Build on Windows¶

Building OrcaSlicer for 64-bit Windows. MSVC is the default toolchain, and clang-cl (LLVM) is supported as an alternative.

Tools Required
Hardware Requirements
Get the Source
Build the Dependencies
Building with MSVC
Building with clang-cl
Troubleshooting

Tools Required¶

Visual Studio 2026, 2022 or 2019, with the Desktop development with C++ workload

winget install --id=Microsoft.VisualStudio.Community -e --override "--add Microsoft.VisualStudio.Workload.NativeDesktop --includeRecommended --passive --wait"

CMake
```
winget install --id=Kitware.CMake -e
```

Strawberry Perl

winget install --id=StrawberryPerl.StrawberryPerl -e

Git
```
winget install --id=Git.Git -e
```

Important

A plain winget install of Visual Studio installs the IDE without any C++ compiler, and the build fails later with CMake unable to find a Visual Studio instance. The --override flags above add the required Desktop development with C++ workload.

If Visual Studio is already installed without it, add the workload from Visual Studio Installer -> Modify -> check Desktop development with C++ -> Modify.

Important

Strawberry Perl bundles its own CMake. If it comes first on PATH, cmake --version reports that copy rather than the one you installed. Run where cmake to list the active copies, then reorder System Environment Variables > Path so the real one wins:

C:\Program Files\CMake\bin
C:\Strawberry\c\bin

OrcaSlicer needs CMake 3.13 or newer, and 3.21 or newer for the clang-cl presets below. CMake 4.x is fine.

windows_variables_path

windows_variables_order

Tip

GitHub Desktop is optional and gives you a GUI for repository and branch management:

winget install --id=GitHub.GitHubDesktop -e

Hardware Requirements¶

Minimum 16 GB RAM
Minimum 23 GB free disk space
64-bit CPU
64-bit Windows 10 or later

Get the Source¶

Clone the repository, either from GitHub Desktop or on the command line:

git clone https://github.com/OrcaSlicer/OrcaSlicer

Everything below runs from the x64 Native Tools Command Prompt for VS, in the clone:

cd path\to\OrcaSlicer

Build the Dependencies¶

build_release_vs.bat builds the dependencies with MSVC. clang-cl links against those same ones, because it targets the MSVC ABI. Build them once:

build_release_vs.bat deps

They install into deps\build\OrcaSlicer_dep\usr\local.

Debug builds link the debug C runtime (/MDd), which cannot be mixed with the release one, so they need a separate set:

build_release_vs.bat deps debug

Those install into deps\build-dbg\ and are required for a Debug build under either toolchain.

Building with MSVC¶

build_release_vs.bat generates a Visual Studio solution and builds it with MSVC. This is the toolchain CI uses.

Build OrcaSlicer:
```
build_release_vs.bat slicer
```
Open the generated solution:
```
build\OrcaSlicer.slnx
```
Set the build configuration to Release and run the Local Windows Debugger.
The executable is written to:
```
build\src\Release\orca-slicer.exe
```

For a Debug build, build the debug dependencies first, then:

build_release_vs.bat slicer debug

That writes build-dbg\OrcaSlicer.slnx and build-dbg\src\Debug\orca-slicer.exe, and finds deps\build-dbg on its own because the build directory is named to match.

build_release_vs.bat slicer tests builds the test suites as well. See How to Test for running them.

Note

The first build of any branch is slow. After that, changes to .cpp files compile quickly and changes to .hpp files take longer depending on how widely the header is included. Switching branches back and forth also forces a long rebuild even when nothing else changed.

Building with clang-cl¶

OrcaSlicer also builds with the clang-cl (LLVM) toolchain and the Ninja generator. It compiles the project considerably faster than MSVC on the same machine, which is the main reason to use it. Official builds and CI use MSVC, so a change still has to compile there.

Important

clang-cl support was added in OrcaSlicer PR #14375 (merged 2026-08-19). A checkout that predates it will not compile with clang-cl. Rebase onto main first.

Additional Tools¶

On top of the Desktop development with C++ workload:

The C++ Clang Compiler for Windows individual component (Microsoft.VisualStudio.Component.VC.Llvm.Clang). Add it from Visual Studio Installer -> Modify -> Individual components, searching for Clang. It installs clang-cl.exe and lld-link.exe under VC\Tools\Llvm\x64\bin.
Ninja, for the command-line build only. Visual Studio and VS Code each ship their own copy.
```
winget install --id=Ninja-build.Ninja -e
```

Note

The separate MSBuild support for LLVM (clang-cl) toolset component (Microsoft.VisualStudio.Component.VC.Llvm.ClangToolset) is only needed to drive clang-cl through the Visual Studio generator with -T ClangCL. The Ninja setup below does not use it.

