diff --git a/source/build/include/build.h b/source/build/include/build.h
index 51e3228ff..844e85f29 100644
--- a/source/build/include/build.h
+++ b/source/build/include/build.h
@@ -352,21 +352,6 @@ inline constexpr uint32_t uhypsq(int32_t const dx, int32_t const dy)
 }
 
 void rotatepoint(vec2_t const pivot, vec2_t p, int16_t const daang, vec2_t * const p2) ATTRIBUTE((nonnull(4)));
-inline void rotatepoint(int px, int py, int ptx, int pty, int daang, int* resx, int* resy)
-{
-    vec2_t pivot = { px, py };
-    vec2_t point = { ptx, pty };
-    vec2_t result;
-    rotatepoint(pivot, point, daang, &result);
-    *resx = result.x;
-    *resy = result.y;
-}
-
-int32_t   lastwall(int16_t point);
-inline walltype* lastwall(walltype* point)
-{
-    return &wall[lastwall(wall.IndexOf(point))];
-}
 
 sectortype* nextsectorneighborzptr(sectortype* sectp, int refz, int topbottom, int direction);
 inline sectortype* safenextsectorneighborzptr(sectortype* sectp, int refz, int topbottom, int direction)
@@ -590,6 +575,21 @@ inline sectortype* walltype::sectorp() const
 	return &::sector[sector]; // cannot be -1 in a proper map.
 }
 
+inline walltype* walltype::lastWall() const
+{
+    int index = wall.IndexOf(this);
+    if (index > 0 && wall[index - 1].point2 == index) return &wall[index - 1];
+
+    int check = index;
+    for (int i = 0; i < numwalls; i++)
+    {
+        int next = wall[check].point2;
+        if (next == index) return &wall[check];
+        check = next;
+    }
+    return nullptr;
+}
+
 inline walltype* walltype::point2Wall() const
 {
 	return &::wall[point2]; // cannot be -1 in a proper map.
@@ -605,5 +605,19 @@ inline walltype* sectortype::lastWall() const
     return &wall[wallptr + wallnum - 1]; // cannot be -1 in a proper map
 }
 
+inline void walltype::moved() 
+{
+    lengthflags = 3;
+    sectorp()->dirty = EDirty::AllDirty;
+}
+
+inline void walltype::move(int newx, int newy)
+{
+    pos.x = newx;
+    pos.y = newy;
+    lengthflags = 3;
+    sectorp()->dirty = EDirty::AllDirty;
+}
+
 
 #endif // build_h_
diff --git a/source/build/include/buildtypes.h b/source/build/include/buildtypes.h
index 141a37ea1..b6b893e7e 100644
--- a/source/build/include/buildtypes.h
+++ b/source/build/include/buildtypes.h
@@ -208,10 +208,12 @@ struct walltype
     };
     int16_t hitag;
     int16_t extra;
+    uint16_t portalnum;
     float xpan_, ypan_;
     binangle clipangle;
     uint8_t portalflags;
-    uint16_t portalnum;
+    uint8_t lengthflags;
+    int length; // cached value to avoid calling sqrt repeatedly.
 
     // Blood is the only game which extends the wall struct.
     Blood::XWALL* _xw;
@@ -226,12 +228,15 @@ struct walltype
     sectortype* nextSector() const;
 	sectortype* sectorp() const;
 	walltype* nextWall() const;
+    walltype* lastWall() const;
     walltype* point2Wall() const;
 	vec2_t delta() const { return point2Wall()->pos - pos; }
 	vec2_t center() const { return(point2Wall()->pos + pos) / 2; }
 	int deltax() const { return point2Wall()->x - x; }
 	int deltay() const { return point2Wall()->y - y; }
     bool twoSided() const { return nextsector >= 0; }
+    void move(int newx, int newy);
+    void moved();
 
