- #1
LostInSpace
- 21
- 0
Hi!
I have a bezier curve defined by:
[tex]
\vec{b}(t) = (x(t), y(t))
[/tex]
where
[tex]
\begin{array}{lcl}
x(t) &=& a_xt^3 + b_xt^2 + c_xt + x_0 \\
y(t) &=& a_yt^3 + b_yt^2 + c_yt + y_0
\end{array}
[/tex]
for [tex]t \in \lbrack 0, 1 \rbrack[/tex]. All constants are computed from vertices on the curve and control points associated with those vertices.
For an arbitrary point [tex]\vec{r}\in\mathbb{R}^2[/tex] I want to find all points [tex]\vec{b}_{t_0}\in\vec{b}(t)[/tex] (if any) that satisfies
[tex]\vec{b}_{t_0} + \nabla\vec{b}(t_0)s = \vec{r}[/tex]
for some [tex]s[/tex].
Not sure I'm correct here, but as fas as I remember, [tex]\nabla \vec{b}(t)[/tex] is the normal to the curve, right?
I don't know how to explain this in a better way...
For any point [tex]\vec{r}[/tex] I want to find all points [tex]\vec{b}(t_0)[/tex] such that the normal to [tex]\vec{b}(t_0)[/tex] intersects [tex]\vec{r}[/tex].
How can I do this?
Thanks in advance,
Nille
I have a bezier curve defined by:
[tex]
\vec{b}(t) = (x(t), y(t))
[/tex]
where
[tex]
\begin{array}{lcl}
x(t) &=& a_xt^3 + b_xt^2 + c_xt + x_0 \\
y(t) &=& a_yt^3 + b_yt^2 + c_yt + y_0
\end{array}
[/tex]
for [tex]t \in \lbrack 0, 1 \rbrack[/tex]. All constants are computed from vertices on the curve and control points associated with those vertices.
For an arbitrary point [tex]\vec{r}\in\mathbb{R}^2[/tex] I want to find all points [tex]\vec{b}_{t_0}\in\vec{b}(t)[/tex] (if any) that satisfies
[tex]\vec{b}_{t_0} + \nabla\vec{b}(t_0)s = \vec{r}[/tex]
for some [tex]s[/tex].
Not sure I'm correct here, but as fas as I remember, [tex]\nabla \vec{b}(t)[/tex] is the normal to the curve, right?
I don't know how to explain this in a better way...
For any point [tex]\vec{r}[/tex] I want to find all points [tex]\vec{b}(t_0)[/tex] such that the normal to [tex]\vec{b}(t_0)[/tex] intersects [tex]\vec{r}[/tex].
How can I do this?
Thanks in advance,
Nille