


Quick Start¶
You can find here basic guides and procedures for using OpenAlea with instructions on how to develop your own package.
Installation¶
For general information about installation, please read Installation Guide.
If you are looking for a specific package installation, refer to the package documentation in Packages.
Tutorials and Gallery¶
You can find examples of what can be done with OpenAlea, you can check the Tutorials and Gallery pages.
Packages¶
Packages page also contains brief presentations of official and available packages.
Development¶
If you want to contribute to the project, you are welcome. See the Development page for more information.
User Guide¶
Models under OpenAlea are in the form of components that could be used as such, or combined together to build user-customised applications. OpenAlea provides two different ways to interacts with components:
- by visual programming, using Visualea
- by writing scripts, using a standard python development environment
Both methods allows you to save your application and run it routinely in batch mode. Visual programming is easier to start with, and it allows you to rapidly discover components of a package. Python scripting allows for programming more complex tasks, and provides an access to additional functionalities of models, by importing python modules that compose them.
Visual Programming¶
OpenAlea provides an high level visual programming interface Visualea.
The main documentation is on Packages at Visualea.
Tutorials have been made on Visualea. You can find them on Tutorials.
Python Scripting¶
OpenAlea packages are available under the python scripting language. This allows to use the components of packages (as in visualea), but also to directly import python modules and get access to all functionalities documented in package’s API.
Using Python¶
Python is a scripting language widely spread in the scientific community. It has a lot of advantages :
- It is easy to learn, even for non programmers.
- It is an high level language, based on the object paradigm
- It is extensible with external libraries
- Multi-platform (Linux, Windows, Mac)
You can learn the basics with the Official Tutorial
Python scripts could be launched by invoking python from a command line:
python myScript.py
You can also launch a Python interpreter and run or test your script step by step.
The default interpreter could be launch by typing python in a terminal (Linux, Mac) or in a DOS windows. Under Windows, you may also use one of the following method:
- Use Start Menu -> openalea -> python shell
- You can use the default python interpreter GUI : IDLE (start menu -> Python 2.4 -> IDLE)
You can also use more ergonomic user interface, like ipython, that provides usefull functionalities (completion, coloration, execution of block of lines,…)
Importing OpenAlea Modules¶
The magic line which will make available all openalea modules is:
import openalea
All OpenAlea modules are available in the openalea namespace. Refer to the modules documentation to learn how to use them.
You can also write simple python scripts in order to execute the same code several times.
Installation¶
Conda Installation¶
Conda is a package manager that can be installed on Linux, Windows, and Mac. If you have not yet installed conda on your computer, follow these instructions : Conda Installation.
OpenAlea Installation¶
The recommended way to install OpenAlea is to create a new conda environment.
First, create an environment named openalea:
conda create -n openalea -c openalea openalea.<package_name>
Here is an example if you want only PlantGL, lpy, MTG and Caribu:
conda create -n openalea -c openalea openalea.plantgl openalea.lpy openalea.mtg alinea.caribu boost=1.66
Activate the openalea environment:
conda activate openalea
In this environment, you may also want to install other Scientific Python packages:
conda install notebook=5.4 matplotlib pandas
In the documentation of each package, a installation procedure is described.
Application Domains¶
Tutorials¶
Here are some interactive tutorials that can help you in your projects.
Using Visualea : Beginning¶
Here is a tutorial in which you will see how to implement a simple modeling problem in Visualea

Here is what you need for the following tutorial
conda create -n visualea_tuto -c openalea openalea.visualea openalea.components openalea.plantgl boost=1.66 -c openalea/label/unstable
conda activate visualea_tuto
Once you installed and activated the OpenAlea environment (see Installation), execute this
visualea
The Goal¶
We measured some tree data and saved these in a tabbed editor (like Excel). The data has been exported in a CSV file. We want to have a simple 3D representation of the measured tree.
Here is the data :
X | Y | crown_up | crown_bot | trunk_diameter |
---|---|---|---|---|
0 | 0 | 10 | 20 | 2 |
10 | 12 | 12 | 18 | 3 |
20 | 22 | 8 | 23 | 3.4 |
0 | 18 | 14 | 22 | 2.5 |
You may want to download the CSV file.
Step 1 : Create Your Own Package¶
First of all, we need to create a package where to put your work (dataflow, node definition, data, …). A package is in fact a simple directory containing python files.
Create a package¶
- Select Package Manager -> Add -> Package
- Fill the form :
- Name : standbuilder
- Description : build stand representation from measured data
- Version : 0.1
- License : Cecill-C
- Authors : All collaborators and package writer
- Institutes : …
- URL : …
- Path : /home/myhome/openalea_pkg (could be anywhere you want)
- Click “OK”

