diff --git a/code/ryzom/server/src/ai_service/ai_bot_fauna.cpp b/code/ryzom/server/src/ai_service/ai_bot_fauna.cpp
index 84bc47bf1..a6573d4bb 100644
--- a/code/ryzom/server/src/ai_service/ai_bot_fauna.cpp
+++ b/code/ryzom/server/src/ai_service/ai_bot_fauna.cpp
@@ -501,7 +501,7 @@ void CSpawnBotFauna::getBestTarget()
 								if (	canMove()
 									&&	!player->isAggressive()
 									&&	entity->wpos().isValid()
-									&&	(entity->wpos().getFlags()&entity->getAStarFlag())==0)
+									&&	isPlaceAllowed(entity->getAStarFlag(), entity->wpos().getFlags()))
 								{
 									// Suppose we can go to him
 									bool canChange = true;
@@ -706,7 +706,7 @@ void CSpawnBotFauna::getBestTarget()
 										if (	profile
 											&&	profile->getAIProfileType()==ACTIVITY_CORPSE
 											&&	botCreat->wpos().isValid()
-											&&	!(botCreat->wpos().getFlags()&botCreat->getAStarFlag())
+											&&	isPlaceAllowed(botCreat->getAStarFlag(), botCreat->wpos().getFlags())
 											)
 										{
 											CCorpseFaunaProfile	*corpseProfile=NLMISC::safe_cast<CCorpseFaunaProfile*>(profile);
@@ -951,7 +951,7 @@ void CMovementMagnet::getNewDestination(RYAI_MAP_CRUNCH::CWorldPosition const& a
 				continue;
 
 			if	(	!faunaBot->wpos().isValid()
-				||	(faunaBot->wpos().getFlags()&denyFlag)!=0)
+				||	!isPlaceAllowed(denyFlag, faunaBot->wpos().getFlags()))
 				continue;
 
 			// can be optimize by in avoid inversion.
@@ -990,7 +990,7 @@ void CMovementMagnet::getNewDestination(RYAI_MAP_CRUNCH::CWorldPosition const& a
 		
 		//	check if its a nogo and water proof position.
 		if (	!wRndPos.isValid()
-			||	(wRndPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlag)!=0	)
+			||	!isPlaceAllowed(denyFlag, wRndPos.getTopologyRef().getCstTopologyNode().getFlags()))
 			continue;
 		
 	#if !FINAL_VERSION
@@ -1126,7 +1126,7 @@ CReturnMovementMagnet::CReturnMovementMagnet(RYAI_MAP_CRUNCH::CWorldPosition con
 
 void CReturnMovementMagnet::getNewDestination(RYAI_MAP_CRUNCH::CWorldPosition const& alternativePos, RYAI_MAP_CRUNCH::TAStarFlag denyFlag)
 {
-	if (_ForcedDest.isValid() && (_ForcedDest.getTopologyRef().getCstTopologyNode().getFlags()&denyFlag)==0)
+	if (_ForcedDest.isValid() && isPlaceAllowed(denyFlag, _ForcedDest.getTopologyRef().getCstTopologyNode().getFlags()))
 		_PathCont.setDestination(_ForcedDest);
 	else
 		CMovementMagnet::getNewDestination(alternativePos, denyFlag);
diff --git a/code/ryzom/server/src/ai_service/ai_generic_fight.cpp b/code/ryzom/server/src/ai_service/ai_generic_fight.cpp
index fb8235063..cec456267 100644
--- a/code/ryzom/server/src/ai_service/ai_generic_fight.cpp
+++ b/code/ryzom/server/src/ai_service/ai_generic_fight.cpp
@@ -309,7 +309,7 @@ void CBotProfileFlee::updateProfile(uint ticksSinceLastUpdate)
 			{
 				RYAI_MAP_CRUNCH::CWorldPosition wpos=rootCell->getWorldPosition(_Bot->getPersistent().getChildIndex()&3);
 				if	(	wpos.isValid()
-					&&	(wpos.getFlags()&_DenyFlags)==0 )	// verify that we got some compatible flags ..
+					&&	isPlaceAllowed(_DenyFlags, wpos.getFlags()))	// verify that we got some compatible flags ..
 				{
 					_LastDir=startDir;
 					_LastStartPos=_Bot->wpos();
diff --git a/code/ryzom/server/src/ai_service/ai_generic_fight_helpers.cpp b/code/ryzom/server/src/ai_service/ai_generic_fight_helpers.cpp
index 4b655422c..f6d0af29d 100644
--- a/code/ryzom/server/src/ai_service/ai_generic_fight_helpers.cpp
+++ b/code/ryzom/server/src/ai_service/ai_generic_fight_helpers.cpp
@@ -374,7 +374,7 @@ bool s_move(
 					0.5f);
 			// If we can't follow the path or the computed pos is invalid
 			if (	status==CFollowPath::FOLLOW_NO_PATH
-				||	(_Bot->wpos().isValid() && (_Bot->wpos().getFlags()&_Bot->getAStarFlag())!=0))
+				||	(_Bot->wpos().isValid() && !isPlaceAllowed(_Bot->getAStarFlag(), _Bot->wpos().getFlags())))
 			{
 				// Restore position
 				_Bot->setPos(lastPos);
@@ -605,7 +605,7 @@ static void s_updateProfile(
 	_AtAttackDist = norm < _RangeMax;
 	
