diff --git a/src/actor.h b/src/actor.h
index a56d0d6d9..10bbd119a 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -965,6 +965,7 @@ public:
 	void CheckSectorTransition(sector_t *oldsec);
 	void UpdateRenderSectorList();
 	void ClearRenderSectorList();
+	void ClearRenderLineList();
 
 // info for drawing
 // NOTE: The first member variable *must* be snext.
@@ -1101,7 +1102,8 @@ public:
 
 	// a linked list of sectors where this object appears
 	struct msecnode_t	*touching_sectorlist;				// phares 3/14/98
-	struct msecnode_t	*render_sectorlist;		// same for cross-portal rendering
+	struct msecnode_t	*render_sectorlist;		// same for cross-sectorportal rendering
+	struct portnode_t	*render_portallist;		// and for cross-lineportal
 
 
 	TObjPtr<AInventory>	Inventory;		// [RH] This actor's inventory
diff --git a/src/p_map.cpp b/src/p_map.cpp
index c89418a32..72746f2fb 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -44,6 +44,7 @@
 #include "p_trace.h"
 #include "p_checkposition.h"
 #include "r_utility.h"
+#include "p_blockmap.h"
 
 #include "s_sound.h"
 #include "decallib.h"
@@ -6238,6 +6239,91 @@ void P_CreateSecNodeList(AActor *thing)
 }
 
 
+//=============================================================================
+//
+// P_DelPortalnode
+//
+// Same for line portal nodes
+//
+//=============================================================================
+
+portnode_t *P_DelPortalnode(portnode_t *node)
+{
+	portnode_t* tp;  // prev node on thing thread
+	portnode_t* tn;  // next node on thing thread
+	portnode_t* sp;  // prev node on sector thread
+	portnode_t* sn;  // next node on sector thread
+
+	if (node)
+	{
+		// Unlink from the Thing thread. The Thing thread begins at
+		// sector_list and not from AActor->touching_sectorlist.
+
+		tp = node->m_tprev;
+		tn = node->m_tnext;
+		if (tp)
+			tp->m_tnext = tn;
+		if (tn)
+			tn->m_tprev = tp;
+
+		// Unlink from the sector thread. This thread begins at
+		// sector_t->touching_thinglist.
+
+		sp = node->m_sprev;
+		sn = node->m_snext;
+		if (sp)
+			sp->m_snext = sn;
+		else
+			node->m_portal->render_thinglist = sn;
+		if (sn)
+			sn->m_sprev = sp;
+
+		// Return this node to the freelist (use the same one as for msecnodes, since both types are the same size.)
+		P_PutSecnode(reinterpret_cast<msecnode_t *>(node));
+		return tn;
+	}
+	return NULL;
+}
+
+
+//=============================================================================
+//
+// P_AddPortalnode
+//
+//=============================================================================
+
+portnode_t *P_AddPortalnode(FLinePortal *s, AActor *thing, portnode_t *nextnode)
+{
+	portnode_t *node;
+
+	if (s == 0)
+	{
+		I_FatalError("AddSecnode of 0 for %s\n", thing->GetClass()->TypeName.GetChars());
+	}
+
+	node = reinterpret_cast<portnode_t*>(P_GetSecnode());
+
+	// killough 4/4/98, 4/7/98: mark new nodes unvisited.
+	node->visited = 0;
+
+	node->m_portal = s; 			// portal
+	node->m_thing = thing; 			// mobj
+	node->m_tprev = NULL;			// prev node on Thing thread
+	node->m_tnext = nextnode;		// next node on Thing thread
+	if (nextnode)
+		nextnode->m_tprev = node;	// set back link on Thing
+
+									// Add new node at head of portal thread starting at s->touching_thinglist
+
+	node->m_sprev = NULL;			// prev node on portal thread
+	node->m_snext = s->render_thinglist; // next node on portal thread
+	if (s->render_thinglist)
+		node->m_snext->m_sprev = node;
+	s->render_thinglist = node;
+	return node;
+}
+
+
 //==========================================================================
 //
 // Handle the lists used to render actors from other portal areas
@@ -6249,6 +6335,27 @@ void AActor::UpdateRenderSectorList()
 	static const double SPRITE_SPACE = 64.;
 	if (Pos() != OldRenderPos && !(flags & MF_NOSECTOR))
 	{
+		// Only check if the map contains line portals
+		ClearRenderLineList();
+		if (PortalBlockmap.containsLines && Pos().XY() != OldRenderPos.XY())
+		{
+			int bx = GetBlockX(X());
+			int by = GetBlockX(Y());
+			FBoundingBox bb(X(), Y(), MIN(radius*1.5, 128.));	// Don't go further than 128 map units, even for large actors
+			// Are there any portals near the actor's position?
+			if (bx >= 0 && by >= 0 && bx < bmapwidth && by < bmapheight && PortalBlockmap(bx, by).neighborContainsLines)
+			{
+				// Go through the entire list. In most cases this is faster than setting up a blockmap iterator
+				for (auto &p : linePortals)
+				{
+					if (p.mType == PORTT_VISUAL) continue;
+					if (bb.inRange(p.mOrigin) && bb.BoxOnLineSide(p.mOrigin))
+					{
+						render_portallist = P_AddPortalnode(&p, this, render_portallist);
+					}
+				}
+			}
+		}
 		sector_t *sec = Sector;
 		double lasth = -FLT_MAX;
 		ClearRenderSectorList();
@@ -6284,6 +6391,14 @@ void AActor::ClearRenderSectorList()
 	render_sectorlist = NULL;
 }
 