Your new package should appear in the package manager.
Tip
The path corresponds to the directory where the python file will be written. Choose it carefully in order to be able to find it later.
Step 2 : Read CSV Data¶
Create a dataflow to read and view a file¶
Tip
Leaving the cursor on any item in the Package Manager, or on nodes or ports in the dataflow view brings up a tooltip. Clicking on them also shows some documentation in the “Help” tab (bottom-left-hand corner).
In the Package Manager tab (left column), open the openalea.file folder. You should see a list of nodes.
Note
You can search for a particuliar node in the Search tab.
In the Package Manager tab, drag the
read
node from the openalea.file package to the workshop. It should now appear on the canvas.In the workspace, right click on the
read
node and choose “Open Widget”. Then browse for the “stand.csv” file (no need to validate anything, changes are automatically taken into account so you can simply close the window).Drag the
text
node from the openalea.data structure.string folder onto the workspace.Connect the output of the
read
node to the input of thetext
node.

View the file contents¶
- Right click on the
text
node and select “Run” - Right click on the
text
node and select “Open Widget”
Build a CSV object¶
In order to manipulate the CSV data, we are going to build a CSV object.
- Select the search tab in the package manager
- Type CSV
- Drag the
read csv
node on the workspace - Do the same to create a
getitem
node (openalea.python method.getitem
) - Connect
read
’s output toread csv
’s input - Connect
read csv
’s first output togetitem
’s first input - Add an
int
node on the workspace, and connect its output to the second input ofgetitem
- Execute the graph by selecting “Run” in the context menu of the
getitem
node - Print the output in the shell : Right click on the output port, and select “Print”

Save your work¶
- Select File -> Save as composite node (CTRL + S)
- In the selector dialog, click “New” Button
- In the new dialog
- Select the standbuilder package in the combo box
- Enter the name : readcsv_1
- Add a description : Read data file
- Click “Ok”
- In the selector, click “Ok” button
- The new graph should appear in the standbuilder package.