 	// Check if target can be attacked
-	bool const targetInForbiddenZone = ((!target->wpos().isValid())||(target->wpos().getFlags()&_Bot->getAStarFlag())!=0);
+	bool const targetInForbiddenZone = ((!target->wpos().isValid())||!isPlaceAllowed(_Bot->getAStarFlag(), target->wpos().getFlags()));
 	
 /****************************************************************************/
 /* Profile main processing                                                  */
diff --git a/code/ryzom/server/src/ai_service/ai_grp_fauna.cpp b/code/ryzom/server/src/ai_service/ai_grp_fauna.cpp
index 5738af614..daa9de3c6 100644
--- a/code/ryzom/server/src/ai_service/ai_grp_fauna.cpp
+++ b/code/ryzom/server/src/ai_service/ai_grp_fauna.cpp
@@ -836,7 +836,7 @@ bool CGrpFauna::spawnPop(uint popVersion)
 		if (!places()[i]->worldValidPos().isValid())
 			return	false;
 		const	RYAI_MAP_CRUNCH::TAStarFlag	flags=places()[i]->worldValidPos().getTopologyRef().getCstTopologyNode().getFlags();
-		if	((flags&getAStarFlag())!=0)
+		if(!isPlaceAllowed(getAStarFlag(), flags)) // if place is not allowed - we now deal with creatures that can't go on the ground
 			return	false;
 	}
 
diff --git a/code/ryzom/server/src/ai_service/ai_mgr_fauna.cpp b/code/ryzom/server/src/ai_service/ai_mgr_fauna.cpp
index b178cccff..68312d6ca 100644
--- a/code/ryzom/server/src/ai_service/ai_mgr_fauna.cpp
+++ b/code/ryzom/server/src/ai_service/ai_mgr_fauna.cpp
@@ -97,12 +97,37 @@ IAliasCont* CMgrFauna::getAliasCont(TAIType type)
 
 CAliasTreeOwner* CMgrFauna::createChild(IAliasCont* cont, CAIAliasDescriptionNode* aliasTree)
 {
+	RYAI_MAP_CRUNCH::TAStarFlag flags = RYAI_MAP_CRUNCH::Nothing;
+	// this hack is to retrieve the AStar flags from the fauna group. We expect the groupname to be as follows : groupname:AStarFlag[|AStarFlag]
+	std::string key, tail;
+	std::string p = NLMISC::toLower(this->getAliasFullName()); // force lowercase
+	
+	AI_SHARE::stringToKeywordAndTail(p, key, tail);
+	int bAstarFlags = 0;
+	if (!tail.empty()){ //AStarFlags were provided
+		bAstarFlags = 1;
+		vector<string> sFlags;
+		NLMISC::splitString(tail, "|", sFlags);
+		FOREACHC(it, vector<string>, sFlags){
+			TAStarFlag tmpflag = RYAI_MAP_CRUNCH::toAStarFlag(*it);
+			if(	(tmpflag == TAStarFlag::Nothing) &&
+				it->compare("nothing")){ // this is not a valid AStarFlags => Let's preserve the default way the fauna is handled
+				bAstarFlags = 0;
+				break;
+			}
+			flags = RYAI_MAP_CRUNCH::TAStarFlag( flags | tmpflag);
+		}
+	}
+	
+	if(!bAstarFlags){
+		flags = WaterAndNogo;
+	}
 	CAliasTreeOwner* child = NULL;
 	
 	switch (aliasTree->getType())
 	{
 	case AITypeGrp:
-		child = new CGrpFauna(this, aliasTree, WaterAndNogo);
+		child = new CGrpFauna(this, aliasTree, flags);
 		break;
 	case AITypeEvent:
 		child = new CAIEventReaction(getStateMachine(), aliasTree);
diff --git a/code/ryzom/server/src/ai_service/continent.cpp b/code/ryzom/server/src/ai_service/continent.cpp
index 4745a19e4..96c172c72 100644
--- a/code/ryzom/server/src/ai_service/continent.cpp
+++ b/code/ryzom/server/src/ai_service/continent.cpp
@@ -1530,7 +1530,10 @@ bool CCellZone::findRestAndFoodFaunaZoneInCellList(CFaunaZone const*& rest, CPro
 	CPropertySet activities[CCellChoice::MAX_ZONE_SCORE];
 	activities[CCellChoice::FOOD_ZONE_SCORE].merge(foodActivity);
 	activities[CCellChoice::REST_ZONE_SCORE].merge(restActivity);
-	
+
+	CPossibleTAStarFlags PossibleTAStarFlags;  // possible TAStarFlags
+	const int nFlags = PossibleTAStarFlags.buildTAStarFlagsList(denyflags); // we build the list according to the deny flags
+
 	// Look for a conveninent zone in a convenient cell.
 	if (extensiveDebug) nldebug("ED0001.02: cells.size()=%d", cells.size());
 	// For each cell
@@ -1586,22 +1589,15 @@ bool CCellZone::findRestAndFoodFaunaZoneInCellList(CFaunaZone const*& rest, CPro
 					continue;
 				}
 				
-				TAStarFlag const flags = (TAStarFlag)(wpos.getFlags()&GroundFlags);	//	Erase unused flags.
+
 				float const score = faunaZone->getFreeAreaScore();
 				
-				for	(TAStarFlag	possibleFlag=Nothing;possibleFlag<=GroundFlags;possibleFlag=(TAStarFlag)(possibleFlag+2))	//	tricky !! -> to replace with a defined list of flags to checks.
-				{
-					const	uint32	incompatibilityFlags=possibleFlag&denyflags&GroundFlags;	//	Erase unused flags.
-					if	(incompatibilityFlags)
-					{
-						if (extensiveDebug) nldebug("ED0001.06: incompatibilityFlags");
-						continue;
-					}
-					
+				for(int i = 0;i < nFlags;i++){
+					TAStarFlag	possibleFlag = PossibleTAStarFlags.get(i);
 					const	uint32	masterTopo=wpos.getTopologyRef().getCstTopologyNode().getMasterTopo(possibleFlag);
-					if	(masterTopo==~0)
+					if(masterTopo==CTopology::TTopologyId::UNDEFINED_TOPOLOGY)
 					{
-						if (extensiveDebug) nldebug("ED0001.07: masterTopo==~0");
+						if (extensiveDebug) nldebug("ED0001.07: CTopology::TTopologyId::UNDEFINED_TOPOLOGY");
 						continue;
 					}
 					
@@ -1611,7 +1607,7 @@ bool CCellZone::findRestAndFoodFaunaZoneInCellList(CFaunaZone const*& rest, CPro
 						continue;
 					}
 					
-					CCellChoice::CZoneScore	&zoneScore=searchMap[possibleFlag][masterTopo].zones[typeZone];
+					CCellChoice::CZoneScore	&zoneScore=searchMap[possibleFlag & WaterAndNogo][masterTopo].zones[typeZone];
 					
 					if	(score<zoneScore.score)
 					{
@@ -1662,8 +1658,8 @@ bool CCellZone::findRestAndFoodFaunaZoneInCellList(CFaunaZone const*& rest, CPro
 #if !FINAL_VERSION
 			const	RYAI_MAP_CRUNCH::TAStarFlag	restFlags=rest->worldValidPos().getTopologyRef().getCstTopologyNode().getFlags();
 			const	RYAI_MAP_CRUNCH::TAStarFlag	foodFlags=food->worldValidPos().getTopologyRef().getCstTopologyNode().getFlags();
-			nlassert((restFlags&denyflags)==0);
-			nlassert((foodFlags&denyflags)==0);
+			nlassert(isPlaceAllowed(denyflags, restFlags));
+			nlassert(isPlaceAllowed(denyflags, foodFlags));
 #endif
 			return	true;
 		}
@@ -1740,7 +1736,7 @@ const	CFaunaZone	*CCellZone::lookupFaunaZone(const	CPropertySet &activity,	TASta
 			}
 
