diff --git a/src/3d/poly2tri/common/shapes.cc b/external/poly2tri/common/shapes.cc
similarity index 100%
rename from src/3d/poly2tri/common/shapes.cc
rename to external/poly2tri/common/shapes.cc
diff --git a/src/3d/poly2tri/common/shapes.h b/external/poly2tri/common/shapes.h
similarity index 100%
rename from src/3d/poly2tri/common/shapes.h
rename to external/poly2tri/common/shapes.h
diff --git a/src/3d/poly2tri/common/utils.h b/external/poly2tri/common/utils.h
similarity index 100%
rename from src/3d/poly2tri/common/utils.h
rename to external/poly2tri/common/utils.h
diff --git a/src/3d/poly2tri/poly2tri.h b/external/poly2tri/poly2tri.h
similarity index 100%
rename from src/3d/poly2tri/poly2tri.h
rename to external/poly2tri/poly2tri.h
diff --git a/src/3d/poly2tri/sweep/advancing_front.cc b/external/poly2tri/sweep/advancing_front.cc
similarity index 100%
rename from src/3d/poly2tri/sweep/advancing_front.cc
rename to external/poly2tri/sweep/advancing_front.cc
diff --git a/src/3d/poly2tri/sweep/advancing_front.h b/external/poly2tri/sweep/advancing_front.h
similarity index 100%
rename from src/3d/poly2tri/sweep/advancing_front.h
rename to external/poly2tri/sweep/advancing_front.h
diff --git a/src/3d/poly2tri/sweep/cdt.cc b/external/poly2tri/sweep/cdt.cc
similarity index 100%
rename from src/3d/poly2tri/sweep/cdt.cc
rename to external/poly2tri/sweep/cdt.cc
diff --git a/src/3d/poly2tri/sweep/cdt.h b/external/poly2tri/sweep/cdt.h
similarity index 100%
rename from src/3d/poly2tri/sweep/cdt.h
rename to external/poly2tri/sweep/cdt.h
diff --git a/src/3d/poly2tri/sweep/sweep.cc b/external/poly2tri/sweep/sweep.cc
similarity index 100%
rename from src/3d/poly2tri/sweep/sweep.cc
rename to external/poly2tri/sweep/sweep.cc
diff --git a/src/3d/poly2tri/sweep/sweep.h b/external/poly2tri/sweep/sweep.h
similarity index 100%
rename from src/3d/poly2tri/sweep/sweep.h
rename to external/poly2tri/sweep/sweep.h
diff --git a/src/3d/poly2tri/sweep/sweep_context.cc b/external/poly2tri/sweep/sweep_context.cc
similarity index 100%
rename from src/3d/poly2tri/sweep/sweep_context.cc
rename to external/poly2tri/sweep/sweep_context.cc
diff --git a/src/3d/poly2tri/sweep/sweep_context.h b/external/poly2tri/sweep/sweep_context.h
similarity index 100%
rename from src/3d/poly2tri/sweep/sweep_context.h
rename to external/poly2tri/sweep/sweep_context.h
diff --git a/src/3d/CMakeLists.txt b/src/3d/CMakeLists.txt
index 5ac1362304d..17efe3faf90 100644
--- a/src/3d/CMakeLists.txt
+++ b/src/3d/CMakeLists.txt
@@ -43,11 +43,11 @@ SET(QGIS_3D_SRCS
   #terrain/quantizedmeshgeometry.cpp
   #terrain/quantizedmeshterraingenerator.cpp
 
-  poly2tri/common/shapes.cc
-  poly2tri/sweep/advancing_front.cc
-  poly2tri/sweep/cdt.cc
-  poly2tri/sweep/sweep_context.cc
-  poly2tri/sweep/sweep.cc
+  ${CMAKE_SOURCE_DIR}/external/poly2tri/common/shapes.cc
+  ${CMAKE_SOURCE_DIR}/external/poly2tri/sweep/advancing_front.cc
+  ${CMAKE_SOURCE_DIR}/external/poly2tri/sweep/cdt.cc
+  ${CMAKE_SOURCE_DIR}/external/poly2tri/sweep/sweep_context.cc
+  ${CMAKE_SOURCE_DIR}/external/poly2tri/sweep/sweep.cc
 )
 
 SET(QGIS_3D_MOC_HDRS