     Blood::XWALL& xw() const { return *_xw; }
     bool hasX() const { return _xw != nullptr; }
diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index 553313c6c..e6f0da772 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -626,9 +626,7 @@ void dragpoint(int w, int32_t dax, int32_t day)
     while (1)
     {
         auto wal = &wall[w];
-        sector[wal->sector].dirty = EDirty::AllDirty;
-        wal->x = dax;
-        wal->y = day;
+        wal->move(dax, day);
         walbitmap.Set(w);
 
         if (!clockwise)  //search points CCW
@@ -651,9 +649,9 @@ void dragpoint(int w, int32_t dax, int32_t day)
 
         if (clockwise)
         {
-            int32_t thelastwall = lastwall(w);
-            if (wall[thelastwall].nextwall >= 0)
-                w = wall[thelastwall].nextwall;
+            auto thelastwall = wall[w].lastWall();
+            if (thelastwall->nextwall >= 0)
+                w = thelastwall->nextwall;
             else
                 break;
         }
@@ -670,32 +668,6 @@ void dragpoint(int w, int32_t dax, int32_t day)
     }
 }
 
-//
-// lastwall
-//
-int32_t lastwall(int16_t point)
-{
-    if (point > 0 && wall[point-1].point2 == point)
-        return point-1;
-
-    int i = point, cnt = numwalls;
-    do
-    {
-        int const j = wall[i].point2;
-
-        if (j == point)
-        {
-            point = i;
-            break;
-        }
-
-        i = j;
-    }
-    while (--cnt);
-
-    return point;
-}
-
 ////////// UPDATESECTOR* FAMILY OF FUNCTIONS //////////
 
 /* Different "is inside" predicates.
diff --git a/source/core/interpolate.cpp b/source/core/interpolate.cpp
index 2c40e277b..aeb1394a9 100644
--- a/source/core/interpolate.cpp
+++ b/source/core/interpolate.cpp
@@ -72,8 +72,8 @@ void Set(int index, int type, double val)
 	case Interp_Sect_CeilingPanX:       sector[index].ceilingxpan_ = float(val); break;
 	case Interp_Sect_CeilingPanY:       sector[index].ceilingypan_ = float(val); break;
                                         
-	case Interp_Wall_X:                 old = wall[index].x; wall[index].x = xs_CRoundToInt(val); if (wall[index].x != old) sector[wall[index].sector].dirty = EDirty::AllDirty; break;
-	case Interp_Wall_Y:                 old = wall[index].y; wall[index].y = xs_CRoundToInt(val); if (wall[index].y != old) sector[wall[index].sector].dirty = EDirty::AllDirty; break;
+	case Interp_Wall_X:                 old = wall[index].x; wall[index].x = xs_CRoundToInt(val); if (wall[index].x != old) wall[index].moved(); break;
+	case Interp_Wall_Y:                 old = wall[index].y; wall[index].y = xs_CRoundToInt(val); if (wall[index].y != old) wall[index].moved(); break;
 	case Interp_Wall_PanX:              wall[index].xpan_ = float(val);  break;
 	case Interp_Wall_PanY:              wall[index].ypan_ = float(val);  break;
 	}
diff --git a/source/core/maploader.cpp b/source/core/maploader.cpp
index 0df78de8a..02211acd4 100644
--- a/source/core/maploader.cpp
+++ b/source/core/maploader.cpp
@@ -525,7 +525,9 @@ void setWallSectors()
 	for (auto& wal : walls())
 	{
 		wal.sector = -1;
+		wal.lengthflags = 3;
 	}
+
 	for (int i = 0; i < numsectors - 1; i++)
 	{
 		auto sect = &sector[i];
diff --git a/source/core/rendering/scene/hw_drawinfo.cpp b/source/core/rendering/scene/hw_drawinfo.cpp
index 84f152062..972d5f266 100644
--- a/source/core/rendering/scene/hw_drawinfo.cpp
+++ b/source/core/rendering/scene/hw_drawinfo.cpp
@@ -417,7 +417,7 @@ void HWDrawInfo::CreateScene(bool portal)
 				wal->x += eff.geox[i];
 				wal->y += eff.geoy[i];
 			}
-			sect->dirty = 255;
+			sect->dirty = EDirty::AllDirty;
 			if (eff.geosector[i] == drawsectp) drawsectp = eff.geosectorwarp[i];
 		}
 