 			const	RYAI_MAP_CRUNCH::TAStarFlag	flags=faunaZone->worldValidPos().getTopologyRef().getCstTopologyNode().getFlags();
-			if	(flags&denyflags)
+			if	(!isPlaceAllowed(denyflags, flags))
 				continue;
 
 			const	float	score=faunaZone->getFreeAreaScore();
diff --git a/code/ryzom/server/src/ai_share/world_map.cpp b/code/ryzom/server/src/ai_share/world_map.cpp
index 677e8cb97..cbba47d49 100644
--- a/code/ryzom/server/src/ai_share/world_map.cpp
+++ b/code/ryzom/server/src/ai_share/world_map.cpp
@@ -34,6 +34,9 @@ NL_BEGIN_STRING_CONVERSION_TABLE (TAStarFlag)
 	NL_STRING_CONVERSION_TABLE_ENTRY(NoGo)
 	NL_STRING_CONVERSION_TABLE_ENTRY(WaterAndNogo)
 	NL_STRING_CONVERSION_TABLE_ENTRY(GroundFlags)
+	NL_STRING_CONVERSION_TABLE_ENTRY(Ground)
+	NL_STRING_CONVERSION_TABLE_ENTRY(GroundAndNogo)
+	NL_STRING_CONVERSION_TABLE_ENTRY(GroundAndWaterAndNogo)
 NL_END_STRING_CONVERSION_TABLE(TAStarFlag, AStarFlagConversion, Nothing)
 
 const std::string& toString(TAStarFlag flag)
@@ -781,14 +784,14 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosS();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isESlotValid())
 						return	false;
 
 					tmpPos=tmpPos.getPosE();
-					if	((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 				}
 
@@ -798,7 +801,7 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosE();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isSSlotValid())
@@ -819,14 +822,14 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosN();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isESlotValid())
 						return	false;
 
 					tmpPos=tmpPos.getPosE();
-					if	((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 				}
 
@@ -836,7 +839,7 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosE();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isNSlotValid())
@@ -856,14 +859,14 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosN();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isWSlotValid())
 						return	false;
 
 					tmpPos=tmpPos.getPosW();
-					if	((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 				}
 
@@ -873,7 +876,7 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosW();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isNSlotValid())
@@ -893,14 +896,14 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosS();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isWSlotValid())
 						return	false;
 
 					tmpPos=tmpPos.getPosW();
-					if	((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 				}
 
@@ -910,7 +913,7 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 						return	false;
 
 					tmpPos=tmpPos.getPosW();
-					if ((tmpPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)
+					if (!isPlaceAllowed(denyFlags, tmpPos.getTopologyRef().getCstTopologyNode().getFlags()))
 						return	false;
 
 					if (!tmpPos.getCellLinkage().isSSlotValid())
@@ -1348,29 +1351,21 @@ void	CWorldMap::countCells(uint &compute, uint &white, uint &simple, uint &multi
 
 		const	CTopology	&startTopoNode=startPos.getTopologyRef().getCstTopologyNode();
 		const	CTopology	&endTopoNode=endPos.getTopologyRef().getCstTopologyNode();
-		TAStarFlag	startFlag=(TAStarFlag)(startTopoNode.getFlags()&WaterAndNogo);
-//		if	(!allowStartRestriction)
-			startFlag=Nothing;
 
+		CPossibleTAStarFlags PossibleTAStarFlags; // build a list of possible flags given the denyflags
+		const int nFlags = PossibleTAStarFlags.buildTAStarFlagsList(denyflags); 
 
