequence of points
as the control points of a B-Spline curve
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Now, we want to describe the same curve with a higher number of control points.
We define two operators on the sequence

Doubling
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Averaging
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To determine the new vertex positions, we compute weighted positions based on even / odd rules.
Subdivision Operators
Linear (primal)
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Quadratic Spline (dual)
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Cubic Spline (primal)
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TODO: Fix this explanation
Consider the B-Spline basis function
.
It is a piecewise linear function between
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We can write
as an affine combination of the same function with parameter
:

We can do this for uniform B-Spline basis functions in general:

where
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
Now, we want to describe the same curve with a higher number of control points.
We define two operators on the sequence

Doubling

Averaging

To determine the new vertex positions, we compute weighted positions based on even / odd rules.
Subdivision Operators
Linear (primal)

Quadratic Spline (dual)

Cubic Spline (primal)

TODO: Fix this explanation
Consider the B-Spline basis function

It is a piecewise linear function between
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
We can write
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
We can do this for uniform B-Spline basis functions in general:

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