Step 3 : Create a simple 3D representation of one tree¶
Before displaying the whole stand, we must rebuild a tree. In this tutorial we build a very simple tree representation composed by a sphere for the crown and a cylinder for the trunk.
Create a 3D object¶
This simple dataflow shows how to display a scene object.
- First step, we create a new workspace : Select File -> New Empty Workspace (CTRL+T)
- Create the following dataflow by using PlantGL nodes
vplants.plantgl.objects.cylinder
creates a cylindervplants.plantgl.objects.translated
moves the input objectopenalea.data structure.tuple.tuple3
to set the translation vectorvplants.plantgl.visualization.plot3d
to view the resultopenalea.data structure.float
to set the parameters of the tuple3 node
Create a simple tree¶
To build our tree, we must construct a PlantGL scene containing a cylinder and a sphere.
- Modify the previous dataflow as follow:
- Add a
vplants.plantgl.objects.sphere
object - Add a
vplants.plantgl.objects.translated
object - Add a
vplants.plantgl.objects.scene
object - Connect the 2 translated objects to a
vplants.plantgl.objects.scene
object
- Add a
- Save this dataflow in your standbuilder package as simple_tree
Step 4 : Create a Macro Node / Group Nodes¶
We will need to use the previous dataflow to build trees. To simplify this procedure, we would like to use a simple node and not a complex dataflow. For that we are going to embed the previous dataflow in a composite node (also named macro node).
Transform simple_tree to a reusable composite node¶
Select simple_tree in the package manager
Right click on the simple_tree graph, select “Properties” and click on the “Inputs / Outputs” button
Add 5 inputs with the + button :
- X - IInt - 0 - X position
- Y - IInt - 0 - Y position
- crown_up - IFloat - 16.0 - Top of the crown
- crown_bot - IFloat - 8.0 - Bottom of the crown
- trunk_dia - IFloat - 3.0 - Trunk diameter
Add 1 output with the + button
- scene - None - PlanGL scene
Click “OK” and the buttons will appear in the workshop
Modify the graph as follow
- Connect input 0 and 1 to the X and Y nodes
- Connect input 2 and 3 to a minus node
openalea.math.-
, and connect the result to the crown radius - Connect input 5 to the trunk radius
- Connect input 3 to the crown bottom
Save your work as a new composite node in standbuilder named tree_scene
Using the new composite node in a dataflow¶
- Open our first dataflow readcsv_1 in the standbuilder package (doubleclick)
- Drag the node
standbuilder.tree_scene
on the new workspace - Add 5x
getitem
and 5xstring
object - Connect the nodes as the picture in order to retrieve to different object properties
- Add a
plangl.visualization.plot3D
object and connect it to the output oftree_scene
- Run the dataflow several times and change the value of the first
getitem
(object index) - Save the dataflow in the standbuilder package as readcsv_2
Create a composite node by grouping nodes¶
- Select the 5
getitem
and their associatedstring
object - Click on Menu Workspace -> group (CTRL+G)
- Run the dataflow
- Save it in the standbuilder package as readcsv_3
Step 5 : Get the spatial distribution of the trees¶
We want to extract from the csv object the X and Y properties and plot them in 2D.
Extract data¶
- Create a new workspace (CTRL+T)
- Add a
read
node and aread csv
node to read a csv file - Set the file to read by opening the
read
widget (Open Widget) - Run and display the output (output port context menu -> Print or Tooltip) : it’s a list of obj
- Add a
getitem
node and anint
node to select an object in the list - Add an
extract
node and 2string
nodes to select properties in a particular object - Set the 2
string
objects to X and Y - Run and display the output (output port context menu -> print or tooltip) : it’s a list containing the X and the Y properties of the selected object.
Implement iterative process¶
We want to do the same thing, but for all the CSV objects contained in the file.
- Remove the
getitem
and theint
nodes (with suppr) - Add an
openalea.function operator.map
- Connect the output of
extract
to the first input ofmap
- Connect the output of
read csv
to the second input ofmap
- Add an
openalea.flow control.X
node and connect its output the first input ofextract
- Run the
map
object and display the result
Note
The X object represents a function variable. The map apply a function to each element received in its second input.
Plot 2D¶
- Add the nodes
openalea.plottools.VS Plot
andopenalea.plottools.tuples2seq
on the workspace - Connect the
map
output the input oftuples2seq
and the last output theVS Plot
node. - Run the dataflow
- Save it in the standbuilder package as plot_csv
Step 6 : Apply the process to multiple trees¶
In this step, we used the same method to build the entire stand
- Open the
readcsv_3
dataflow - Modify it in order to plot in 3D all the tree contained in the file and not only one
- Use a
openalea.flow control.X
node and aopenalea.functional.map
node - Save this work in your standbuilder package as plot_stand
Using Visualea : Weberpenn¶

Context¶
In OpenAlea, different tree architectures can be generated procedurally.
OpenAlea.WeberPenn
is based on the tree generating algorithm defined by Weber and Penn in 1995.
The model generates a tree structure based on a set of allometric rules. Fundamental parameters are, for instance, the overall appearance of the tree, the size of the lower part of the tree without axes, the max branching order or the curvature of the axes.
Install¶
Install Visualea and Weberpenn for this tutorial
conda install -c openalea openalea.weberpenn openalea.visualea
Then, execute this
visualea
Model Parameters¶
Image Courtesy of Wolfram Diestel, developer of the Arbaro software.
- General shape parameters :Scale and ScaleV : Global size of the treeBaseSize - Size of the lower part of the tree without branches
Each other parameters are defined for each branch level (or order) with order0 = trunk
Branch length is specified by the user at each order and is relative to the father branch length and to the overall shape of the tree.
rotation (aka rotationV) define the phyllotaxis angle at each order
- curve parameter defines curvature of branchescurve back define inflexion angle
down_angle define the angle of insertion between a branch and its father
Begin with weberpenn¶
Once you’ve launched Visualea, in the package manager, go in demo and double-click on demo_WeberPenn
.