@@ -449,7 +449,7 @@ void HWDrawInfo::CreateScene(bool portal)
 				wal->x += eff.geox2[i];
 				wal->y += eff.geoy2[i];
 			}
-			sect->dirty = 255;
+			sect->dirty = EDirty::AllDirty;
 			if (eff.geosector[i] == orgdrawsectp) drawsectp = eff.geosectorwarp2[i];
 		}
 
diff --git a/source/games/blood/src/db.cpp b/source/games/blood/src/db.cpp
index 2ef4eb9a8..94ed11070 100644
--- a/source/games/blood/src/db.cpp
+++ b/source/games/blood/src/db.cpp
@@ -329,7 +329,7 @@ void dbLoadMap(const char* pPath, int* pX, int* pY, int* pZ, short* pAngle, sect
         pSector->floorypan_ = load.floorypanning;
         pSector->visibility = load.visibility;
         pSector->slopewallofs = load.fogpal;
-        pSector->dirty = 255;
+        pSector->dirty = EDirty::AllDirty;
         pSector->exflags = 0;
         pSector->fogpal = 0;
 
diff --git a/source/games/blood/src/triggers.cpp b/source/games/blood/src/triggers.cpp
index 0919b2602..11c109ae8 100644
--- a/source/games/blood/src/triggers.cpp
+++ b/source/games/blood/src/triggers.cpp
@@ -759,10 +759,8 @@ void PathSound(sectortype* pSector, int nSound)
 
 void DragPoint(walltype* pWall, int x, int y)
 {
-    pWall->sectorp()->dirty = 255; 
     viewInterpolateWall(pWall);
-    pWall->x = x;
-    pWall->y = y;
+    pWall->move(x, y);
 
     int vsi = numwalls;
     auto prevWall = pWall;
@@ -771,24 +769,20 @@ void DragPoint(walltype* pWall, int x, int y)
         if (prevWall->twoSided())
         {
             prevWall = prevWall->nextWall()->point2Wall();
-            prevWall->sectorp()->dirty = 255;
             viewInterpolateWall(prevWall);
-            prevWall->x = x;
-            prevWall->y = y;
+            prevWall->move(x, y);
         }
         else
         {
             prevWall = pWall;
             do
             {
-                auto lw = lastwall(prevWall);
-                if (lw->twoSided())
+                auto lw = prevWall->lastWall();
+                if (lw && lw->twoSided())
                 {
                     prevWall = lw->nextWall();
-                    prevWall->sectorp()->dirty = 255;
                     viewInterpolateWall(prevWall);
-                    prevWall->x = x;
-                    prevWall->y = y;
+                    prevWall->move(x, y);
                 }
                 else
                     break;
diff --git a/source/games/duke/src/actors.cpp b/source/games/duke/src/actors.cpp
index 437f67537..513fc5453 100644
--- a/source/games/duke/src/actors.cpp
+++ b/source/games/duke/src/actors.cpp
@@ -281,7 +281,6 @@ void ms(DDukeActor* const actor)
 {
 	//T1,T2 and T3 are used for all the sector moving stuff!!!
 
-	int tx, ty;
 	auto s = actor->s;
 
 	s->x += MulScale(s->xvel, bcos(s->ang), 14);
@@ -292,12 +291,10 @@ void ms(DDukeActor* const actor)
 
 	for(auto& wal : wallsofsector(actor->sector()))
 	{
-		rotatepoint(
-			0, 0,
-			msx[j], msy[j],
-			k & 2047, &tx, &ty);
+		vec2_t t;
+		rotatepoint({ 0, 0 }, { msx[j], msy[j] }, k & 2047, &t);
 
-		dragpoint(&wal, s->x + tx, s->y + ty);
+		dragpoint(&wal, s->x + t.x, s->y + t.y);
 		j++;
 	}
 }
@@ -2751,20 +2748,18 @@ void handle_se00(DDukeActor* actor, int LASERLINE)
 
 				ps[p].pos.z += zchange;
 