The Preset File¶

Visual Studio, VS Code and the command line all read the same CMake preset file. Create CMakeUserPresets.json in the repository root:

{
  "version": 3,
  "configurePresets": [
    {
      "name": "x64-clang",
      "displayName": "x64 Clang",
      "description": "clang-cl and Ninja Multi-Config, built against deps/build",
      "generator": "Ninja Multi-Config",
      "binaryDir": "${sourceDir}/out/build/${presetName}",
      "architecture": { "value": "x64", "strategy": "external" },
      "toolset": { "value": "host=x64", "strategy": "external" },
      "environment": {
        "CC": "clang-cl",
        "CXX": "clang-cl"
      },
      "cacheVariables": {
        "CMAKE_CONFIGURATION_TYPES": "Release;RelWithDebInfo;MinSizeRel",
        "CMAKE_PREFIX_PATH": "${sourceDir}/deps/build/OrcaSlicer_dep/usr/local",
        "BUILD_TESTS": { "type": "BOOL", "value": "ON" }
      },
      "vendor": {
        "microsoft.com/VisualStudioSettings/CMake/1.0": {
          "hostOS": [ "Windows" ],
          "intelliSenseMode": "windows-clang-x64"
        }
      }
    },
    {
      "name": "x64-clang-debug",
      "displayName": "x64 Clang Debug",
      "description": "clang-cl and Ninja, built against deps/build-dbg",
      "generator": "Ninja",
      "binaryDir": "${sourceDir}/out/build/${presetName}",
      "architecture": { "value": "x64", "strategy": "external" },
      "toolset": { "value": "host=x64", "strategy": "external" },
      "environment": {
        "CC": "clang-cl",
        "CXX": "clang-cl"
      },
      "cacheVariables": {
        "CMAKE_BUILD_TYPE": "Debug",
        "CMAKE_PREFIX_PATH": "${sourceDir}/deps/build-dbg/OrcaSlicer_dep/usr/local",
        "BUILD_TESTS": { "type": "BOOL", "value": "ON" }
      },
      "vendor": {
        "microsoft.com/VisualStudioSettings/CMake/1.0": {
          "hostOS": [ "Windows" ],
          "intelliSenseMode": "windows-clang-x64"
        }
      }
    }
  ],
  "buildPresets": [
    { "name": "x64-clang-release",        "configurePreset": "x64-clang", "configuration": "Release" },
    { "name": "x64-clang-relwithdebinfo", "configurePreset": "x64-clang", "configuration": "RelWithDebInfo" },
    { "name": "x64-clang-minsizerel",     "configurePreset": "x64-clang", "configuration": "MinSizeRel" },
    { "name": "x64-clang-debug-build",    "configurePreset": "x64-clang-debug" }
  ],
  "testPresets": [
    {
      "name": "x64-clang-test-release",
      "configurePreset": "x64-clang",
      "configuration": "Release",
      "output": { "outputOnFailure": true }
    },
    {
      "name": "x64-clang-test-relwithdebinfo",
      "configurePreset": "x64-clang",
      "configuration": "RelWithDebInfo",
      "output": { "outputOnFailure": true }
    },
    {
      "name": "x64-clang-test-debug",
      "configurePreset": "x64-clang-debug",
      "output": { "outputOnFailure": true }
    }
  ]
}

x64-clang uses Ninja Multi-Config, so one build directory holds Release, RelWithDebInfo and MinSizeRel. Switching between them needs no reconfigure. x64-clang-debug is separate because it builds against the Debug dependencies.

Only RelWithDebInfo is compiled with /Zi, so switch to it when you need to debug. Release and MinSizeRel produce no symbols to step through.

Important

Do not omit CMAKE_PREFIX_PATH. Without it, CMake derives the dependency location from the name of the build directory, so out/build/x64-clang sends it looking in deps\x64-clang\ and configuration fails at find_package(Boost 1.83.0 REQUIRED) with Could not find a package configuration file provided by "Boost". Only a build directory named exactly build resolves on its own, and that name is already taken by the MSVC build.

Tip

BUILD_TESTS is ON so the test suites build alongside the application, and the test presets can run them. Set it to OFF for slightly faster builds if you do not need them. See How to Test.

Note

CMakeUserPresets.json holds personal settings and is not covered by the repository's .gitignore, so it shows up as untracked. Leave it out of commits.

Visual Studio¶

Open the repository as a CMake project: File > Open > Folder. Do not open build\OrcaSlicer.slnx, which is the MSVC solution.
Pick a build preset in the Configuration dropdown, x64-clang-release for instance. Visual Studio labels that dropdown Configuration, but its entries are build presets, and each one names a configure preset and a configuration together, so it is the only thing to set.
Set the startup item to the orca-slicer.exe entry whose path matches that preset, src\Release\orca-slicer.exe for x64-clang-release. Visual Studio defaults to a different executable and remembers your choice from then on. Do not pick either (Install) entry.
Build with Build > Build All. The executable is written under out\build\<configure preset>\, so x64-clang-release gives:
```
out\build\x64-clang\src\Release\orca-slicer.exe
```
Run the tests with Test > Run CTests for OrcaSlicer once they are built.

