diff --git a/LUA_API.rst b/LUA_API.rst
index 38b0e2025..d2afacd42 100644
--- a/LUA_API.rst
+++ b/LUA_API.rst
@@ -795,6 +795,16 @@ Maps module
 
   Returns the local feature object with the given region coords and index.
 
+* ``dfhack.maps.canWalkBetween(pos1, pos2)``
+
+  Checks if a dwarf may be able to walk between the two tiles,
+  using a pathfinding cache maintained by the game. Note that
+  this cache is only updated when the game is unpaused, and thus
+  can get out of date if doors are forbidden or unforbidden, or
+  tools like liquids or tiletypes are used. It also cannot possibly
+  take into account anything that depends on the actual units, like
+  burrows, or the presence of invaders.
+
 
 Burrows module
 --------------
diff --git a/Lua API.html b/Lua API.html
index 3e08b3bef..fd2004b8d 100644
--- a/Lua API.html	
+++ b/Lua API.html	
@@ -1015,6 +1015,15 @@ Returns <em>false</em> in case of error.</p>
 <li><p class="first"><tt class="docutils literal">dfhack.maps.getLocalInitFeature(region_coord2d,index)</tt></p>
 <p>Returns the local feature object with the given region coords and index.</p>
 </li>
+<li><p class="first"><tt class="docutils literal">dfhack.maps.canWalkBetween(pos1, pos2)</tt></p>
+<p>Checks if a dwarf may be able to walk between the two tiles,
+using a pathfinding cache maintained by the game. Note that
+this cache is only updated when the game is unpaused, and thus
+can get out of date if doors are forbidden or unforbidden, or
+tools like liquids or tiletypes are used. It also cannot possibly
+take into account anything that depends on the actual units, like
+burrows, or the presence of invaders.</p>
+</li>
 </ul>
 </div>
 <div class="section" id="burrows-module">
diff --git a/library/LuaApi.cpp b/library/LuaApi.cpp
index 507494669..8855a50da 100644
--- a/library/LuaApi.cpp
+++ b/library/LuaApi.cpp
@@ -80,6 +80,17 @@ distribution.
 using namespace DFHack;
 using namespace DFHack::LuaWrapper;
 
+void Lua::Push(lua_State *state, const Units::NoblePosition &pos)
+{
+    lua_createtable(state, 0, 3);
+    Lua::PushDFObject(state, pos.entity);
+    lua_setfield(state, -2, "entity");
+    Lua::PushDFObject(state, pos.assignment);
+    lua_setfield(state, -2, "assignment");
+    Lua::PushDFObject(state, pos.position);
+    lua_setfield(state, -2, "position");
+}
+
 int Lua::PushPosXYZ(lua_State *state, df::coord pos)
 {
     if (!pos.isValid())
@@ -558,11 +569,15 @@ static void OpenModule(lua_State *state, const char *mname,
 #define WRAP(function) { #function, df::wrap_function(function,true) }
 #define WRAPN(name, function) { #name, df::wrap_function(function,true) }
 
+/***** Translation module *****/
+
 static const LuaWrapper::FunctionReg dfhack_module[] = {
     WRAPM(Translation, TranslateName),
     { NULL, NULL }
 };
 
+/***** Gui module *****/
+
 static const LuaWrapper::FunctionReg dfhack_gui_module[] = {
     WRAPM(Gui, getSelectedWorkshopJob),
     WRAPM(Gui, getSelectedJob),
@@ -573,6 +588,8 @@ static const LuaWrapper::FunctionReg dfhack_gui_module[] = {
     { NULL, NULL }
 };
 
+/***** Job module *****/
+
 static bool jobEqual(df::job *job1, df::job *job2) { return *job1 == *job2; }
 static bool jobItemEqual(df::job_item *job1, df::job_item *job2) { return *job1 == *job2; }
 
@@ -609,6 +626,7 @@ static const luaL_Reg dfhack_job_funcs[] = {
     { NULL, NULL }
 };
 
+/***** Units module *****/
 
 static const LuaWrapper::FunctionReg dfhack_units_module[] = {
     WRAPM(Units, getContainer),
@@ -635,21 +653,7 @@ static int units_getNoblePositions(lua_State *state)
     std::vector<Units::NoblePosition> np;
 
     if (Units::getNoblePositions(&np, Lua::CheckDFObject<df::unit>(state,1)))
-    {
-        lua_createtable(state, np.size(), 0);
-
-        for (size_t i = 0; i < np.size(); i++)
-        {
-            lua_createtable(state, 0, 3);
-            Lua::PushDFObject(state, np[i].entity);
-            lua_setfield(state, -2, "entity");
-            Lua::PushDFObject(state, np[i].assignment);
-            lua_setfield(state, -2, "assignment");
-            Lua::PushDFObject(state, np[i].position);
-            lua_setfield(state, -2, "position");
-            lua_rawseti(state, -2, i+1);
-        }
-    }
+        Lua::PushVector(state, np);
     else
         lua_pushnil(state);
 
@@ -662,6 +666,8 @@ static const luaL_Reg dfhack_units_funcs[] = {
     { NULL, NULL }
 };
 
