diff --git a/game-music-emu/gme/gme_types.h b/game-music-emu/gme/gme_types.h
old mode 100644
new mode 100755
index 06226f4aa..bd3670e64
--- a/game-music-emu/gme/gme_types.h
+++ b/game-music-emu/gme/gme_types.h
@@ -1,11 +1,13 @@
 #ifndef GME_TYPES_H
 #define GME_TYPES_H
 
-/*
- * This is a default gme_types.h for use when *not* using
- * CMake.  If CMake is in use gme_types.h.in will be
- * processed instead.
+/* CMake will either define the following to 1, or #undef it,
+ * depending on the options passed to CMake.  This is used to
+ * conditionally compile in the various emulator types.
+ *
+ * See gme_type_list() in gme.cpp
  */
+
 #define USE_GME_AY
 #define USE_GME_GBS
 #define USE_GME_GYM
diff --git a/src/actor.h b/src/actor.h
index 03891c8ba..5445c92be 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -33,6 +33,7 @@
 // States are tied to finite states are tied to animation frames.
 #include "info.h"
 
+#include <forward_list>
 #include "doomdef.h"
 #include "textures/textures.h"
 #include "r_data/renderstyle.h"
@@ -561,8 +562,15 @@ inline T *GetDefault ()
 
 struct line_t;
 struct secplane_t;
+struct msecnode_t;
 struct FStrifeDialogueNode;
 
+struct FLinkContext
+{
+	msecnode_t *sector_list = nullptr;
+	msecnode_t *render_list = nullptr;
+};
+
 class DDropItem : public DObject
 {
 	DECLARE_CLASS(DDropItem, DObject)
@@ -1035,6 +1043,7 @@ public:
 	struct sector_t	*ceilingsector;
 	FTextureID		ceilingpic;			// contacted sec ceilingpic
 	double			radius, Height;		// for movement checking
+	double			renderradius;
 
 	double			projectilepassheight;	// height for clipping projectile movement against this actor
 	
@@ -1141,6 +1150,8 @@ public:
 	struct msecnode_t	*touching_sectorlist;				// phares 3/14/98
 	struct msecnode_t	*render_sectorlist;		// same for cross-sectorportal rendering
 	struct portnode_t	*render_portallist;		// and for cross-lineportal
+	struct msecnode_t	*touching_rendersectors; // this is the list of sectors that this thing interesects with it's max(radius, renderradius).
+	int validcount;
 
 
 	TObjPtr<AInventory>	Inventory;		// [RH] This actor's inventory
@@ -1216,8 +1227,8 @@ private:
 	bool FixMapthingPos();
 
 public:
-	void LinkToWorld (bool spawningmapthing=false, sector_t *sector = NULL);
-	void UnlinkFromWorld ();
+	void LinkToWorld (FLinkContext *ctx, bool spawningmapthing=false, sector_t *sector = NULL);
+	void UnlinkFromWorld(FLinkContext *ctx);
 	void AdjustFloorClip ();
 	bool InStateSequence(FState * newstate, FState * basestate);
 	int GetTics(FState * newstate);
diff --git a/src/b_game.cpp b/src/b_game.cpp
index 9d6419787..b99b97a60 100644
--- a/src/b_game.cpp
+++ b/src/b_game.cpp
@@ -118,23 +118,24 @@ void FCajunMaster::Main ()
 	}
 
 	//Check if player should go observer. Or un observe
+	FLinkContext ctx;
 	if (bot_observer && !observer && !netgame)
 	{
 		Printf ("%s is now observer\n", players[consoleplayer].userinfo.GetName());
 		observer = true;
-		players[consoleplayer].mo->UnlinkFromWorld ();
+		players[consoleplayer].mo->UnlinkFromWorld (&ctx);
 		players[consoleplayer].mo->flags = MF_DROPOFF|MF_NOBLOCKMAP|MF_NOCLIP|MF_NOTDMATCH|MF_NOGRAVITY|MF_FRIENDLY;
 		players[consoleplayer].mo->flags2 |= MF2_FLY;
-		players[consoleplayer].mo->LinkToWorld ();
+		players[consoleplayer].mo->LinkToWorld (&ctx);
 	}
 	else if (!bot_observer && observer && !netgame) //Go back
 	{
 		Printf ("%s returned to the fray\n", players[consoleplayer].userinfo.GetName());
 		observer = false;
-		players[consoleplayer].mo->UnlinkFromWorld ();
+		players[consoleplayer].mo->UnlinkFromWorld (&ctx);
 		players[consoleplayer].mo->flags = MF_SOLID|MF_SHOOTABLE|MF_DROPOFF|MF_PICKUP|MF_NOTDMATCH|MF_FRIENDLY;
 		players[consoleplayer].mo->flags2 &= ~MF2_FLY;
-		players[consoleplayer].mo->LinkToWorld ();
+		players[consoleplayer].mo->LinkToWorld (&ctx);
 	}
 }
 