-				int m, x;
-				rotatepoint(Owner->s->x, Owner->s->y,	ps[p].pos.x, ps[p].pos.y, (q * l), &m, &x);
+				vec2_t res;
+				rotatepoint(Owner->s->pos.vec2, ps[p].pos.vec2, (q * l), &res);
 
-				ps[p].bobposx += m - ps[p].pos.x;
-				ps[p].bobposy += x - ps[p].pos.y;
+				ps[p].bobposx += res.x - ps[p].pos.x;
+				ps[p].bobposy += res.y - ps[p].pos.y;
 
-				ps[p].pos.x = m;
-				ps[p].pos.y = x;
+				ps[p].pos.vec2 = res;
 
 				auto psp = ps[p].GetActor();
 				if (psp->s->extra <= 0)
 				{
-					psp->s->x = m;
-					psp->s->y = x;
+					psp->s->pos.vec2 = res;
 				}
 			}
 		}
@@ -2784,7 +2779,7 @@ void handle_se00(DDukeActor* actor, int LASERLINE)
 					sprp->ang &= 2047;
 
 					sprp->z += zchange;
-					rotatepoint(Owner->s->x, Owner->s->y, ap->s->x, ap->s->y, (q* l), &ap->s->x, &ap->s->y);
+					rotatepoint(Owner->s->pos.vec2, ap->s->pos.vec2, (q* l), &ap->s->pos.vec2);
 				}
 		}
 
@@ -2932,7 +2927,7 @@ void handle_se14(DDukeActor* actor, bool checkstat, int RPG, int JIBS6)
 
 				if (s->sector() == psp->s->sector())
 				{
-					rotatepoint(s->x, s->y, ps[p].pos.x, ps[p].pos.y, q, &ps[p].pos.x, &ps[p].pos.y);
+					rotatepoint(s->pos.vec2, ps[p].pos.vec2, q, &ps[p].pos.vec2);
 
 					ps[p].pos.x += m;
 					ps[p].pos.y += x;
@@ -2961,7 +2956,7 @@ void handle_se14(DDukeActor* actor, bool checkstat, int RPG, int JIBS6)
 			auto sj = a2->s;
 			if (sj->statnum != 10 && sj->sector()->lotag != 2 && sj->picnum != SECTOREFFECTOR && sj->picnum != LOCATORS)
 			{
-				rotatepoint(s->x, s->y, sj->x, sj->y, q, &sj->x, &sj->y);
+				rotatepoint(s->pos.vec2, sj->pos.vec2, q, &sj->pos.vec2);
 
 				sj->x += m;
 				sj->y += x;
diff --git a/source/games/duke/src/funct.h b/source/games/duke/src/funct.h
index c7424dfa4..610711b14 100644
--- a/source/games/duke/src/funct.h
+++ b/source/games/duke/src/funct.h
@@ -237,6 +237,6 @@ void loadcons();
 void recordoldspritepos();
 void DrawStatusBar();
 
-int* animateptr(int i);
+int* animateptr(int i, bool write = true);
 
 END_DUKE_NS
diff --git a/source/games/duke/src/sectors.cpp b/source/games/duke/src/sectors.cpp
index 2a2822b74..63aa2ff46 100644
--- a/source/games/duke/src/sectors.cpp
+++ b/source/games/duke/src/sectors.cpp
@@ -278,7 +278,7 @@ int findotherplayer(int p, int* d)
 //
 //---------------------------------------------------------------------------
 
-int* animateptr(int type, int index)
+int* animateptr(int type, int index, bool write)
 {
 	static int scratch;
 	switch (type)
@@ -288,8 +288,10 @@ int* animateptr(int type, int index)
 	case anim_ceilingz:
 		return &sector[index].ceilingz;
 	case anim_vertexx:
+		if (write) wall[index].moved();
 		return &wall[index].x;
 	case anim_vertexy:
+		if (write) wall[index].moved();
 		return &wall[index].y;
 	default:
 		assert(false);
@@ -297,9 +299,9 @@ int* animateptr(int type, int index)
 	}
 }
 
