Prerequisities

Install CMake (version 3.15 or newer) from https://cmake.org/install/
Install Xcode 11.3 from https://developer.apple.com/xcode/resources/
For best JPEG-decoding performance, you must have nasm installed so that CMake can find it. Everything will work fine without it, just slower.
Install the Unreal Engine (version 4.26 or newer) from https://www.unrealengine.com/en-US/download

Cloning the git repos

The following illustrates the recommended directory layout for developers:

~/dev - Your own root directory for development.
~/dev/cesium-unreal-samples - The directory for the Unreal project that will use the plugin.
~/dev/cesium-unreal-samples/Plugins/cesium-unreal - The directory for the actual Cesium for Unreal plugin.
~/dev/cesium-unreal-samples/Plugins/cesium-unreal/extern/cesium-native - The directory for the base libraries project.

You may use any directory for the project, but the directory for the actual Cesium for Unreal plugin MUST be in a subdirectory Plugins/cesium-unreal of the project directory. This way, Unreal will automatically find the Plugin when running the project, and pick up any changes that have been made to the plugin.

This can be set up with the following sequence of commands, on the console, starting in the ~/dev directory:

git clone https://github.com/CesiumGS/cesium-unreal-samples.git
cd cesium-unreal-samples
mkdir Plugins
cd Plugins
git clone --recursive https://github.com/CesiumGS/cesium-unreal.git

Note: The last line will also check out the cesium-native submodule and its dependencies. If you forget the --recursive option, you will see many compiler errors later in this process. If this happens to you, run the following in the Plugins\cesium-unreal directory to update the submodules in the existing clone:
git submodule update --init --recursive

Building cesium-native

The cesium-native libraries and their dependencies use CMake and must be built separately from Cesium for Unreal. There are a number of ways to do this, but typically on macOS.

CMake command-line

First, configure the CMake project in the ~/dev/cesium-unreal-samples/Plugins/cesium-unreal/extern directory by following the instructions below.

Note: The following steps must be done in the extern directory, and not the cesium-native subdirectory!

Change to the ~/dev/cesium-unreal-samples/Plugins/cesium-unreal/extern directory, and execute the following commands to build and install a Debug version of cesium-native:

cmake -B build -S . -DCMAKE_BUILD_TYPE=Debug

cmake --build build --target install

To build a Release version, do the following:

cmake -B build -S . -DCMAKE_BUILD_TYPE=Release

cmake --build build --target install

CMake command-line for iOS

Note: It is recommended that the build steps for CMake command-line for macOS (above) be completed first. Unreal Engine Editor will not launch without the host side binaries compiled as well.

Configure the CMake project in the ~/dev/cesium-unreal-samples/Plugins/cesium-unreal/extern directory by following the instructions below. Use a different build directory than the one use for macOS as this will require compiling for a different architecture.

Note: The following steps must be done in the extern directory, and not the cesium-native subdirectory!

Change to the ~/dev/cesium-unreal-samples/Plugins/cesium-unreal/extern directory, and execute the following commands to build and install a Release version of cesium-native:

cmake -B build-ios -S . -GXcode -DCMAKE_SYSTEM_NAME=iOS -DCMAKE_OSX_ARCHITECTURES=arm64 -DCMAKE_POSITION_INDEPENDENT_CODE=ON -DCMAKE_BUILD_TYPE=Release

cmake --build build-ios --target install --config Release

You can also build and install the debug version by using Debug or RelWithDebInfo instead of Release.

Table of Contents

Prerequisities

Cloning the git repos

Building cesium-native

CMake command-line

CMake command-line for iOS