Preparing Open RV on Windows

Open RV 2025 can be built for Windows using the VFX reference platform. Dependencies can be viewed in the cmake/defaults/ folder. eg cmake/defaults/CY2026.cmake

Select your VFX reference platform by clicking on the appropriate tab. Install instructions follows.

  • NOTE: CY2025 and CY2026 are experimental. Noteably CY2026 for RV is still on Qt 6.5.3 pending changes necessary for 6.8.3

Boost               : 1.88.0
Cmake               : 3.31.X+
Imath               : 3.2.2
NumPy               : 2.3.0
OCIO                : 2.5.0
OpenEXR             : 3.4.3
OpenSSL             : 3.6.0
Python              : 3.13.9
Qt                  : 6.8.3 ** RV Still on 6.5.3 pending work
Visual Studio       : 2022 (MSVC v143 14.40.X)

All other dependencies are shared across variations.

Summary

  1. Microsoft Visual Studio

  2. Setup default MSVC compiler

  3. Install Python 3

    1. Copy python.exe and rename it to python3.exe

  4. Install CMake

  5. Install Qt

  6. Install Strawberry Perl

  7. Install Rust

  8. Install MSYS2

    1. Install required MSYS2 pacman packages (from an MSYS2-MinGW64 shell)

  9. Setup environment variables

  10. Build Open RV

Warning

You should be cloning the repository later in the steps, but if you must clone it beforehand, clone it into the root of a drive (e.g. c:). See Get Open RV source code.

1. Microsoft Visual Studio

Warning

Open RV will not compile with Microsoft Visual Studio 2022 version 17.11.X with the default compiler because of issues between PySide2 and that version of the compiler.

You can still install 17.11.X, but you will need to install MSVC v143 version 14.40 to compile Open RV itself and MSVC v143 14.39.X to compile Boost.

Any variant of Microsoft Visual Studio 2022 will work with Open RV (e.g. Enterprise, Professional or Community). You can select the version on the Visual Studio website.

Installation

Note

Quick guide:

  • You must select Desktop Development with C++

  • In the individual components section, you must install MSVC v143 14.40.X for Open RV and MSVC v143 14.39.X to compile Boost.

2. Setup default MSVC compiler

If Microsoft Visual Studio 2022 was installed for the first time (using the steps above), MSVC v143 v14.40 should be the default compiler, although varying setup may affect this.

To ensure compatibility with Open RV, we need to make sure that MSVC v143 v14.40 is the default compiler.

Here are the possible methods to set the default compiler:

Method 1: Check default props file

The first solution is to modify the Microsoft.VCToolsVersion.v143.default.props under C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build. The path will vary depending on whether the variant is Enterprise, Profressional or Community.

Make sure that the VCToolsVersion is set to 14.40.33807. The file should look similar to this:

<?xml version = "1.0" encoding="utf-8"?>
<Project ToolsVersion = "4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$([System.IO.Path]::GetFullPath($(MSBuildThisFileDirectory)Microsoft.VCRedistVersion.v143.default.props))"/>
  <PropertyGroup>
    <VCToolsVersion Condition = "'$(VCToolsVersion)' == ''" >14.40.33807</VCToolsVersion>
  </PropertyGroup>
</Project>

If the version is different, change it to 14.40.33807 in the file.

3. Install Python 3

You must install the Python version corresponding to your chosen VFX reference platform using the official Python installer.

Install Python 3.11.9 using the official Python installer.
On the [Python 3.11.9 page](https://www.python.org/downloads/release/python-3119), scroll down and download the correct version for your Windows. Typically, the correct version will be **Windows installer (64-bit)**.

It is highly recommended that you install this Python in C:\Python311

Python Installation Steps

The carousel below shows how to install Python. The displayed images are from Python 3.11.X, but for VFX-CY2023 the path should be C:\Python310 instead of C:\Python311.