-int* animateptr(int i)
+int* animateptr(int i, bool write)
 {
-	return animateptr(animatetype[i], animatetarget[i]);
+	return animateptr(animatetype[i], animatetarget[i], write);
 }
 
 //---------------------------------------------------------------------------
@@ -314,7 +316,7 @@ void doanimations(void)
 
 	for (i = animatecnt - 1; i >= 0; i--)
 	{
-		a = *animateptr(i);
+		a = *animateptr(i, false);
 		v = animatevel[i] * TICSPERFRAME;
 		auto dasectp = animatesect[i];
 
@@ -365,7 +367,7 @@ void doanimations(void)
 			}
 		}
 
-		*animateptr(i) = a;
+		*animateptr(i, true) = a;
 	}
 }
 
@@ -411,7 +413,7 @@ static int dosetanimation(sectortype* animsect, int animtype, int animtarget, in
 			break;
 		}
 
-	auto animptr = animateptr(animtype, animtarget);
+	auto animptr = animateptr(animtype, animtarget, false);
 	animatesect[j] = animsect;
 	animatetype[j] = animtype;
 	animatetarget[j] = animtarget;
diff --git a/source/games/sw/src/interpso.cpp b/source/games/sw/src/interpso.cpp
index b145ffaf2..d1b26d275 100644
--- a/source/games/sw/src/interpso.cpp
+++ b/source/games/sw/src/interpso.cpp
@@ -96,10 +96,10 @@ static int &getvalue(so_interp::interp_data& element, bool write)
     switch (type)
     {
     case soi_wallx:
-        if (write) wall[index].sectorp()->dirty = 255;
+        if (write) wall[index].moved();
         return wall[index].x;
     case soi_wally:
-        if (write) wall[index].sectorp()->dirty = 255;
+        if (write) wall[index].moved();
         return wall[index].y;
     case soi_ceil:
         return sector[index].ceilingz;
diff --git a/source/games/sw/src/slidor.cpp b/source/games/sw/src/slidor.cpp
index 226aa0048..f56886af2 100644
--- a/source/games/sw/src/slidor.cpp
+++ b/source/games/sw/src/slidor.cpp
@@ -297,10 +297,11 @@ int DoSlidorMoveWalls(DSWActor* actor, int amt)
             if (!wal->twoSided())
             {
                 // white wall - move 4 points
-                wal->x -= amt;
-                pwal->x -= amt;
-                wal->point2Wall()->x -= amt;
-                wal->point2Wall()->point2Wall()->x -= amt;
+                wal->move(wal->x - amt, wal->y);
+                pwal->move(pwal->x - amt, pwal->y);
+                wal->point2Wall()->move(wal->point2Wall()->x - amt, wal->point2Wall()->y);
+                auto pwal2 = wal->point2Wall()->point2Wall();
+                pwal2->move(pwal2->x - amt, pwal2->y);
             }
             else
             {
@@ -321,10 +322,11 @@ int DoSlidorMoveWalls(DSWActor* actor, int amt)
             if (!wal->twoSided())
             {
                 // white wall - move 4 points
-                wal->x += amt;
-                pwal->x += amt;
-                wal->point2Wall()->x += amt;
-                wal->point2Wall()->point2Wall()->x += amt;
+                wal->move(wal->x + amt, wal->y);
+                pwal->move(pwal->x + amt, pwal->y);
+                wal->point2Wall()->move(wal->point2Wall()->x + amt, wal->point2Wall()->y);
+                auto pwal2 = wal->point2Wall()->point2Wall();
+                pwal2->move(pwal2->x + amt, pwal2->y);
             }
             else
             {
@@ -344,10 +346,11 @@ int DoSlidorMoveWalls(DSWActor* actor, int amt)
 