diff --git a/src/g_inventory/a_pickups.cpp b/src/g_inventory/a_pickups.cpp
index 42af5e87f..f019a8053 100644
--- a/src/g_inventory/a_pickups.cpp
+++ b/src/g_inventory/a_pickups.cpp
@@ -636,14 +636,9 @@ void AInventory::BecomeItem ()
 {
 	if (!(flags & (MF_NOBLOCKMAP|MF_NOSECTOR)))
 	{
-		UnlinkFromWorld ();
-		if (sector_list)
-		{
-			P_DelSeclist (sector_list);
-			sector_list = NULL;
-		}
+		UnlinkFromWorld (nullptr);
 		flags |= MF_NOBLOCKMAP|MF_NOSECTOR;
-		LinkToWorld ();
+		LinkToWorld (nullptr);
 	}
 	RemoveFromHash ();
 	flags &= ~MF_SPECIAL;
@@ -674,9 +669,9 @@ void AInventory::BecomePickup ()
 	}
 	if (flags & (MF_NOBLOCKMAP|MF_NOSECTOR))
 	{
-		UnlinkFromWorld ();
+		UnlinkFromWorld (nullptr);
 		flags &= ~(MF_NOBLOCKMAP|MF_NOSECTOR);
-		LinkToWorld ();
+		LinkToWorld (nullptr);
 		P_FindFloorCeiling (this);
 	}
 	flags = (GetDefault()->flags | MF_DROPPED) & ~MF_COUNTITEM;
diff --git a/src/g_level.cpp b/src/g_level.cpp
index c13e71ee6..f8ccd13be 100644
--- a/src/g_level.cpp
+++ b/src/g_level.cpp
@@ -1196,8 +1196,7 @@ void G_StartTravel ()
 			// Only living players travel. Dead ones get a new body on the new level.
 			if (players[i].health > 0)
 			{
-				pawn->UnlinkFromWorld ();
-				P_DelSector_List ();
+				pawn->UnlinkFromWorld (nullptr);
 				int tid = pawn->tid;	// Save TID
 				pawn->RemoveFromHash ();
 				pawn->tid = tid;		// Restore TID (but no longer linked into the hash chain)
@@ -1206,8 +1205,7 @@ void G_StartTravel ()
 				for (inv = pawn->Inventory; inv != NULL; inv = inv->Inventory)
 				{
 					inv->ChangeStatNum (STAT_TRAVELLING);
-					inv->UnlinkFromWorld ();
-					P_DelSector_List ();
+					inv->UnlinkFromWorld (nullptr);
 				}
 			}
 		}
@@ -1304,7 +1302,7 @@ void G_FinishTravel ()
 		{
 			pawndup->Destroy();
 		}
-		pawn->LinkToWorld ();
+		pawn->LinkToWorld (nullptr);
 		pawn->ClearInterpolation();
 		pawn->AddToHash ();
 		pawn->SetState(pawn->SpawnState);
@@ -1313,7 +1311,7 @@ void G_FinishTravel ()
 		for (inv = pawn->Inventory; inv != NULL; inv = inv->Inventory)
 		{
 			inv->ChangeStatNum (STAT_INVENTORY);
-			inv->LinkToWorld ();
+			inv->LinkToWorld (nullptr);
 			inv->Travelled ();
 		}
 		if (ib_compatflags & BCOMPATF_RESETPLAYERSPEED)
diff --git a/src/g_pch.h b/src/g_pch.h
index a22649815..2c3676f5a 100644
--- a/src/g_pch.h
+++ b/src/g_pch.h
@@ -12,6 +12,7 @@
 #include <zlib.h>
 #include <new>
 #include <algorithm>
+#include <forward_list>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <cassert>
diff --git a/src/g_shared/a_movingcamera.cpp b/src/g_shared/a_movingcamera.cpp
index a1ffe5dc6..c09d93fd5 100644
--- a/src/g_shared/a_movingcamera.cpp
+++ b/src/g_shared/a_movingcamera.cpp
@@ -364,6 +364,7 @@ void APathFollower::NewNode ()
 bool APathFollower::Interpolate ()
 {
 	DVector3 dpos(0, 0, 0);
+	FLinkContext ctx;
 
 	if ((args[2] & 8) && Time > 0.f)
 	{
@@ -372,7 +373,7 @@ bool APathFollower::Interpolate ()
 
 	if (CurrNode->Next==NULL) return false;
 
-	UnlinkFromWorld ();
+	UnlinkFromWorld (&ctx);
 	DVector3 newpos;
 	if (args[2] & 1)
 	{	// linear
@@ -389,7 +390,7 @@ bool APathFollower::Interpolate ()
 		newpos.Z = Splerp(PrevNode->Z(), CurrNode->Z(), CurrNode->Next->Z(), CurrNode->Next->Next->Z());
 	}
 	SetXYZ(newpos);
-	LinkToWorld ();
+	LinkToWorld (&ctx);
 
 	if (args[2] & 6)
 	{
@@ -541,10 +542,11 @@ void AActorMover::Activate (AActor *activator)
 	tracer->flags |= MF_NOGRAVITY;
 	if (args[2] & 128)
 	{
-		tracer->UnlinkFromWorld ();
+		FLinkContext ctx;
+		tracer->UnlinkFromWorld (&ctx);
 		tracer->flags |= MF_NOBLOCKMAP;
 		tracer->flags &= ~MF_SOLID;
-		tracer->LinkToWorld ();
+		tracer->LinkToWorld (&ctx);
 	}
 	if (tracer->flags3 & MF3_ISMONSTER)
 	{
@@ -563,9 +565,10 @@ void AActorMover::Deactivate (AActor *activator)
 		Super::Deactivate (activator);
 		if (tracer != NULL)
 		{
-			tracer->UnlinkFromWorld ();
+			FLinkContext ctx;
+			tracer->UnlinkFromWorld (&ctx);
 			tracer->flags = ActorFlags::FromInt (special1);
-			tracer->LinkToWorld ();
+			tracer->LinkToWorld (&ctx);
 			tracer->flags2 = ActorFlags2::FromInt (special2);
 		}
 	}
diff --git a/src/p_actionfunctions.cpp b/src/p_actionfunctions.cpp
index e292447bf..4136ec331 100644
--- a/src/p_actionfunctions.cpp
+++ b/src/p_actionfunctions.cpp
@@ -5229,12 +5229,13 @@ void A_Weave(AActor *self, int xyspeed, int zspeed, double xydist, double zdist)
 		}
 		else
 		{
-			self->UnlinkFromWorld ();
+			FLinkContext ctx;
+			self->UnlinkFromWorld (&ctx);
 			self->flags |= MF_NOBLOCKMAP;
 			// We need to do portal offsetting here explicitly, because SetXY cannot do that.
 			newpos -= self->Pos().XY();
 			self->SetXY(self->Vec2Offset(newpos.X, newpos.Y));
-			self->LinkToWorld ();
+			self->LinkToWorld (&ctx);
 		}
 		self->WeaveIndexXY = weaveXY;
 	}
@@ -6862,17 +6863,18 @@ DEFINE_ACTION_FUNCTION(AActor, A_SetSize)
 	double oldradius = self->radius;
 	double oldheight = self->Height;
 
