Script

The script subprogram allows the execution of python scripts. Those scripts are to be written in a blender text block. The scripts written for the script node are slightly different from normal scripts in the following:

  • Inputs added to the node will be initialized as variables. So if one adds an input named count to the node, one can use the variable count in the script like any other variable. See below.

  • Star imports are not allowed due to performance reasons. So something like from random import * will not work.

  • Some python modules and structures are automatically imported so they needn’t be imported when writing the scripts. Those modules include:

    • bpy.
    • sys.
    • itertools.
    • animation_nodes, or AN for short.
    • algorithms, which is short for AN.algorithms.
    • Mathutils structures: Vector, Matrix, Quaternion, Euler.
    • All data structures in AN.data_structures: Vector3DList, Matrix4x4List, MeshData, …

New inputs can be added by using the New Input button. The name of the input will be the name of the variable that is initialized with its value, subsequently, the name of the input has to be unique and follow the same guidelines for naming python variables, that is, starts with a letter or and underscore, must not have white spaces and must not be a python keyword.

New outputs can be added by using the New Output button. The value of the output will be the value of the variable carrying its name at the end of the script, subsequently, the same rules of naming variables apply, it should be noted that the name should be unique of both the inputs and outputs. For instance, if an integer output is added with the name result and the script contains the line result = 5 + 2 then the value of the output is 7.

It should be noted that if the script can be refactored into a single line, it would be better to use the Expression Node directly. Also, note that context sensitive operators can’t be used directly as the context is always the node editor unless your force change it which is not recommended.

Advanced Node Settings

  • Description - A description for the function of the script. This description only appears in the Invoke Subprogram node when choosing the required subprogram, however, it is a good practice to write a description for each subprogram so that other users can understand its function.
  • Interactive Mode - If enabled, Animation Nodes will automatically import changes you make in the text editor. If disabled, a button will appear Import Changes that enables you to import changes manually when needed.
  • Debug Mode - If enabled, errors in the script will be drawn on the node. If disabled, errors becomes fatal and will stop node tree executions until it is resolved.
  • Initialize Missing Outputs - If enabled and outputs are not initialized, that is, no variables with the same name exists in the script, the outputs will get initialized with their default values, avoiding non initialization errors.
  • Correct Output Types - If enabled, Animation Nodes will try to correct the type of outputs and return default value if it couldn’t. For instance, if the an output is of integer type and it was initialized with a float, it will be converted to an integer by flooring.

Examples

Example 1

../../_images/script_example1.png

In this example, the script node just prints Hello World, it doesn’t have any inputs or outputs.

Example 2

../../_images/script_example2.png

In this example, two inputs were given and an output is expected to be initialized. The script initializes the output to the sum of inputs.

Example 3

../../_images/script_example3.png

In this example, the node returns the x resolution of the scene. Notice that we didn’t have to import bpy, because it is already imported, see above.