+/***** Items module *****/
+
 static bool items_moveToGround(df::item *item, df::coord pos)
 {
     MapExtras::MapCache mc;
@@ -702,12 +708,15 @@ static const luaL_Reg dfhack_items_funcs[] = {
     { NULL, NULL }
 };
 
+/***** Maps module *****/
+
 static const LuaWrapper::FunctionReg dfhack_maps_module[] = {
     WRAPN(getBlock, (df::map_block* (*)(int32_t,int32_t,int32_t))Maps::getBlock),
     WRAPN(getTileBlock, (df::map_block* (*)(df::coord))Maps::getTileBlock),
     WRAPM(Maps, getRegionBiome),
     WRAPM(Maps, getGlobalInitFeature),
     WRAPM(Maps, getLocalInitFeature),
+    WRAPM(Maps, canWalkBetween),
     { NULL, NULL }
 };
 
@@ -715,6 +724,8 @@ static const luaL_Reg dfhack_maps_funcs[] = {
     { NULL, NULL }
 };
 
+/***** Burrows module *****/
+
 static bool burrows_isAssignedBlockTile(df::burrow *burrow, df::map_block *block, int x, int y)
 {
     return Burrows::isAssignedBlockTile(burrow, block, df::coord2d(x,y));
diff --git a/library/include/LuaTools.h b/library/include/LuaTools.h
index a41b58d1c..1ca79d331 100644
--- a/library/include/LuaTools.h
+++ b/library/include/LuaTools.h
@@ -36,6 +36,10 @@ distribution.
 
 namespace DFHack {
     class function_identity_base;
+
+    namespace Units {
+        struct NoblePosition;
+    }
 }
 
 namespace DFHack {namespace Lua {
@@ -243,6 +247,7 @@ namespace DFHack {namespace Lua {
     }
     inline void Push(lua_State *state, df::coord &obj) { PushDFObject(state, &obj); }
     inline void Push(lua_State *state, df::coord2d &obj) { PushDFObject(state, &obj); }
+    void Push(lua_State *state, const Units::NoblePosition &pos);
     template<class T> inline void Push(lua_State *state, T *ptr) {
         PushDFObject(state, ptr);
     }
diff --git a/library/include/modules/Maps.h b/library/include/modules/Maps.h
index b6077a85e..332954cda 100644
--- a/library/include/modules/Maps.h
+++ b/library/include/modules/Maps.h
@@ -255,6 +255,8 @@ extern DFHACK_EXPORT bool SortBlockEvents(df::map_block *block,
 
 /// remove a block event from the block by address
 extern DFHACK_EXPORT bool RemoveBlockEvent(uint32_t x, uint32_t y, uint32_t z, df::block_square_event * which );
+
+DFHACK_EXPORT bool canWalkBetween(df::coord pos1, df::coord pos2);
 }
 }
 #endif
diff --git a/library/modules/Maps.cpp b/library/modules/Maps.cpp
index e7d49deda..ddf5d5069 100644
--- a/library/modules/Maps.cpp
+++ b/library/modules/Maps.cpp
@@ -387,6 +387,20 @@ bool Maps::ReadGeology(vector<vector<int16_t> > *layer_mats, vector<df::coord2d>
     return true;
 }
 
+bool Maps::canWalkBetween(df::coord pos1, df::coord pos2)
+{
+    auto block1 = getTileBlock(pos1);
+    auto block2 = getTileBlock(pos2);
+
+    if (!block1 || !block2)
+        return false;
+
+    auto tile1 = MapExtras::index_tile<uint16_t>(block1->walkable, pos1);
+    auto tile2 = MapExtras::index_tile<uint16_t>(block2->walkable, pos2);
+
+    return tile1 && tile1 == tile2;
+}
+
 #define COPY(a,b) memcpy(&a,&b,sizeof(a))
 
 MapExtras::Block::Block(MapCache *parent, DFCoord _bcoord) : parent(parent)
diff --git a/plugins/liquids.cpp b/plugins/liquids.cpp
index 8ca66daf5..f644398f5 100644
--- a/plugins/liquids.cpp
+++ b/plugins/liquids.cpp
@@ -388,6 +388,7 @@ command_result df_liquids_execute(color_ostream &out)
                 mcache.setTemp2At(*iter,10015);
                 df::tile_designation des = mcache.designationAt(*iter);
                 des.bits.flow_size = 0;
+                des.bits.flow_forbid = false;
                 mcache.setDesignationAt(*iter, des);
                 iter ++;
             }
@@ -494,6 +495,9 @@ command_result df_liquids_execute(color_ostream &out)
                         mcache.setTemp1At(current,10015);
                         mcache.setTemp2At(current,10015);
                     }
+                    // mark the tile passable or impassable like the game does
+                    des.bits.flow_forbid = des.bits.flow_size &&
+                        (des.bits.liquid_type == tile_liquid::Magma || des.bits.flow_size > 3);
                     mcache.setDesignationAt(current,des);
                 }
                 seen_blocks.insert(mcache.BlockAt(current / 16));