+void AActor::ClearRenderLineList()
+{
+	portnode_t *node = render_portallist;
+	while (node)
+		node = P_DelPortalnode(node);
+	render_portallist = NULL;
+}
+
 
 //==========================================================================
 //
diff --git a/src/portal.cpp b/src/portal.cpp
index 3dfd9a050..6abd4e8da 100644
--- a/src/portal.cpp
+++ b/src/portal.cpp
@@ -119,8 +119,8 @@ static void BuildBlockmap()
 			while (*list != -1)
 			{
 				line_t *ld = &lines[*list++];
-
-				if (ld->isLinePortal())
+				FLinePortal *port = ld->getPortal();
+				if (port && port->mType != PORTT_VISUAL)
 				{
 					PortalBlockmap.containsLines = true;
 					block.portallines.Push(ld);
diff --git a/src/portal.h b/src/portal.h
index 9c05f23b7..bba674def 100644
--- a/src/portal.h
+++ b/src/portal.h
@@ -7,6 +7,7 @@
 
 struct FPortalGroupArray;
 class ASkyViewpoint;
+struct portnode_t;
 //============================================================================
 //
 // This table holds the offsets for the different parts of a map
@@ -189,6 +190,7 @@ struct FLinePortal
 	DAngle mAngleDiff;
 	double mSinRot;
 	double mCosRot;
+	portnode_t *render_thinglist;
 	void *mRenderData;
 };
 
diff --git a/src/r_defs.h b/src/r_defs.h
index 9f04dc2aa..ad043a404 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -1387,6 +1387,18 @@ struct msecnode_t
 	bool visited;	// killough 4/4/98, 4/7/98: used in search algorithms
 };
 
+// use the same memory layout as msecnode_t so both can be used from the same freelist.
+struct portnode_t
+{
+	FLinePortal			*m_portal;	// a portal containing this object
+	AActor				*m_thing;	// this object
+	struct portnode_t	*m_tprev;	// prev msecnode_t for this thing
+	struct portnode_t	*m_tnext;	// next msecnode_t for this thing
+	struct portnode_t	*m_sprev;	// prev msecnode_t for this portal
+	struct portnode_t	*m_snext;	// next msecnode_t for this portal
+	bool visited;
+};
+
 struct FPolyNode;
 struct FMiniBSP;