-	self->UnlinkFromWorld();
+	FLinkContext ctx;
+	self->UnlinkFromWorld(&ctx);
 	self->radius = newradius;
 	self->Height = newheight;
-	self->LinkToWorld();
+	self->LinkToWorld(&ctx);
 
 	if (testpos && !P_TestMobjLocation(self))
 	{
-		self->UnlinkFromWorld();
+		self->UnlinkFromWorld(&ctx);
 		self->radius = oldradius;
 		self->Height = oldheight;
-		self->LinkToWorld();
+		self->LinkToWorld(&ctx);
 		ACTION_RETURN_BOOL(false);
 	}
 
diff --git a/src/p_local.h b/src/p_local.h
index ef702e018..93bbbbf11 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -245,10 +245,6 @@ AActor *P_RoughMonsterSearch (AActor *mo, int distance, bool onlyseekable=false,
 //
 
 
-// If "floatok" true, move would be ok
-// if within "tmfloorz - tmceilingz".
-extern msecnode_t		*sector_list;		// phares 3/16/98
-
 struct spechit_t
 {
 	line_t *line;
@@ -395,11 +391,10 @@ enum
 int	P_RadiusAttack (AActor *spot, AActor *source, int damage, int distance, 
 						FName damageType, int flags, int fulldamagedistance=0);
 
-void	P_DelSector_List();
-void	P_DelSeclist(msecnode_t *);							// phares 3/16/98
+void	P_DelSeclist(msecnode_t *, msecnode_t *sector_t::*seclisthead);
 msecnode_t *P_AddSecnode(sector_t *s, AActor *thing, msecnode_t *nextnode, msecnode_t *&sec_thinglist);
 msecnode_t*	P_DelSecnode(msecnode_t *, msecnode_t *sector_t::*head);
-void	P_CreateSecNodeList(AActor*);		// phares 3/14/98
+msecnode_t *P_CreateSecNodeList(AActor *thing, double radius, msecnode_t *sector_list, msecnode_t *sector_t::*seclisthead);
 double	P_GetMoveFactor(const AActor *mo, double *frictionp);	// phares  3/6/98
 double		P_GetFriction(const AActor *mo, double *frictionfactor);
 
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 81934ceb7..85c3e3da8 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -24,6 +24,7 @@
 
 #include <stdlib.h>
 #include <math.h>
+#include <algorithm>
 
 #include "templates.h"
 
@@ -81,9 +82,6 @@ static FRandom pr_crunch("DoCrunch");
 TArray<spechit_t> spechit;
 TArray<spechit_t> portalhit;
 
-// Temporary holder for thing_sectorlist threads
-msecnode_t* sector_list = NULL;		// phares 3/16/98
-
 //==========================================================================
 //
 // FindRefPoint
@@ -2389,10 +2387,11 @@ bool P_TryMove(AActor *thing, const DVector2 &pos,
 			FLinePortal *port = ld->getPortal();
 			if (port->mType == PORTT_LINKED)
 			{
-				thing->UnlinkFromWorld();
+				FLinkContext ctx;
+				thing->UnlinkFromWorld(&ctx);
 				thing->SetXY(tm.pos + port->mDisplacement);
 				thing->Prev += port->mDisplacement;
-				thing->LinkToWorld();
+				thing->LinkToWorld(&ctx);
 				P_FindFloorCeiling(thing);
 				portalcrossed = true;
 				tm.portalstep = false;
@@ -2413,11 +2412,12 @@ bool P_TryMove(AActor *thing, const DVector2 &pos,
 					thing->flags6 &= ~MF6_INTRYMOVE;
 					return false;
 				}
-				thing->UnlinkFromWorld();
+				FLinkContext ctx;
+				thing->UnlinkFromWorld(&ctx);
 				thing->SetXYZ(pos);
 				P_TranslatePortalVXVY(ld, thing->Vel.X, thing->Vel.Y);
 				P_TranslatePortalAngle(ld, thing->Angles.Yaw);
-				thing->LinkToWorld();
+				thing->LinkToWorld(&ctx);
 				P_FindFloorCeiling(thing);
 				thing->ClearInterpolation();
 				portalcrossed = true;
@@ -2458,7 +2458,8 @@ bool P_TryMove(AActor *thing, const DVector2 &pos,
 	if (!portalcrossed)
 	{
 		// the move is ok, so link the thing into its new position
-		thing->UnlinkFromWorld();
+		FLinkContext ctx;
+		thing->UnlinkFromWorld(&ctx);
 
 		oldsector = thing->Sector;
 		thing->floorz = tm.floorz;
@@ -2471,7 +2472,7 @@ bool P_TryMove(AActor *thing, const DVector2 &pos,
 		thing->ceilingsector = tm.ceilingsector;
 		thing->SetXY(pos);
 
