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CityEngine is a 3D city modeling software for urban design, visual effects, and VR/AR production. With its C++ SDK you can create plugins and standalone apps capable to execute CityEngine CGA procedural modeling rules.



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CityEngine SDK

This is the official site for the SDK of CityEngine, a 3D city modeling software for urban design, visual effects, and VR/AR production. Using the CityEngine SDK, a number of open source plugins and APIs have been built, allowing to integrate CityEngine technology into other tools.

The CityEngine SDK can be used for the development of:

  1. Custom importers and exporters for CityEngine.

    This means the SDK enables you to develop CityEngine plugins to read or write additional 3D and image formats or your own proprietary 3D data format. A simple use case example is 3D printing where the STL geometry format is often needed. STL support is not provided out-of-the-box in CityEngine, but you can develop your own STL exporter as described below.

  2. 3D apps which need a procedural geometry engine.

    The core of CityEngine is its unique geometry generation engine, called Procedural Runtime (PRT). PRT takes as input an initial geometry and then applies a given rule package (= CGA rules authored in CityEngine) to generate more detailed 3D geometry as output. For example, PRT can generate - based on given rules - a 3D model of a building out of a parcel polygon. With the SDK you can integrate PRT in your own 3D applications taking full advantage of the procedural geometry generation without running CityEngine. An interesting use case example is Palladio, a plugin for SideFX’s Houdini software. Palladio includes PRT and therefore extends Houdini with the procedural geometry engine of CityEngine. Another use case example could be a specific cultural heritage 3D application which automatically generates detailed 3D models of temples based on input attributes.

This document explains how to install the CityEngine SDK and how to work with the source-code examples contained in this repository. The CityEngine SDK is packaged into three parts:

  1. This git repository with the example sources.
  2. An archive per platform with the SDK binaries and offline documentation. The archives are attached to the releases.
  3. An archive with example data (e.g. rule packages and initial shapes), attached to the releases as well.

Quick Start

  1. Clone or download this repository.

  2. Download the example data and unpack it into a data directory next to examples inside the repo:

  3. Continue with building and running the prt4cmd example for either Windows or Linux. This will automatically download the SDK archive for your platform.

Table of Contents


You can manually download the SDK archive, the open-source examples in this repository and the example data from the Assets section on the Releases page.


This repository contains a number of source code examples in the examples directory. Each example contains a platform-specific README with detailed instructions how to build and use it:

  • prt4cmd: a simple command line utility to apply rule packages onto initial shapes and generate models.
  • stlenc: demonstrates how to write a custom encoder (exporter), in this case for the STL geometry format.
  • stldec: demonstrates how to write a custom decoder (importer) for the STL geometry format.


Read the whitepaper and the architecture overview pdfs or browse the online reference. There is also an offline version in the downloaded sdk archive (/doc subdirectory).

Related Software Products

  • Overview
  • PyPRT: Python language bindings for the Procedural Runtime (PRT)
  • Palladio: CityEngine plugin for SideFX Houdini
  • Puma: CityEngine plugin for McNeel Rhino3d
  • Serlio: CityEngine plugin for Autodesk Maya
  • Vitruvio: CityEngine plugin for Epic Unreal Engine

General Software Requirements

Please note that the individual example READMEs may include further requirements.

All Platforms

  • To load custom encoders built with the latest SDK, CityEngine 2022.1 is required. For older versions of CityEngine an older version of the SDK might have to be used, see Release History. Some SDK versions don't have a matching CityEngine.
  • A license for the corresponding CityEngine version. For example, a license for CityEngine 2022.1 to author Rule Packages for the current SDK release.
  • CMake 3.3 or later (


  • Windows 8.1, 10 or 11 (64bit)
  • Required C++ compiler: Visual Studio 2019 with Toolset MSVC 14.27 or later
  • Required flags for extension libraries release mode: /std:c++17 /bigobj /GR /EHsc /MD (use /MDd to debug)


  • RedHat Enterprise Linux 7.x, 8.x or compatible
  • Required C++ compiler: GCC 9.3 or later (RedHat Enterprise Linux DevToolSet 9)
  • Required flags for extension libraries: -std=c++17 -D_GLIBCXX_USE_CXX11_ABI=0 -march=nocona -fvisibility=hidden -fvisibility-inlines-hidden -Wl,--exclude-libs,ALL

Release History and Changelog

A detailed list of changes to the API, CGA language and built-in codecs can be found in the Changelog.

CityEngine Resources

Issues and Contributions

Did you find a bug or do you want to request a new feature? Please let us know by submitting an issue. Anyone and everyone is welcome to contribute and to extend and improve the examples by sending us pull requests.


The CityEngine SDK is free for personal, educational, and non-commercial use. Commercial use requires at least one commercial license of the latest CityEngine version installed in the organization. Redistribution or web service offerings are not allowed unless expressly permitted.

The CityEngine SDK is licensed under the Esri Terms of Use: