diff --git a/nel/tools/build_gamedata/processes/ai_wmap/2_build.py b/nel/tools/build_gamedata/processes/ai_wmap/2_build.py
index 8aa63f62f..8dd43be16 100755
--- a/nel/tools/build_gamedata/processes/ai_wmap/2_build.py
+++ b/nel/tools/build_gamedata/processes/ai_wmap/2_build.py
@@ -68,13 +68,15 @@ else:
 		printLog(log, ">>> Generate sized wmap <<<")
 		subprocess.call([ AiBuildWmap, "pacsBuildGabarit " + AiWmapContinentName ])
 		printLog(log, ">>> Generate cwmaps for each size <<<")
-		subprocess.call([ AiBuildWmap, "pacsBuildWmap " + AiWmapContinentName + "_0" ])
-		subprocess.call([ AiBuildWmap, "pacsBuildWmap " + AiWmapContinentName + "_1" ])
-		subprocess.call([ AiBuildWmap, "pacsBuildWmap " + AiWmapContinentName + "_2" ])
+		callParallelProcess([ AiBuildWmap, "pacsBuildWmap " + AiWmapContinentName + "_0" ])
+		callParallelProcess([ AiBuildWmap, "pacsBuildWmap " + AiWmapContinentName + "_1" ])
+		callParallelProcess([ AiBuildWmap, "pacsBuildWmap " + AiWmapContinentName + "_2" ])
+		flushParallelProcesses()
 		printLog(log, ">>> Generate bitmap for each size <<<")
-		subprocess.call([ AiBuildWmap, "pacsBuildBitmap " + AiWmapContinentName + "_0" ])
-		subprocess.call([ AiBuildWmap, "pacsBuildBitmap " + AiWmapContinentName + "_1" ])
-		subprocess.call([ AiBuildWmap, "pacsBuildBitmap " + AiWmapContinentName + "_2" ])
+		callParallelProcess([ AiBuildWmap, "pacsBuildBitmap " + AiWmapContinentName + "_0" ])
+		callParallelProcess([ AiBuildWmap, "pacsBuildBitmap " + AiWmapContinentName + "_1" ])
+		callParallelProcess([ AiBuildWmap, "pacsBuildBitmap " + AiWmapContinentName + "_2" ])
+		flushParallelProcesses()
 		printLog(log, ">>> Clear height maps for size 1 and 2 <<<")
 		subprocess.call([ AiBuildWmap, "pacsClearHeightmap " + AiWmapContinentName ])
 		printLog(log, ">>> Cut tga for world editor <<<")