-		thing->LinkToWorld();
+		thing->LinkToWorld(&ctx);
 	}
 
 	if (thing->flags2 & MF2_FLOORCLIP)
@@ -2564,13 +2565,14 @@ bool P_TryMove(AActor *thing, const DVector2 &pos,
 	// If the actor stepped through a ceiling portal we need to reacquire the actual position info after the transition
 	if (tm.portalstep)
 	{
+		FLinkContext ctx;
 		DVector3 oldpos = thing->Pos();
-		thing->UnlinkFromWorld();
+		thing->UnlinkFromWorld(&ctx);
 		thing->SetXYZ(thing->PosRelative(thing->Sector->GetOppositePortalGroup(sector_t::ceiling)));
 		thing->Prev = thing->Pos() - oldpos;
 		thing->Sector = P_PointInSector(thing->Pos());
 		thing->PrevPortalGroup = thing->Sector->PortalGroup;
-		thing->LinkToWorld();
+		thing->LinkToWorld(&ctx);
 
 		P_FindFloorCeiling(thing);
 	}
@@ -6531,23 +6533,6 @@ msecnode_t *P_DelSecnode(msecnode_t *node, msecnode_t *sector_t::*listhead)
 	return NULL;
 } 														// phares 3/13/98
 
-//=============================================================================
-//
-// P_DelSector_List
-//
-// Deletes the sector_list and NULLs it.
-//
-//=============================================================================
-
-void P_DelSector_List()
-{
-	if (sector_list != NULL)
-	{
-		P_DelSeclist(sector_list);
-		sector_list = NULL;
-	}
-}
-
 //=============================================================================
 //
 // P_DelSeclist
@@ -6556,10 +6541,10 @@ void P_DelSector_List()
 //
 //=============================================================================
 
-void P_DelSeclist(msecnode_t *node)
+void P_DelSeclist(msecnode_t *node, msecnode_t *sector_t::*sechead)
 {
 	while (node)
-		node = P_DelSecnode(node, &sector_t::touching_thinglist);
+		node = P_DelSecnode(node, sechead);
 }
 
 //=============================================================================
@@ -6571,7 +6556,7 @@ void P_DelSeclist(msecnode_t *node)
 //
 //=============================================================================
 
-void P_CreateSecNodeList(AActor *thing)
+msecnode_t *P_CreateSecNodeList(AActor *thing, double radius, msecnode_t *sector_list, msecnode_t *sector_t::*seclisthead)
 {
 	msecnode_t *node;
 
@@ -6587,7 +6572,7 @@ void P_CreateSecNodeList(AActor *thing)
 		node = node->m_tnext;
 	}
 
-	FBoundingBox box(thing->X(), thing->Y(), thing->radius);
+	FBoundingBox box(thing->X(), thing->Y(), radius);
 	FBlockLinesIterator it(box);
 	line_t *ld;
 
@@ -6603,7 +6588,7 @@ void P_CreateSecNodeList(AActor *thing)
 		// allowed to move to this position, then the sector_list
 		// will be attached to the Thing's AActor at touching_sectorlist.
 
-		sector_list = P_AddSecnode(ld->frontsector, thing, sector_list, ld->frontsector->touching_thinglist);
+		sector_list = P_AddSecnode(ld->frontsector, thing, sector_list, ld->frontsector->*seclisthead);
 
 		// Don't assume all lines are 2-sided, since some Things
 		// like MT_TFOG are allowed regardless of whether their radius takes
@@ -6613,12 +6598,12 @@ void P_CreateSecNodeList(AActor *thing)
 		// Use sidedefs instead of 2s flag to determine two-sidedness.
 
 		if (ld->backsector)
-			sector_list = P_AddSecnode(ld->backsector, thing, sector_list, ld->backsector->touching_thinglist);
+			sector_list = P_AddSecnode(ld->backsector, thing, sector_list, ld->backsector->*seclisthead);
 	}
 
 	// Add the sector of the (x,y) point to sector_list.
 
-	sector_list = P_AddSecnode(thing->Sector, thing, sector_list, thing->Sector->touching_thinglist);
+	sector_list = P_AddSecnode(thing->Sector, thing, sector_list, thing->Sector->*seclisthead);
 
 	// Now delete any nodes that won't be used. These are the ones where
 	// m_thing is still NULL.
@@ -6630,16 +6615,16 @@ void P_CreateSecNodeList(AActor *thing)
 		{
 			if (node == sector_list)
 				sector_list = node->m_tnext;
-			node = P_DelSecnode(node, &sector_t::touching_thinglist);
+			node = P_DelSecnode(node, seclisthead);
 		}
 		else
 		{
 			node = node->m_tnext;
 		}
 	}
+	return sector_list;
 }
 
-
 //=============================================================================
 //
 // P_DelPortalnode
@@ -6770,6 +6755,7 @@ void AActor::UpdateRenderSectorList()
 			sec = P_PointInSector(newpos);
 			render_sectorlist = P_AddSecnode(sec, this, render_sectorlist, sec->render_thinglist);
 		}
+		sec = Sector;
 		lasth = FLT_MAX;
 		while (!sec->PortalBlocksMovement(sector_t::floor))
 		{
diff --git a/src/p_maputl.cpp b/src/p_maputl.cpp
index d676e966c..d4ac79ce7 100644
--- a/src/p_maputl.cpp
+++ b/src/p_maputl.cpp
@@ -242,9 +242,9 @@ void P_LineOpening (FLineOpening &open, AActor *actor, const line_t *linedef, co
 //
 //==========================================================================
 
-void AActor::UnlinkFromWorld ()
+void AActor::UnlinkFromWorld (FLinkContext *ctx)
 {
-	sector_list = NULL;
+	if (ctx != nullptr) ctx->sector_list = nullptr;
 	if (!(flags & MF_NOSECTOR))
 	{
 		// invisible things don't need to be in sector list
@@ -271,12 +271,19 @@ void AActor::UnlinkFromWorld ()
 			// put it back into touching_sectorlist. It's done this way to
 			// avoid a lot of deleting/creating for nodes, when most of the
 			// time you just get back what you deleted anyway.
-			//
-			// If this Thing is being removed entirely, then the calling
-			// routine will clear out the nodes in sector_list.
 