Note

Take note of the installation path for Python 3, as it will be required in a subsequent step.
The recommended path is:

  • C:\Python311 for VFX-CY2024

  • C:\Python310 for VFX-CY2023

3.1 Copy python.exe and rename it to python3.exe

Copy the Python executable as python3.exe to ensure compatibility with Open RV, which requires the python3 command. This also aligns with Linux and macOS conventions, where both python and python3 are valid commands.

4. Install CMake

Warning

Minimum recommended version for CMake is 3.27.X.

Download the lastest version of CMake from the official CMake website. Typically, the correct version will be Windows x64 Installer. Follow the installation wizard prompts to complete the setup. There are no special considerations or unique configuration options required.

Note

Take note of the installation path for CMake, as it will be required in a subsequent step.
The default path is C:\Program Files\CMake.

5. Install Qt

Warning

When obtaining Qt from a third-party source, ensure it includes OpenSSL support and check for the following essential modules that may not be included by default: QtWebEngine, QtWebSockets, QtMultimedia, and QtDeclarative.

For example, Qt from MSYS2 is missing QtWebEngine.

Download the Qt version corresponding to your chosen VFX reference platform from the official Qt website using the online installer. It is recommended to install Qt in a location with a short path length. (e.g. C:\Qt)

Download Qt 6.5.3.
This version should be available in the regular Qt installer without needing archives.

Additionally, ensure you have jom, which is included with Qt Creator, available through the Qt online installer. If you prefer not to install Qt Creator, you can download jom separately from the official Qt repository and copy the executable and supporting files to the Tools/QtCreator/bin/jom directory within your Qt installation.

Installation Steps

For Qt 6.5.3, the installation is more straightforward:

1. **After log in**: Open the setup, log in with your credentials, and proceed through the prompts
2. **Select Qt 6.5.3**: Qt 6.5.3 should be available in the main installer without needing archive packages
3. **Choose components**: Select the MSVC 2019 64-bit component for Qt 6.5.3
4. **Uncheck optional packages**: Uncheck any optional packages you don't need (Android, iOS, WebAssembly, etc.)
5. **Complete installation**: Click 'Next' to proceed with the installation

Warning

The screenshot below represent the installation for Qt 5, but the steps are the same for Qt 6. The only difference is the selection of Qt 6.5.3 instead of Qt 5.15.2 in the fourth screenshot.

Note

Take note of the installation path for Qt, as it will be required in a subsequent step.
Based on the recommendation above, the path would be:

  • C:\Qt\6.5.3\msvc2019_64 for VFX-CY2024

  • C:\Qt\5.15.2\msvc2019_64 for VFX-CY2023

6. Install Strawberry Perl

Download and install the 64-bit version of Strawberry Perl

Note

Take note of the installation path for Strawberry Perl, as it will be required in a subsequent step.
The default path is C:\Strawberry.

7. Install Rust

Warning

Rust version 1.92 or later is required to build certain Python dependencies (such as cryptography).

Install Rust using rustup-init:

  1. Download rustup-init from https://win.rustup.rs/x86_64

  2. Run rustup-init.exe

  3. Follow the prompts to complete the installation (the default options are recommended)

  4. After installation, close and reopen your terminal to apply the PATH changes

Verify that Rust is installed correctly and check the version:

rustc --version
cargo --version

Note

The Rust installation will be located at %USERPROFILE%\.cargo\bin (typically C:\Users\<username>\.cargo\bin). Do not forget to add the location to the PATH environment variable in Setup environment variables.

8. Install MSYS2

Warning

The Windows’ WSL2 feature conflict with MSYS2. For simplicity, it is highly recommended to disable Windows’ WSL or WSL2 feature entirely.

Additional information can be found on the MSYS2 github.

Download and install the latest MSYS2. Open RV is NOT a mingw64 build. It is a Microscoft Visual Studio 2022 build. Open RV is built with Microsoft Visual Studio 2022 via the CMake “Visual Studio 17 2022” generator.

MSYS2 is only used for convenience as it comes with a package manager with utility packages required for the Open RV build such as cmake, git, flex, bison, nasm, unzip, zip, etc.

