diff --git a/src/libslic3r/GCode/SeamPlacer.hpp b/src/libslic3r/GCode/SeamPlacer.hpp
--- a/src/libslic3r/GCode/SeamPlacer.hpp
+++ b/src/libslic3r/GCode/SeamPlacer.hpp
@@ -17,6 +17,7 @@
 #include "libslic3r/BoundingBox.hpp"
 #include "libslic3r/AABBTreeIndirect.hpp"
 #include "libslic3r/KDTreeIndirect.hpp"
+#include "libslic3r/TriangleMesh.hpp"