# ALICE Open Data Blender animation

## Project Description

This project has the purpose of generating a 3D animation of an ALICE particle collision event, inside the LHC, using data obtained from CERN's Open Data Portal, which makes ESDs - Event Summary Data files, that contain information about such events - open and available for analysis.

ESD files regarding the ALICE experiment can be found on http://opendata.cern.ch/search?page=1&size=20&experiment=ALICE, and they should be processed using the Aliroot software, as indicated in the 'Aliroot' section below.

// AliESD_Example git repository: https://git.cta.if.ufrgs.br/ALICE-open-data/AliESD_Example/tree/Blender_animation

The software that makes the animation is Blender, which is free and open source. Blender's 2.79b version should be downloaded for this project, and can be found on https://www.blender.org/download/releases/2-79/

Before starting, you must also clone this repository:
```bash
mkdir -p ~/alice
cd ~/alice
git init
git clone https://git.cta.if.ufrgs.br/ALICE-open-data/alice-blender-animation.git
```

The animation making can be summarized in three basic steps:

1) Downloading an ESD file;
2) Installing aliRoot and running macros;
3) Run bash to generate Blender animation using the ESD processing results.

## Step 1 - Downloading ESD files

ESD files regarding the ALICE experiment can be found on http://opendata.cern.ch/search?page=1&size=20&experiment=ALICE. If you have doubts on which file to pick for a test, you can select any file on this list: http://opendata.cern.ch/record/1102.

You must save your ESD file inside the 'aliRoot' directory, which is obtained by cloning this repository as mentioned above.

## Step 2 - Installing aliRoot

1) Install aliBuild. Follow instructions on https://alice-doc.github.io/alice-analysis-tutorial/building/custom.html

2) Initialize AliPhysics

```bash
cd ~/alice
aliBuild init AliPhysics@master
```
3) Verify dependencies (Optional)

```bash
$ aliDoctor AliPhysics
```
4) Build AliPhysics with aliroot5 (this may take a long time)
```bash
aliBuild build AliPhysics --defaults user -z aliroot5
```
5) Enter AliPhysics environment
```bash
alienv enter AliPhysics/latest-aliroot5-user
```
6) Run the macro

```bash
cd ~/alice/alice-blender-animation/aliRoot
aliroot runAnalysis.C
```
Results will be saved on three text files: `s-esd-detail.dat`, for an event with a 'small' number of tracks; `m-esd-detail.dat`, for an event with a 'medium' number of tracks; `l-esd-detail.dat`, for an event with a 'very large' number of tracks. You must then move those three files to the 'animate' folder, where the Blender scripts are.


## Step 3 - Generating animation

Run the script animate_particles.py as in the example below:

blender -noaudio --background -P animate_particles.py -- -radius=0.05 -duration=1 -camera="BarrelCamera" -datafile="esd-detail.dat" -simulated_t=0.02 -fps=24 -resolution=100

In the example above, argument 'radius' has value 0.05, 'duration' has value 10 and so on.
-radius:
particle radius; must be a number; type float
-duration:
animation duration; must be a number; type int
-camera:
defines animation view; must be a string; available options: OverviewCamera, BarrelCamera, ForwardCamera
-datafile:
filename for event data file; must be a string; must be one of your text files: `s-esd-detail.dat`, `m-esd-detail.dat`, `l-esd-detail.dat`
-simulated_t:
simulated time of event; must be a number; type float
-fps:
frames per second; must be a number; type int
-resolution:
animation resolution percent; must be a number; type int

Animation will be saved in format .mp4 on the address `/tmp/blender`