-			sector_list = touching_sectorlist;
-			touching_sectorlist = NULL; //to be restored by P_SetThingPosition
+			if (ctx != nullptr)
+			{
+				ctx->sector_list = touching_sectorlist;
+				ctx->render_list = touching_rendersectors;
+			}
+			else
+			{
+				P_DelSeclist(touching_sectorlist, &sector_t::touching_thinglist);
+				P_DelSeclist(touching_rendersectors, &sector_t::touching_renderthings);
+			}
+			touching_sectorlist = nullptr; //to be restored by P_SetThingPosition
+			touching_rendersectors = nullptr;
 		}
 	}
 		
@@ -388,7 +395,7 @@ bool AActor::FixMapthingPos()
 DEFINE_ACTION_FUNCTION(AActor, UnlinkFromWorld)
 {
 	PARAM_SELF_PROLOGUE(AActor);
-	self->UnlinkFromWorld();
+	self->UnlinkFromWorld(nullptr); // fixme
 	return 0;
 }
 
@@ -401,7 +408,7 @@ DEFINE_ACTION_FUNCTION(AActor, UnlinkFromWorld)
 //
 //==========================================================================
 
-void AActor::LinkToWorld(bool spawningmapthing, sector_t *sector)
+void AActor::LinkToWorld(FLinkContext *ctx, bool spawningmapthing, sector_t *sector)
 {
 	bool spawning = spawningmapthing;
 
@@ -453,9 +460,13 @@ void AActor::LinkToWorld(bool spawningmapthing, sector_t *sector)
 		// When a node is deleted, its sector links (the links starting
 		// at sector_t->touching_thinglist) are broken. When a node is
 		// added, new sector links are created.
-		P_CreateSecNodeList(this);
-		touching_sectorlist = sector_list;	// Attach to thing
-		sector_list = NULL;		// clear for next time
+		touching_sectorlist = P_CreateSecNodeList(this, radius, ctx != nullptr? ctx->sector_list : nullptr, &sector_t::touching_thinglist);	// Attach to thing
+		if (renderradius >= 0) touching_rendersectors = P_CreateSecNodeList(this, MAX(radius, renderradius), ctx != nullptr ? ctx->render_list : nullptr, &sector_t::touching_renderthings);
+		else
+		{
+			touching_rendersectors = nullptr;
+			if (ctx != nullptr) P_DelSeclist(ctx->render_list, &sector_t::touching_renderthings);
+		}
 	}
 
 
@@ -518,15 +529,16 @@ void AActor::LinkToWorld(bool spawningmapthing, sector_t *sector)
 DEFINE_ACTION_FUNCTION(AActor, LinkToWorld)
 {
 	PARAM_SELF_PROLOGUE(AActor);
-	self->LinkToWorld();
+	self->LinkToWorld(nullptr);	// fixme
 	return 0;
 }
 
 void AActor::SetOrigin(double x, double y, double z, bool moving)
 {
-	UnlinkFromWorld ();
+	FLinkContext ctx;
+	UnlinkFromWorld (&ctx);
 	SetXYZ(x, y, z);
-	LinkToWorld ();
+	LinkToWorld (&ctx);
 	P_FindFloorCeiling(this, FFCF_ONLYSPAWNPOS);
 	if (!moving) ClearInterpolation();
 }
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 72ddd9395..7e5dbc88e 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -204,6 +204,7 @@ DEFINE_FIELD(AActor, ceilingsector)
 DEFINE_FIELD(AActor, ceilingpic)
 DEFINE_FIELD(AActor, Height)
 DEFINE_FIELD(AActor, radius)
+DEFINE_FIELD(AActor, renderradius)
 DEFINE_FIELD(AActor, projectilepassheight)
 DEFINE_FIELD(AActor, tics)
 DEFINE_FIELD_NAMED(AActor, state, curstate)		// clashes with type 'state'.
@@ -373,6 +374,7 @@ void AActor::Serialize(FSerializer &arc)
 		A("floorsector", floorsector)
 		A("ceilingsector", ceilingsector)
 		A("radius", radius)
+		A("renderradius", renderradius)
 		A("height", Height)
 		A("ppassheight", projectilepassheight)
 		A("vel", Vel)
@@ -509,8 +511,9 @@ void AActor::Serialize(FSerializer &arc)
 
 void AActor::PostSerialize()
 {
-	touching_sectorlist = NULL;
-	LinkToWorld(false, Sector);
+	touching_sectorlist = nullptr;
+	touching_rendersectors = nullptr;
+	LinkToWorld(nullptr, false, Sector);
 