-		for	(TAStarFlag	possibleFlag=Nothing;possibleFlag<=WaterAndNogo;possibleFlag=(TAStarFlag)(possibleFlag+2))	//	tricky !! -> to replace with a defined list of flags to checks.
-		{
-			const	uint32	incompatibilityFlags=(possibleFlag&(denyflags&~startFlag))&WaterAndNogo;
-
-			if	(incompatibilityFlags)
-				continue;
-
-			const	uint32	startMasterTopo=startTopoNode.getMasterTopo(possibleFlag);
-			const	uint32	endMasterTopo=endTopoNode.getMasterTopo(possibleFlag);
-			if	(	(startMasterTopo^endMasterTopo)!=0
-				||	startMasterTopo == std::numeric_limits<uint32>::max())	// if not same masterTopo or invalid masterTopo then bypass ..
-				continue;
-
-			res.set(possibleFlag, startMasterTopo);
-			res.setValid();
-
-			if	(((possibleFlag&denyflags)&WaterAndNogo)==0)	//	it was the optimal case ?
-				break;
+		for(int i = 0;i < nFlags;i++){  // for each possible flag
+			TAStarFlag	possibleFlag = PossibleTAStarFlags.get(i);
+			uint32 startMasterTopo=startTopoNode.getMasterTopo(possibleFlag);
+			uint32 endMasterTopo=endTopoNode.getMasterTopo(possibleFlag);
+			if(	(startMasterTopo^endMasterTopo)!=0 ||
+				(startMasterTopo == CTopology::TTopologyId::UNDEFINED_TOPOLOGY)){	// if not same masterTopo or invalid masterTopo then continue
+				continue;				
+			}
+			res.set(possibleFlag, startMasterTopo);
+			res.setValid();
+			break;
 		}
 
 	}
@@ -1665,7 +1660,7 @@ bool	CWorldMap::findAStarPath(const CTopology::TTopologyId &start, const CTopolo
 			const CTopology	&ntp = next.getCstTopologyNode();
 
 			// don't examine not accessible nodes
-			if ((ntp.Flags & denyflags) != 0)
+			if (!isPlaceAllowed(denyflags,(RYAI_MAP_CRUNCH::TAStarFlag) ntp.Flags))
 				continue;
 
 			// compute actual node distance
@@ -1821,7 +1816,7 @@ bool CWorldMap::findInsideAStarPath(CWorldPosition const& start, CWorldPosition
 				continue;
 
 			// If that point's flags are not compatible skip it
-			if ((denyflags & mv.getTopologyRef().getCstTopologyNode().getFlags()) != 0)
+			if (!isPlaceAllowed(denyflags, mv.getTopologyRef().getCstTopologyNode().getFlags()))
 				continue;
 
 			// Build an A* node
@@ -1927,7 +1922,7 @@ bool	CWorldMap::move(CWorldPosition &pos, CAStarPath &path, uint &currentstep) c
 bool CWorldMap::move(CWorldPosition& pos, CMapPosition const& end, TAStarFlag const denyFlags) const
 {
 	CWorldPosition	tempPos(pos);
-	BOMB_IF((tempPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0, "Error in CWorldMap::mode, invalid flag "<<RYAI_MAP_CRUNCH::toString(tempPos.getTopologyRef().getCstTopologyNode().getFlags())
+	BOMB_IF(!isPlaceAllowed(denyFlags, tempPos.getTopologyRef().getCstTopologyNode().getFlags()), "Error in CWorldMap::mode, invalid flag "<<RYAI_MAP_CRUNCH::toString(tempPos.getTopologyRef().getCstTopologyNode().getFlags())
 		<<"on world pos "<<pos.toString()<<" while going to map pos "<<end.toString()<<" with denyflags "<<RYAI_MAP_CRUNCH::toString(denyFlags), return false);
 	//	not optimum but it will be rewrite for each specialized rootcell type.
 	const	sint32	x0	=	pos.x();
@@ -1945,7 +1940,7 @@ bool CWorldMap::move(CWorldPosition& pos, CMapPosition const& end, TAStarFlag co
 
 
 		if	(	!move(tempPos, CDirection(dx,dy))
-			||	(tempPos.getTopologyRef().getCstTopologyNode().getFlags()&denyFlags)!=0)	//	Arghh !!
+			||	!isPlaceAllowed(denyFlags, tempPos.getTopologyRef().getCstTopologyNode().getFlags()))	//	Arghh !!
 			return	false;
 		pos=tempPos;
 	}
diff --git a/code/ryzom/server/src/ai_share/world_map.h b/code/ryzom/server/src/ai_share/world_map.h
index f9e46ecfc..57cb54735 100644
--- a/code/ryzom/server/src/ai_share/world_map.h
+++ b/code/ryzom/server/src/ai_share/world_map.h
@@ -52,18 +52,74 @@ enum TAStarFlag
 	Water			= 2,
 	NoGo			= 4,
 	WaterAndNogo	= 6,
-	GroundFlags		= WaterAndNogo
+	GroundFlags		= WaterAndNogo,
+	Ground			= 8,
+	GroundAndNogo	= 12,
+	GroundAndWaterAndNogo = 14
 };
 
 const std::string& toString(TAStarFlag flag);
 TAStarFlag toAStarFlag(const std::string& str);
 
