Catmull Rom#
See [Keys1981].
(1)#\[\begin{split}\phi(t)=\begin{cases}
\frac{3}{2}|t|^3 - \frac{5}{2}|t|^2 + 1, \quad |t| \in [0,1[ \\
-\frac{1}{2}|t|^3 + \frac{5}{2}|t|^2 - 4|t| + 2, \quad |t| \in [1,2] \\
0, \quad \mathrm{elsewhere}
\end{cases}\end{split}\]
