Add build instructions for LichtFeld Studio

.gitignore

@@ -12,4 +12,4 @@ colmap/share
 colmap/plugins
 colmap/COLMAP.bat
 colmap/RUN_TESTS.bat
-/lichtfeld-studio/LichtFeld-Studio*
+/lichtfeld-studio/LichtFeld-Studio-Portable/

lichtfeld-studio/build-instructions.txt

@@ -0,0 +1,49 @@
+1. Go to AppData directory
+
+```
+cd %APPDATA%
+```
+
+2. Clone and set up vcpkg
+
+```
+git clone https://github.com/microsoft/vcpkg.git
+cd vcpkg && .\bootstrap-vcpkg.bat -disableMetrics && cd ..
+```
+
+3. Run the following in the LichtFeld-Studio directory
+   NOTE: This creates a portable build for devices with CUDA Compute Capability 8.6
+
+```
+cmake -B build -S . -G Ninja ^
+  -DCMAKE_BUILD_TYPE=Release ^
+  -DBUILD_PORTABLE=ON ^
+  -DBUILD_PYTHON_STUBS=OFF ^
+  -DCMAKE_CUDA_ARCHITECTURES=86 ^
+  -DBUILD_CUDA_MIN_SM=86 ^
+  -DCMAKE_TOOLCHAIN_FILE="%APPDATA%\vcpkg\scripts\buildsystems\vcpkg.cmake"
+```
+
+4. Run the following. Adjust the number of threads accordingly
+
+```
+cmake --build build -j4
+```
+
+5. Run the following to create the portable build. 
+
+```
+cmake --install build --prefix ../LichtFeld-Studio-Portable
+```
+
+| NOTE: The full directory structure of the portable install should look like so:
+
+```
+.
+├── bin/
+├── DLLs/
+├── extensions/
+├── Lib/
+├── share/
+└── LICENSE (35 KB)
+```