 	AddToHash();
 	if (player)
@@ -3686,12 +3689,13 @@ DVector3 AActor::GetPortalTransition(double byoffset, sector_t **pSec)
 void AActor::CheckPortalTransition(bool islinked)
 {
 	bool moved = false;
+	FLinkContext ctx;
 	while (!Sector->PortalBlocksMovement(sector_t::ceiling))
 	{
 		if (Z() >= Sector->GetPortalPlaneZ(sector_t::ceiling))
 		{
 			DVector3 oldpos = Pos();
-			if (islinked && !moved) UnlinkFromWorld();
+			if (islinked && !moved) UnlinkFromWorld(&ctx);
 			SetXYZ(PosRelative(Sector->GetOppositePortalGroup(sector_t::ceiling)));
 			Prev = Pos() - oldpos;
 			Sector = P_PointInSector(Pos());
@@ -3708,7 +3712,7 @@ void AActor::CheckPortalTransition(bool islinked)
 			if (Z() < portalz && floorz < portalz)
 			{
 				DVector3 oldpos = Pos();
-				if (islinked && !moved) UnlinkFromWorld();
+				if (islinked && !moved) UnlinkFromWorld(&ctx);
 				SetXYZ(PosRelative(Sector->GetOppositePortalGroup(sector_t::floor)));
 				Prev = Pos() - oldpos;
 				Sector = P_PointInSector(Pos());
@@ -3718,7 +3722,7 @@ void AActor::CheckPortalTransition(bool islinked)
 			else break;
 		}
 	}
-	if (islinked && moved) LinkToWorld();
+	if (islinked && moved) LinkToWorld(&ctx);
 }
 
 //
@@ -3781,11 +3785,12 @@ void AActor::Tick ()
 
 		if (!Vel.isZero() || !(flags & MF_NOBLOCKMAP))
 		{
-			UnlinkFromWorld();
+			FLinkContext ctx;
+			UnlinkFromWorld(&ctx);
 			flags |= MF_NOBLOCKMAP;
 			SetXYZ(Vec3Offset(Vel));
 			CheckPortalTransition(false);
-			LinkToWorld();
+			LinkToWorld(&ctx);
 		}
 	}
 	else
@@ -4543,12 +4548,13 @@ AActor *AActor::StaticSpawn (PClassActor *type, const DVector3 &pos, replace_t a
 	actor->sprite = st->sprite;
 	actor->frame = st->GetFrame();
 	actor->renderflags = (actor->renderflags & ~RF_FULLBRIGHT) | ActorRenderFlags::FromInt (st->GetFullbright());
-	actor->touching_sectorlist = NULL;	// NULL head of sector list // phares 3/13/98
+	actor->touching_sectorlist = nullptr;	// NULL head of sector list // phares 3/13/98
+	actor->touching_rendersectors = nullptr;
 	if (G_SkillProperty(SKILLP_FastMonsters) && actor->GetClass()->FastSpeed >= 0)
 	actor->Speed = actor->GetClass()->FastSpeed;
 
 	// set subsector and/or block links
-	actor->LinkToWorld (SpawningMapThing);
+	actor->LinkToWorld (nullptr, SpawningMapThing);
 	actor->ClearInterpolation();
 
 	actor->dropoffz = actor->floorz = actor->Sector->floorplane.ZatPoint(pos);
@@ -4925,12 +4931,9 @@ void AActor::Destroy ()
 	RemoveFromHash ();
 
 	// unlink from sector and block lists
-	UnlinkFromWorld ();
+	UnlinkFromWorld (nullptr);
 	flags |= MF_NOSECTOR|MF_NOBLOCKMAP;
 
-	// Delete all nodes on the current sector_list			phares 3/16/98
-	P_DelSector_List();
-
 	// Transform any playing sound into positioned, non-actor sounds.
 	S_RelinkSound (this, NULL);
 
@@ -7481,9 +7484,10 @@ void AActor::RestoreSpecialPosition()
 	// Move item back to its original location
 	DVector2 sp = SpawnPoint;
 
-	UnlinkFromWorld();
+	FLinkContext ctx;
+	UnlinkFromWorld(&ctx);
 	SetXY(sp);
-	LinkToWorld(true);
+	LinkToWorld(&ctx, true);
 	SetZ(Sector->floorplane.ZatPoint(sp));
 	P_FindFloorCeiling(this, FFCF_ONLYSPAWNPOS | FFCF_NOPORTALS);	// no portal checks here so that things get spawned in this sector.
 
diff --git a/src/p_setup.cpp b/src/p_setup.cpp
index 11aef9d8d..d3bcc742d 100644
--- a/src/p_setup.cpp
+++ b/src/p_setup.cpp
@@ -1509,9 +1509,10 @@ void P_LoadSectors (MapData *map, FMissingTextureTracker &missingtex)
 		else	// [RH] Translate to new sector special
 			ss->special = P_TranslateSectorSpecial (LittleShort(ms->special));
 		tagManager.AddSectorTag(i, LittleShort(ms->tag));
-		ss->thinglist = NULL;
-		ss->touching_thinglist = NULL;		// phares 3/14/98
-		ss->render_thinglist = NULL;
+		ss->thinglist = nullptr;
+		ss->touching_thinglist = nullptr;		// phares 3/14/98
+		ss->render_thinglist = nullptr;
+		ss->touching_renderthings = nullptr;
 		ss->seqType = defSeqType;
 		ss->SeqName = NAME_None;
 		ss->nextsec = -1;	//jff 2/26/98 add fields to support locking out
diff --git a/src/p_udmf.cpp b/src/p_udmf.cpp
index c1a64f84b..2ef8a9ced 100644
--- a/src/p_udmf.cpp
+++ b/src/p_udmf.cpp
@@ -1294,9 +1294,10 @@ public:
 		sec->SetYScale(sector_t::ceiling, 1.);
 		sec->SetAlpha(sector_t::floor, 1.);
 		sec->SetAlpha(sector_t::ceiling, 1.);
-		sec->thinglist = NULL;
-		sec->touching_thinglist = NULL;		// phares 3/14/98
-		sec->render_thinglist = NULL;
+		sec->thinglist = nullptr;
+		sec->touching_thinglist = nullptr;		// phares 3/14/98
+		sec->render_thinglist = nullptr;
+		sec->touching_renderthings = nullptr;
 		sec->seqType = (level.flags & LEVEL_SNDSEQTOTALCTRL) ? 0 : -1;
 		sec->nextsec = -1;	//jff 2/26/98 add fields to support locking out
 		sec->prevsec = -1;	// stair retriggering until build completes
diff --git a/src/p_user.cpp b/src/p_user.cpp
index 28047b4e2..c8f30e0d7 100644
--- a/src/p_user.cpp
+++ b/src/p_user.cpp
@@ -2940,7 +2940,8 @@ void P_UnPredictPlayer ()
 		// could cause it to change during prediction.
 		player->camera = savedcamera;
 