             if (!wal->twoSided())
             {
-                wal->y -= amt;
-                pwal->y -= amt;
-                wal->point2Wall()->y -= amt;
-                wal->point2Wall()->point2Wall()->y -= amt;
+                wal->move(wal->x, wal->y - amt);
+                pwal->move(pwal->x, pwal->y - amt);
+                wal->point2Wall()->move(wal->point2Wall()->x, wal->point2Wall()->y - amt);
+                auto pwal2 = wal->point2Wall()->point2Wall();
+                pwal2->move(pwal2->x, pwal2->y - amt);
             }
             else
             {
@@ -366,10 +369,11 @@ int DoSlidorMoveWalls(DSWActor* actor, int amt)
 
             if (!wal->twoSided())
             {
-                wal->y += amt;
-                pwal->y += amt;
-                wal->point2Wall()->y += amt;
-                wal->point2Wall()->point2Wall()->y += amt;
+                wal->move(wal->x, wal->y + amt);
+                pwal->move(pwal->x, pwal->y + amt);
+                wal->point2Wall()->move(wal->point2Wall()->x, wal->point2Wall()->y + amt);
+                auto pwal2 = wal->point2Wall()->point2Wall();
+                pwal2->move(pwal2->x, pwal2->y + amt);
             }
             else
             {
diff --git a/source/games/sw/src/sprite.cpp b/source/games/sw/src/sprite.cpp
index d17d91ad7..ec1b10291 100644
--- a/source/games/sw/src/sprite.cpp
+++ b/source/games/sw/src/sprite.cpp
@@ -1513,8 +1513,7 @@ void PreMapCombineFloors(void)
 
             for (auto& wal : wallsofsector(dasect))
             {
-                wal.x += dx;
-                wal.y += dy;
+                wal.move(wal.x + dx, wal.y + dy);
 
                 if (wal.twoSided())
                     search.Add(wal.nextSector());
diff --git a/source/games/sw/src/track.cpp b/source/games/sw/src/track.cpp
index 11b77d7c9..9ab0a1aa0 100644
--- a/source/games/sw/src/track.cpp
+++ b/source/games/sw/src/track.cpp
@@ -1687,12 +1687,11 @@ void MovePoints(SECTOR_OBJECTp sop, short delta_ang, int nx, int ny)
 
             if (wal.extra && TEST(wal.extra, WALLFX_LOOP_OUTER))
             {
-                dragpoint(&wal, wal.x += nx, wal.y += ny);
+                dragpoint(&wal, wal.x + nx, wal.y + ny);
             }
             else
             {
-                wal.x += nx;
-                wal.y += ny;
+                wal.move(wal.x + nx, wal.y + ny);
             }
 
             rot_ang = delta_ang;
@@ -1714,8 +1713,7 @@ void MovePoints(SECTOR_OBJECTp sop, short delta_ang, int nx, int ny)
             }
             else
             {
-                wal.x = rxy.x;
-                wal.y = rxy.y;
+                wal.move(rxy.x, rxy.y);
             }
         }
 
@@ -1938,8 +1936,7 @@ void RefreshPoints(SECTOR_OBJECTp sop, int nx, int ny, bool dynamic)
                     }
                     else
                     {
-                        wal.x = dx;
-                        wal.y = dy;
+                        wal.move(dx, dy);
                     }
                 }
 
@@ -2093,8 +2090,7 @@ void CollapseSectorObject(SECTOR_OBJECTp sop, int nx, int ny)
                 }
                 else
                 {
-                    wal.x = nx;
-                    wal.y = ny;
+                    wal.move(nx, ny);
                 }
             }
         }
diff --git a/source/games/sw/src/wallmove.cpp b/source/games/sw/src/wallmove.cpp
index ef18fd942..0435f7f67 100644
--- a/source/games/sw/src/wallmove.cpp
+++ b/source/games/sw/src/wallmove.cpp
@@ -119,9 +119,7 @@ int DoWallMove(DSWActor* actor)
             }
             else
             {
-                wal.x = sp->x + nx;
-                wal.y = sp->y + ny;
-                wal.sectorp()->dirty = 255;
+                wal.move(sp->x + nx, sp->y + ny);
             }
 
             if (shade1)