+inline int isPlaceAllowed(TAStarFlag denyFlags, TAStarFlag flags){ // check if the place is allowed given the denyFlags and flags
+	if(denyFlags & Ground){ // in case of ground is denied
+		return	((flags & denyFlags) == 0) && // denied flags against the current flags
+				(flags & Water);  // check the current flag is in the water
+	} else {
+		return (flags & denyFlags) == 0; //  denied flags against the current flags
+	}
+}
+
+
 uint const WorldMapGridSize = 256;
 double const WorldGridResolution = 1.;
 NLMISC::CVectorD const WorldStartOffset = NLMISC::CVectorD(0., 0., 0.);
 
 typedef sint TLevel;
 
+class CPossibleTAStarFlags { // class to create a list of possible TAStarFlags
+private:
+	uint8 nFlags;
+	uint8 aFlags[3];
+public:
+	CPossibleTAStarFlags() : nFlags(0){ // default constructor
+	}
+	int buildTAStarFlagsList(const TAStarFlag denyflags){
+		nFlags = 0;
+		if(denyflags & Ground){ // ground forbidden
+			if(!(denyflags & Water)){ // Water possible
+				aFlags[nFlags++] = (uint8)(Water | Ground);
+				if(!(denyflags & NoGo)){ // Water and NoGo possible
+					aFlags[nFlags++] = (uint8)(Water | NoGo | Ground);
+				}
+			}
+		} else { // ground possible
+			aFlags[nFlags++] = (uint8)(Nothing);
+			if(!(denyflags & Water)){ // Ground and Water possible
+				aFlags[nFlags++] = (uint8)(Water);
+				if(!(denyflags & NoGo)){ // Ground, Water and NoGo possible
+					aFlags[nFlags++] = (uint8)(Water | NoGo);
+				}
+			} else {
+				if(!(denyflags & NoGo)){ // Ground and NoGo possible
+					aFlags[nFlags++] = (uint8)(NoGo);
+				}
+			}
+		}
+		return nFlags;
+	}
+	int size(){ // returns the size of the list of possible TAStarFlags
+		return nFlags;
+	}
+
+	TAStarFlag get(int nIndex){ // returns a possible TAStarFlag
+		return (TAStarFlag)aFlags[nIndex];
+	}
+
+	CPossibleTAStarFlags(const TAStarFlag denyflags){ //constructor, build a possible TAStarFlag list
+		buildTAStarFlagsList(denyflags);
+	}
+};
 
 //////////////////////////////////////////////////////////////////////////////
 
@@ -1573,17 +1629,23 @@ void CTopology::updateTopologyRef(CWorldMap* worldMapPtr)
 inline
 uint32 CTopology::getMasterTopo(TAStarFlag const& flags) const
 {
-	switch (flags&WaterAndNogo)
-	{
-	case Nothing:
-	default:
-		return MasterTopL;
-	case Water:
-		return MasterTopLW;
-	case NoGo:
-		return MasterTopLN;
-	case WaterAndNogo:
-		return MasterTopLNW;
+	switch (flags&(WaterAndNogo | Ground))
+	{
+	case Nothing:
+	default:
+		return MasterTopL;
+	case Water:
+		return MasterTopLW;
+	case NoGo:
+		return MasterTopLN;
+	case WaterAndNogo:
+		return MasterTopLNW;
+	case Water|Ground:
+		return (MasterTopL == TTopologyId::UNDEFINED_TOPOLOGY) ? MasterTopLW : TTopologyId::UNDEFINED_TOPOLOGY;
+	case Water|Ground|NoGo:
+		return (MasterTopL == TTopologyId::UNDEFINED_TOPOLOGY) ? MasterTopLNW : TTopologyId::UNDEFINED_TOPOLOGY;
+	case NoGo|Ground:
+		return TTopologyId::UNDEFINED_TOPOLOGY;
 	}
 }