-		act->UnlinkFromWorld();
+		FLinkContext ctx;
+		act->UnlinkFromWorld(&ctx);
 		memcpy(&act->snext, PredictionActorBackup, sizeof(APlayerPawn) - ((BYTE *)&act->snext - (BYTE *)act));
 
 		// The blockmap ordering needs to remain unchanged, too.
@@ -2969,7 +2970,7 @@ void P_UnPredictPlayer ()
 			}
 
 			// Destroy old refrences
-			msecnode_t *node = sector_list;
+			msecnode_t *node = ctx.sector_list;
 			while (node)
 			{
 				node->m_thing = NULL;
@@ -2977,22 +2978,23 @@ void P_UnPredictPlayer ()
 			}
 
 			// Make the sector_list match the player's touching_sectorlist before it got predicted.
-			P_DelSeclist(sector_list);
-			sector_list = NULL;
+			P_DelSeclist(ctx.sector_list, &sector_t::touching_thinglist);
+			ctx.sector_list = NULL;
 			for (i = PredictionTouchingSectorsBackup.Size(); i-- > 0;)
 			{
-				sector_list = P_AddSecnode(PredictionTouchingSectorsBackup[i], act, sector_list, PredictionTouchingSectorsBackup[i]->touching_thinglist);
+				ctx.sector_list = P_AddSecnode(PredictionTouchingSectorsBackup[i], act, ctx.sector_list, PredictionTouchingSectorsBackup[i]->touching_thinglist);
 			}
-			act->touching_sectorlist = sector_list;	// Attach to thing
-			sector_list = NULL;		// clear for next time
+			act->touching_sectorlist = ctx.sector_list;	// Attach to thing
+			ctx.sector_list = NULL;		// clear for next time
 
-			node = sector_list;
+			// Huh???
+			node = ctx.sector_list;
 			while (node)
 			{
 				if (node->m_thing == NULL)
 				{
-					if (node == sector_list)
-						sector_list = node->m_tnext;
+					if (node == ctx.sector_list)
+						ctx.sector_list = node->m_tnext;
 					node = P_DelSecnode(node, &sector_t::touching_thinglist);
 				}
 				else
diff --git a/src/portal.cpp b/src/portal.cpp
index 156643cfb..121b05e19 100644
--- a/src/portal.cpp
+++ b/src/portal.cpp
@@ -1140,8 +1140,9 @@ void P_CreateLinkedPortals()
 				P_CollectConnectedGroups(actor->Sector->PortalGroup, actor->Pos(), actor->Top(), actor->radius, check);
 				if (check.Size() > 0)
 				{
-					actor->UnlinkFromWorld();
-					actor->LinkToWorld();
+					FLinkContext ctx;
+					actor->UnlinkFromWorld(&ctx);
+					actor->LinkToWorld(&ctx);
 				}
 			}
 		}
diff --git a/src/r_defs.h b/src/r_defs.h
index ca29bb632..36318be85 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -23,6 +23,7 @@
 #ifndef __R_DEFS_H__
 #define __R_DEFS_H__
 
+#include <forward_list>
 #include "doomdef.h"
 #include "templates.h"
 #include "memarena.h"
@@ -1048,6 +1049,7 @@ public:
 	// thinglist is a subset of touching_thinglist
 	struct msecnode_t *touching_thinglist;				// phares 3/14/98
 	struct msecnode_t *render_thinglist;				// for cross-portal rendering.
+	struct msecnode_t *touching_renderthings; // this is used to allow wide things to be rendered not only from their main sector.
 
 	double gravity;			// [RH] Sector gravity (1.0 is normal)
 	FNameNoInit damagetype;		// [RH] Means-of-death for applied damage
diff --git a/src/r_things.cpp b/src/r_things.cpp
index 472ecc8ea..40fbf782a 100644
--- a/src/r_things.cpp
+++ b/src/r_things.cpp
@@ -769,7 +769,7 @@ void R_DrawVisVoxel(vissprite_t *spr, int minslabz, int maxslabz, short *cliptop
 // R_ProjectSprite
 // Generates a vissprite for a thing if it might be visible.
 //
-void R_ProjectSprite (AActor *thing, int fakeside, F3DFloor *fakefloor, F3DFloor *fakeceiling)
+void R_ProjectSprite (AActor *thing, int fakeside, F3DFloor *fakefloor, F3DFloor *fakeceiling, sector_t *current_sector)
 {
 	double 			tr_x;
 	double 			tr_y;
@@ -1141,6 +1141,10 @@ void R_ProjectSprite (AActor *thing, int fakeside, F3DFloor *fakefloor, F3DFloor
 	}
 
 	FDynamicColormap *mybasecolormap = basecolormap;
+	if (current_sector->sectornum != thing->Sector->sectornum)	// compare sectornums to account for R_FakeFlat copies.
+	{
+		// Todo: The actor is from a different sector so we have to retrieve the proper basecolormap for that sector.
+	}
 