Workflow 1¶
On this workflow, there are the global parameters
, trunk
, order 1
, order 2
, tree parameters
,
weber and penn
and plot3D
nodes. You can change some parameters by double-clicking on the nodes.
Global parameters
change main parameters of the tree like its shapetrunk
,order 1
andorder 2
allow to change parameters of the current ordertree parameters
synthesizes all the parameters into a unique global parameters objectweber and penn
computes the scene with all the generated surfacesplot3D
displays a 3D-scene
Right-click on the plot3D
node and click on “Run”. The scene will appear and you’ll be able to see the
tree architecture corresponding to the inputs you’ve entered in the parameters nodes
Tip
You may want to change some parameters and see the impact on the tree architectures in real time.
To do this, right-click on the plot3D
node and click on “Mark as User Application” then run the node.
Now, when you change a parameter, the scene updates instantly. Have fun !!!

Workflow 2¶
On this workflow, it is the same as the Workflow 1 but you only have to choose the species you want in the
species
node. There are 3 species that have been preset.

Gallery¶
Packages¶
Index
Name | Stars | Contributors | Downloads | License | Docs | Conda | |
---|---|---|---|---|---|---|---|
core |
|
|
|
|
|
|
|
eartrack |
|
|
|
- |
|
|
|
hydroshoot |
|
|
|
- |
|
|
|
lpy |
|
|
|
|
|
|
|
mtg |
|
|
|
|
|
|
|
phenomenal |
|
|
|
- |
|
|
|
plantgl |
|
|
|
- |
|
|
|
visualea |
|
|
|
- |
|
|
|
weberpenn |
|
|
|
- |
|
|
Modelling with OpenAlea¶
MTG¶
Multiscale Tree Graph datastructure and interfaces

MTG package aims to define :
- A share data structure for plant architecture representation.
- Read and write MTG files.
- Export to various graph format.
- Several algorithms for MTG.
Authors : Christophe Pradal, Christophe Godin
Institutes : Cirad, Inria
Source Code : Github
L-Py¶
Plant simulation using Lindenmayer Systems with Python

L-systems were conceived as a mathematical framework for modeling growth of plants. L-Py is a simulation software that mixes L-systems construction with the Python high-level modeling language.
Authors : Frédéric Boudon, Christophe Pradal, Thomas Cokelaer, Przemyslaw Prusinkiewicz, Christophe Godin
Institutes : Cirad, Inria, U. Calgary
Citation : Boudon et al., 2012, https://doi.org/10.3389/fpls.2012.00076
Source Code : Github
PlantGL¶
An open-source graphic toolkit for the creation, simulation and analysis of 3D virtual plants

Authors: Frédéric Boudon, Christophe Pradal, Christophe Nouguier, Jérôme Chopard, Christophe Godin
Institutes : Cirad, Inria
Citation : Pradal, Boudon et al., 2009, https://doi.org/10.1016/j.gmod.2008.10.001
Source Code : Github
OpenAlea Framework¶
OpenAlea Framework is able to discover and manage packages and logical components, build and evaluate dataflows and Generate final applications

Authors : Christophe Pradal, Samuel Dufour-Kowalski, Frédéric Boudon, Christian Fournier, Christophe Godin
Institutes : Cirad, Inria, INRA
Citation : Pradal et al., 2008, https://doi.org/10.1071/FP08084
Source Code : Github
Plant Models¶
WeberPenn¶
An extension of the Weber & Penn model for OpenAlea

Authors : Christophe Pradal
Institutes : Cirad
Original Article : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.380.2046
Source Code : Github
Plant Biophysics¶
Hydroshoot¶
Hydroshoot model for 3D hydraulic architecture simulation

HydroShoot is a functional-structural plant modelling package taking into account hydraulic architecture and leaves energy budget and gas exchange.
Authors : Rami Albasha, Christian Fournier, Christophe Pradal
Institutes : INRA, Cirad
Citation : Albasha et al., 2019, https://doi.org/10.1093/insilicoplants/diz007
Source Code : Github
Phenotyping¶
Phenomenal¶
3D reconstruction from high-throughput plant phenotyping images

Plant high-throughput phenotyping aims at capturing the genetic variability of plant response to environmental factors for thousands of plants, hence identifying heritable traits for genomic selection and predicting the genetic values of allelic combinations in different environments.
Authors : Simon Artzet, Christian Fournier, Christophe Pradal, Nicolas Brichet, Jerome Chopard, Michael Mielewczik
Institutes : INRA, Cirad
Source Code : Github
EarTrack¶
EarTrack is an imaging library to detect and track future position of ears on maize plants

