How to run your Python code in unity

Python is one of the top 10 popular programming languages of 2022. It is a general-purpose high-level programming language. You can use Python for developing desktop GUI applications, and web applications. Also, you can use Python for developing complex scientific and numeric applications. Python is designed with features to facilitate data analysis and visualization.

Currently, Unity 3D developers used to code in C# because Unity 3D supports C# by default. But python is known for simplicity and is rich in library support for data science. Today we are going to run our python codes in Unity 3D.

Getting Started

There are different ways to integrate python into Unity. Here we are going to explore python integration in two ways.

1. Unity Python Package

UnityPython is a plugin for Unity3D that provides support for running Python 2.x code in Unity3D on any platform which supports System.Reflection.Emit

Requirements

The build target must support System.Reflection.Emit. Here is a chart of platform support for the same.

Setup

Download IronPython dll files and place them into Assets/Plugins directory.

Releases · exodrifter/unity-python

Then, go to Edit > Project Settings > Player > Other Settings > Configuration and change Api Compatability Level to .NET 4.x

Sample Program

Assume you have a small code snippet test.py in Python like this:

import random
class Test():
 def __init__(self, name):
  self.name = name
 def display(self):
  return "Hi, " + self.name
 def random_number(self, start, end):
  return random.randint(start, end)

You can use it from C# like this

var engine = Python.CreateEngine ();
ICollection<string> searchPaths = engine.GetSearchPaths ();
//Path to the folder of test.py
searchPaths.Add (Application.dataPath);
//Path to the Python standard library
searchPaths.Add (Application.dataPath + @"\StreamingAssets"  + @"\Lib\");
engine.SetSearchPaths (searchPaths);
dynamic py = engine.ExecuteFile (Application.dataPath + @"\StreamingAssets" + @"\Python\test.py");
dynamic test = py.Test ("Codemaker");
greeting.text = "Greeting: " + test.display ();
randomNumber.text = "Random Number: " + test.random_number (1, 5);

Output

2. Python for Unity 2.0.1 preview package

Python for Unity is an experimental feature that helps you to integrate python code into your unity project seamlessly. It allows access from Python to the full C# API of UnityEngine, UnityEditor, as well as running Python code from your C# script.

Python for Unity

Requirements

• Python 2.7.5 (64 bits) or later. The package does not work with Python 3.
• Unity 2019.3+. We recommend installing the latest version of Unity 2019 via the Unity Hub

Windows

• You must use Windows 10, patched to build 1803 or later.
• Install the software listed above in the default locations. When installing Python, make sure to check the option to add to the path is on.

Setup

Python for Unity requires some manual installation:

1. First, follow the installation instructions in the manual
2. Next, install Python for Unity itself: Edit your Unity manifest.json file (in the Packages folder of your project) so that it starts with

{
  "dependencies": {
    "com.unity.scripting.python": "2.0.1-preview.2",
    ...
  }
}

Sample Program

Create a script named HelloWorld.cs and attach it to the Main Camera.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class HelloWorld : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        Debug.Log("Unity: Hello World");
        print ("Python: Hello World");
    }
    // Update is called once per frame
    void Update()
    {
    }
}

Output

Also, you can try like this,

• Run your application.
• Go to Window -> General -> Python Console
• Type the following code in the bottom window and click on the Execute button:

import UnityEngine
print ("Python: Hello World from python console")
UnityEngine.Debug.Log("Unity: Hello World from unity console")

Output

The main disadvantage of this package is that it supports only on Unity Editor. It won’t add any builds.

There you have it! Your own Unity app with python support :)

Thanks for reading this article.

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If you are interested in further exploring, here are some resources I found helpful along the way:

GitHub - codemaker2015/Unity-Python-Demo: A demo program to illustrate python code usage in unity

GitHub - codemaker2015/python-for-unity-demo: Python for unity demo