 	// Sprites that are added to the scene must fade to black.
 	if (vis->Style.RenderStyle == LegacyRenderStyles[STYLE_Add] && mybasecolormap->Fade != 0)
@@ -1274,7 +1278,6 @@ static void R_ProjectWallSprite(AActor *thing, const DVector3 &pos, FTextureID p
 // [RH] Save which side of heightsec sprite is on here.
 void R_AddSprites (sector_t *sec, int lightlevel, int fakeside)
 {
-	AActor *thing;
 	F3DFloor *fakeceiling = NULL;
 	F3DFloor *fakefloor = NULL;
 
@@ -1282,7 +1285,7 @@ void R_AddSprites (sector_t *sec, int lightlevel, int fakeside)
 	// A sector might have been split into several
 	//	subsectors during BSP building.
 	// Thus we check whether it was already added.
-	if (sec->thinglist == NULL || sec->validcount == validcount)
+	if (sec->touching_renderthings == nullptr || sec->validcount == validcount)
 		return;
 
 	// Well, now it will be done.
@@ -1291,8 +1294,12 @@ void R_AddSprites (sector_t *sec, int lightlevel, int fakeside)
 	spriteshade = LIGHT2SHADE(lightlevel + r_actualextralight);
 
 	// Handle all things in sector.
-	for (thing = sec->thinglist; thing; thing = thing->snext)
+	for(auto p = sec->touching_renderthings; p != nullptr; p = p->m_snext)
 	{
+		auto thing = p->m_thing;
+		if (thing->validcount == validcount) continue;
+		thing->validcount = validcount;
+		
 		FIntCVar *cvar = thing->GetClass()->distancecheck;
 		if (cvar != NULL && *cvar >= 0)
 		{
@@ -1305,7 +1312,7 @@ void R_AddSprites (sector_t *sec, int lightlevel, int fakeside)
 		}
 
 		// find fake level
-		for(auto rover : frontsector->e->XFloor.ffloors) 
+		for(auto rover : thing->Sector->e->XFloor.ffloors) 
 		{
 			if(!(rover->flags & FF_EXISTS) || !(rover->flags & FF_RENDERPLANES)) continue;
 			if(!(rover->flags & FF_SOLID) || rover->alpha != 255) continue;
@@ -1321,7 +1328,7 @@ void R_AddSprites (sector_t *sec, int lightlevel, int fakeside)
 				if(rover->bottom.plane->ZatPoint(0., 0.) >= thing->Top()) fakeceiling = rover;
 			}
 		}	
-		R_ProjectSprite (thing, fakeside, fakefloor, fakeceiling);
+		R_ProjectSprite (thing, fakeside, fakefloor, fakeceiling, sec);
 		fakeceiling = NULL;
 		fakefloor = NULL;
 	}
diff --git a/src/scripting/thingdef_properties.cpp b/src/scripting/thingdef_properties.cpp
index e318a9806..27b7ab2d3 100644
--- a/src/scripting/thingdef_properties.cpp
+++ b/src/scripting/thingdef_properties.cpp
@@ -216,9 +216,10 @@ bool ModActorFlag(AActor *actor, FString &flagname, bool set, bool printerror)
 				// If these 2 flags get changed we need to update the blockmap and sector links.
 				bool linkchange = flagp == &actor->flags && (fd->flagbit == MF_NOBLOCKMAP || fd->flagbit == MF_NOSECTOR);
 
-				if (linkchange) actor->UnlinkFromWorld();
+				FLinkContext ctx;
+				if (linkchange) actor->UnlinkFromWorld(&ctx);
 				ModActorFlag(actor, fd, set);
-				if (linkchange) actor->LinkToWorld();
+				if (linkchange) actor->LinkToWorld(&ctx);
 			}
 
 			if (actor->CountsAsKill() && actor->health > 0) ++level.total_monsters;
@@ -713,6 +714,15 @@ DEFINE_PROPERTY(radius, F, Actor)
 	defaults->radius = id;
 }
 
+//==========================================================================
+//
+//==========================================================================
+DEFINE_PROPERTY(renderradius, F, Actor)
+{
+	PROP_DOUBLE_PARM(id, 0);
+	defaults->renderradius = id;
+}
+
 //==========================================================================
 //
 //==========================================================================
diff --git a/wadsrc/static/zscript/actor.txt b/wadsrc/static/zscript/actor.txt
index 4324f162a..2ced709ae 100644
--- a/wadsrc/static/zscript/actor.txt
+++ b/wadsrc/static/zscript/actor.txt
@@ -45,6 +45,7 @@ class Actor : Thinker native
 	native TextureID ceilingpic;
 	native double Height;
 	native readonly double Radius;
+        native readonly double RenderRadius;
 	native double projectilepassheight;
 	native int tics;
 	native readonly State CurState;
@@ -201,6 +202,7 @@ class Actor : Thinker native
 		Health DEFAULT_HEALTH;
 		Reactiontime 8;
 		Radius 20;
+                RenderRadius 0;
 		Height 16;
 		Mass 100;
 		RenderStyle 'Normal';
diff --git a/wadsrc/static/zscript/shared/bridge.txt b/wadsrc/static/zscript/shared/bridge.txt
index ea38796a7..6fb0a99d5 100644
--- a/wadsrc/static/zscript/shared/bridge.txt
+++ b/wadsrc/static/zscript/shared/bridge.txt
@@ -85,6 +85,7 @@ class InvisibleBridge : Actor native
 	{
 		RenderStyle "None";
 		Radius 32;
+		RenderRadius -1;
 		Height 4;
 		+SOLID
 		+NOGRAVITY