Authors : Nicolas Brichet, Christian Fournier, Simon Artzet, Christophe Pradal,
Institutes : INRA, Cirad
Citation : Brichet et al., 2017, https://doi.org/10.1186/s13007-017-0246-7
Source Code : Github
Development¶
Contents
Contributing¶
Introduction¶
OpenAlea is open-source. Everyone is welcome to contribute.
Note
All the packages are separated on two Github pages
- the official and stable packages on OpenAlea
- the unofficial, WIP and to be reviewed packages on OpenAlea-Incubator
There are many ways to contribute to OpenAlea. The most common ways of contributing are coding or documenting different parts of the project. One may improve documentation which is as much important as improving the code itself. One could also create their own package, see How to contribute.
Another way to contribute to the project is to report bugs ans issues you are facing.
How to contribute¶
The main way to contribute is to fork the package repository you are interested in on GitHub
Note
Remember, the packages are found on different GitHub pages. The following steps describe a tutorial for an OpenAlea package. Make the good changes if you want to use OpenAlea-Incubator packages.
Create an account on GitHub if you do not already have one. You will choose your GitHub login <your_login>.
Fork the package repository of your choice (for instance, MTG repository) and click on the ‘Fork’ button near the top of the page. It generates a copy of the repository under your account on the GitHub user account. For more details on how to fork a repository see this guide.
Clone your fork of the package repo from your GitHub account to your local disk
git clone https://github.com/<your_login>/<package_name>.git cd <package_name>
Create a branch <branch_name> to hold your development changes
git checkout -b <branch_name>
and start making changes. Always use a
feature
branch. It’s good practice to never work on themaster
branch!Note
In the above setup, your
origin
remote repository points to<your_login>/.git
. If you wish to fetch/merge from the main repository instead of your forked one, you will need to add another remote to use instead oforigin
. It’s good practice to choose the nameupstream
for it, and the command will be:git remote add upstream https://github.com/openalea/<package_name>.git
If the package you chose come from OpenAlea-Incubator, the command will be:
git remote add upstream https://github.com/openalea_incubator/<package_name>.git
And in order to fetch the new remote and base your work on the latest changes of it you can:
git fetch upstream git checkout -b <your_name> upstream/master
Develop the feature on your feature branch on your computer, using Git to do the version control. When you’re done editing, add changed files using
git add
and thengit commit
files:git add <modified_files> git commit -m "description of what you've done"
to record your changes in Git, then push the changes to your GitHub account with:
git push -u origin <branch_name>
Once you’ve finished, you can create a pull request on the corresponding GitHub. Follow these instructions to create a pull request from your fork.
Documentation¶
You can also contribute to the documentation. If you find some parts that are not explained enough or uncleared, you can complete or improve the documentation.
Once you have forked the package on your device, you have to install Sphinx to generate the HTML output
pip install sphinx
In each package repository, it must be a docs/
directory in which the reStructuredText documents are. You are pleased
to modify or create these and generate the HTML output in the docs/
directory
make html
Note
If you are creating your own package, you can build the Sphinx environment directly in the docs/
directory
sphinx-quickstart
Once you are finished, you can add, commit and push what you have done on GitHub and then create a pull request (see How to contribute).
As we want all the documentation to look the same way, configure your Sphinx like us:
The theme we are using is the Read the Docs Sphinx Theme. The theme can be installed like this
pip install sphinx_rtd_theme
Once you’ve installed the theme, write in your
conf.py
filehtml_theme = "sphinx_rtd_theme"
Then write in the same file
html_theme_options = { 'logo_only': True }
Download the OpenAlea logo and put it your
_static
directory and then write in yourconf.py
filehtml_static_path = ['_static'] html_logo = "_static/openalea_web.svg"
Mention the main website “openalea.rtfd.io”
License¶
- The OpenAlea core is released under the Cecill-C license.
- The OpenAlea GUI, Visualea, is released under the Cecill-v2 license.
Note
Each external package can have its own license, please check it before using a package.
You can refer to the document Package License Guidelines for futher explanations.
Please, cite the project if you use OpenAlea in your publications.
Help¶
Need help ? Want to contact someone ? Contact prenon.nom@machin.fr.