.gitmodules

@@ -11,3 +11,6 @@
 [submodule "cpp/vendor/glfw"]
 	path = cpp/vendor/glfw
 	url = https://github.com/glfw/glfw.git
+[submodule "cpp/vendor/implot3d"]
+	path = cpp/vendor/implot3d
+	url = https://github.com/brenocq/implot3d.git

cpp/CMakeLists.txt

@@ -33,6 +33,18 @@ add_library(implot STATIC
 target_include_directories(implot PUBLIC ${IMPLOT_DIR})
 target_link_libraries(implot PUBLIC imgui)
 
+# --- Vendor: ImPlot3D ---
+# Pinned to v0.4 (commit 41ae3e447c0de20ecab95d38a4b4dc0835a3efc2).
+# See cpp/vendor/implot3d.VENDORING.md for update procedure.
+set(IMPLOT3D_DIR ${CMAKE_CURRENT_SOURCE_DIR}/vendor/implot3d)
+add_library(implot3d STATIC
+    ${IMPLOT3D_DIR}/implot3d.cpp
+    ${IMPLOT3D_DIR}/implot3d_items.cpp
+    ${IMPLOT3D_DIR}/implot3d_meshes.cpp
+)
+target_include_directories(implot3d PUBLIC ${IMPLOT3D_DIR})
+target_link_libraries(implot3d PUBLIC imgui)
+
 # --- Vendor: Tracy (optional) ---
 if(TRACY_ENABLE)
     set(TRACY_DIR ${CMAKE_CURRENT_SOURCE_DIR}/vendor/tracy)
@@ -102,7 +114,7 @@ target_include_directories(fn_framework PUBLIC
 target_compile_definitions(fn_framework PUBLIC
     FN_CPP_ROOT="${CMAKE_CURRENT_SOURCE_DIR}"
 )
-target_link_libraries(fn_framework PUBLIC imgui implot)
+target_link_libraries(fn_framework PUBLIC imgui implot implot3d)
 if(TRACY_ENABLE)
     target_link_libraries(fn_framework PUBLIC tracy)
 endif()

cpp/vendor/implot3d.VENDORING.md

@@ -0,0 +1,41 @@
+# ImPlot3D — vendoring notes
+
+3D plotting library for Dear ImGui by Breno Cunha Queiroz, sister project to
+[ImPlot](https://github.com/epezent/implot).
+
+- **Upstream:** https://github.com/brenocq/implot3d
+- **License:** MIT (see `cpp/vendor/implot3d/LICENSE`)
+- **Version:** v0.4
+- **Pinned commit:** `41ae3e447c0de20ecab95d38a4b4dc0835a3efc2`
+  (2026-04-05, _"chore: bump version to v0.4"_)
+
+The vendor lives as a git submodule in `cpp/vendor/implot3d` and is checked
+out at the pinned commit above.
+
+## Files compiled into the `implot3d` CMake target
+
+- `implot3d.cpp`
+- `implot3d_items.cpp`
+- `implot3d_meshes.cpp`
+
+`implot3d_demo.cpp` and the contents of `example/` are intentionally left
+out of the build — kept for reference only.
+
+## Update procedure
+
+```bash
+cd cpp/vendor/implot3d
+git fetch origin
+git checkout <new-commit>
+cd ../../..
+git add cpp/vendor/implot3d
+# Update the pinned commit in this file.
+git commit -m "chore(vendor): bump implot3d to <new-commit>"
+```
+
+## Used by
+
+- `cpp/functions/viz/surface_plot_3d.cpp` — `ImPlot3D::PlotSurface`
+- `cpp/functions/viz/scatter_3d.cpp` — `ImPlot3D::PlotScatter`
+- `cpp/framework/app_base.cpp` — creates/destroys the ImPlot3D context
+  alongside the ImPlot one.