8.1 Install required MSYS2 pacman packages

Note

The MSYS2 MingGW64 (mingw64.exe) terminal MUST be used.
Other executables such as MSYS2 (msys2.exe) or MSYS2 MingGW32 (mingw32.exe) will not work.\

MSYS2-MinGW64

From a MSYS2-MinGW64 shell, install the following packages which are required to build Open RV:

pacman -Sy --needed \
        mingw-w64-x86_64-autotools \
        mingw-w64-x86_64-glew \
        mingw-w64-x86_64-libarchive \
        mingw-w64-x86_64-make \
        mingw-w64-x86_64-meson \
        mingw-w64-x86_64-toolchain \
        autoconf  \
        automake \
        bison \
        flex \
        git \
        libtool \
        nasm \
        p7zip \
        patch \
        unzip \
        zip

While installing the MSYS packages, review the list for any missing package. Some packages might not be installed after the first command.

9. Setup environment variables

Note

This is the step where the path of Strawberry Perl, Python, CMake and Qt will be needed.

Some environment variables need to be set within MSYS2 for the Open RV build system. The PATH environment variable must be modified, new environment variables called ACLOCAL_PATH and QT_HOME must be created.

These modifications will be added to the .bash_profile file located in the User’s home directory within the MSYS2 environment. By modifiying .bash_profile, these environment variable will be modified everytime a new MSYS2 MINGW64 terminal is opened.

PATH environment variable

Note

Update the CMake, Strawberry Perl, Python, and Rust locations to reflect your installation paths, using forward slashes (/) for a Unix-style path to prevent issues later on. (e.g., C:\Python310 becomes /c/Python310).

For Rust: Replace <username> with your actual Windows username. You can find your username by running echo %USERNAME% in a Windows command prompt. The Rust installation is located at %USERPROFILE%\.cargo\bin (typically C:\Users\<username>\.cargo\bin), which becomes /c/Users/<username>/.cargo/bin in MSYS2 format.

The following paths must be added to the PATH environment variable within MSYS2:

  • CMake binary directory

  • Python binary directory

  • Rust cargo binary directory

  • MSYS2’s mingw64/bin

  • Strawberry perl directory

The order is important. Do not put Strawberry perl location before MSYS2’s mingw64/bin directory.

echo 'export PATH="/c/Program Files/CMake/bin:/c/Python311:/c/Users/<username>/.cargo/bin:/c/msys64/mingw64/bin:$PATH:/c/Strawberry/perl/bin"' >> ~/.bash_profile

Warning

Remember to replace <username> with your actual Windows username in the commands above.

ACLOCAL_PATH

echo "export ACLOCAL_PATH=/c/msys64/usr/share/aclocal" >> ~/.bash_profile

QT_HOME

Note

Update the Qt location to reflect your installation path, using forward slashes (/) for a Unix-style path (e.g., C:\Qt\5.15.2\msvc2019_64 becomes /c/Qt/5.15.2/msvc2019_64).

echo "export QT_HOME=/c/Qt/6.5.3/msvc2019_64" >> ~/.bash_profile

Apply changes to MSYS2 MINGW64

All the environment variables changes above must be applied. You can do that by closing and re-opening the MSYS2 MINGW64 terminal or by running the following command:

source ~/.bash_profile

10. Build Open RV

Once the platform-specific installation process is complete, building Open RV follows the same process for all platforms. Please refer to the Common Build Instructions for the complete build process.

Windows-Specific Build Notes

Warning

Even as of Windows 11, for legacy reasons, a default system path length is still limited to 254 bytes long. For that reason, it is recommended to clone Open RV into the drive’s root directory (e.g.: C:\).

Warning

Open RV repository should be cloned into the root of a drive (e.g. c:).

Otherwise, the PySide2 compilation could be failing due to the path being too long. If you can’t do that, please take a look at Maximum Path Length Limitation on Microsoft website.