(create_animation)=

# How to watch animation

To watch each phonon mode, v_sim is recommended. The file `anime.ascii` is
supposed to work with v_sim version 3.51 or later. An example how to watch
phonon modes at a **q**-point is shown as follows.

First, you need to create a phonopy input file with, e.g., `ANIME = 0.5 0.5 0`.
After running phonopy with this input file, you get `anime.ascii` that contains
all phonon modes at the **q**-point. Then start v_sim

```bash
% v_sim anime.ascii
```

After opening the graphical user interface, you can find a tab called
**Phonons**. There you can see the phonon modes at the **q**-point that you
specified in the phonopy input file. Then select one of the phonon modes and
watch by pushing the play button. Because only the unit cell shows up at the
start of v_sim, if you want to watch a phonon modulation with a longer period,
then change the values of **Expand nodes** in the **Box and symmetry** tab
(http://inac.cea.fr/L_Sim/V_Sim/user_guide.html#trans). This is especially
important when you choose a **q**-point other than the {math}`\Gamma`-point.

V_sim has a good graphical user interface and also a lot of command line
options. To read the manual well and to check the command line options help you
to use v_sim comfortably, e.g.,

```bash
% v_sim -w oneWindow anime.ascii -x 1:1:0 -t 0.5:0.5:0.5
```
