diff --git a/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.cpp b/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.cpp
index c2f79e04d..0d7059e74 100644
--- a/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.cpp
+++ b/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.cpp
@@ -3487,7 +3487,7 @@ string CLuaIHMRyzom::getRegionByAlias(uint32 alias)
 	return ContinentMngr.getRegionNameByAlias(alias);
 }
 
-sint32 CLuaIHMRyzom::getGroundZ(uint32 x, sint32 y)
+float CLuaIHMRyzom::getGroundZ(float x, float y)
 {
 	CVector vect = UserEntity->pos();
 	vect.x = x;
diff --git a/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.h b/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.h
index e27c7ee2e..104fb20e6 100644
--- a/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.h
+++ b/code/ryzom/client/src/interface_v3/lua_ihm_ryzom.h
@@ -214,7 +214,7 @@ private:
 	static sint getCharacterSheetRegionForce(const std::string &sheet);
 	static sint	getCharacterSheetRegionLevel(const std::string &sheet);
 	static std::string getRegionByAlias(uint32 alias);
-	static sint getGroundZ(uint32 x, sint32 y);
+	static float getGroundZ(float x, float y);
 	static int getGroundAtMouse(CLuaState &ls);
 	static int getMousePos(CLuaState &ls);
 	static int getMouseDown(CLuaState &ls);