Note

x64-clang-debug-build uses a single-configuration generator, so it has no per-configuration subdirectory. Its startup item is src\orca-slicer.exe and the executable lands in out\build\x64-clang-debug\src\orca-slicer.exe.

Note

Visual Studio may show a Build failed prompt on the first build even though the build succeeded and the application runs. Choosing to continue starts it normally, and later builds do not prompt. Check the Output pane instead of the dialog. A real failure names a file, and a failed configure step produces the same dialog.

VS Code¶

Requires the CMake Tools extension (ms-vscode.cmake-tools). It switches to preset mode on its own once CMakeUserPresets.json exists, so there is nothing to configure.

Open the CMake panel from the Activity Bar and set the entries under Project Status:

Configure to x64 Clang
Build to the configuration you want, x64-clang-release for instance
Test to x64-clang-test-release
Launch and Debug to OrcaSlicer_app_gui, both of which default to all. Pick the entry under src\Release\, not OrcaSlicer_app_gui (Install)

The build preset carries the configuration, so switching between Release, RelWithDebInfo and MinSizeRel means switching build preset. The same entries are on the Command Palette under CMake: Select Configure Preset and CMake: Select Build Preset.

The Launch and Debug entries in that panel run the selected target directly. To debug with F5 instead, add a launch configuration to .vscode/launch.json:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "OrcaSlicer",
      "type": "cppvsdbg",
      "request": "launch",
      "program": "${command:cmake.launchTargetPath}",
      "args": [],
      "cwd": "${command:cmake.launchTargetDirectory}",
      "stopAtEntry": false,
      "console": "internalConsole"
    }
  ]
}

cppvsdbg is the Windows debugger and reads the PDBs clang-cl produces. The ${command:cmake...} values follow the active launch target and build preset, so nothing is hard-coded. cwd starts the application next to the resources junction it needs.

Important

Without that configuration, Run > Start Debugging offers to generate one and suggests C++ (GDB/LLDB), which targets MinGW and LLDB. The template it writes debugs a single source file and fails with Variable ${fileDirname} can not be resolved.

Command Line¶

The x64 Native Tools Command Prompt for VS puts clang-cl, lld-link and the Windows SDK on PATH. From the repository root:

cmake --preset x64-clang
cmake --build --preset x64-clang-release
ctest --preset x64-clang-test-release

The executable is written to:

out\build\x64-clang\src\Release\orca-slicer.exe

Troubleshooting¶

Dependencies¶

Tip

Some changes are not picked up by a rebuild because they live in the prebuilt dependencies, not in the OrcaSlicer sources. Rebuild the affected dependency target instead of everything under deps/.

For example, after modifying wxInspector, run this from the repository root:

cmake --build deps\build --target dep_wxInspector --config Release

The path is relative, so from anywhere else CMake fails with ... deps\build is not a directory. Visual Studio's built-in terminal (View > Terminal) starts in the solution folder build\, so use ..\deps\build there. Then rebuild so the updated dependency is linked in.

Tip

If a dependency build fails with patch does not apply, delete deps\build (and deps\build-dbg) and build them again. git apply cannot re-apply a patch to sources that already carry it.

Tip

If the build fails outright, delete the build/ and deps/build/ directories to clear cached build data and start again.

Tip

If the build fails while configuring ZLIB, uninstall ZLIB from your Vcpkg library.

Windows SDK¶

Tip

If the Fix model option is missing from an object's context menu, the build did not pick up the Windows SDK. To fix it:

Locate the winrt folder in your Windows SDK installation, for example:

C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\winrt

The exact path varies with your Windows SDK version.

Open the libslic3r_gui project properties and go to Configuration Properties > C/C++ > Preprocessor > Preprocessor Definitions. Add HAS_WIN10SDK.
Open the OrcaSlicer_app_gui project properties and go to Configuration Properties > C/C++ > General > Additional Include Directories. Add the path to the winrt folder from step 1.
Build the solution.

clang-cl¶

PR #14375 changed how two dependencies are built. Dependencies built before it fail under clang-cl:

TBB was compiled with /GL, and lld-link rejects LTCG objects. This surfaces late, at the Linking CXX shared library src\OrcaSlicer.dll step, as one error per object with no file or line:
```
lld-link: error: tbb.dir\Release\queuing_rw_mutex.obj: is not a native COFF file. Recompile without /GL?
```
wxWidgets installs its libraries under vc_x64_lib, but its own CMake config file looks for a clang_x64_lib directory when the compiler is clang-cl. This fails at configure time, with an include could not find requested file error naming clang_x64_lib/wxWidgetsTargets.cmake.

Rebuilding the dependencies fixes both:

build_release_vs.bat deps

To rebuild only TBB, delete deps\build\dep_TBB-prefix first and run the same command.