diff --git a/src/maploader/maploader.h b/src/maploader/maploader.h
index cc7e08187e..93c65f9838 100644
--- a/src/maploader/maploader.h
+++ b/src/maploader/maploader.h
@@ -110,8 +110,6 @@ private:
 	int firstglvertex;	// helpers for loading GL nodes from GWA files.
 	bool format5;
 
-	TArray<vertexdata_t> vertexdatas;
-
 	TMap<unsigned, unsigned>  MapThingsUserDataIndex;	// from mapthing idx -> user data idx
 	TArray<FUDMFKey> MapThingsUserData;
 	int sidecount = 0;
@@ -120,6 +118,8 @@ private:
 public:	// for the scripted compatibility system these two members need to be public.
 	TArray<FMapThing> MapThingsConverted;
 	bool ForceNodeBuild = false;
+	// This needs to be public to fetch this from DLevelPostProcessor native functions
+	TArray<vertexdata_t> vertexdatas;
 private:
 
 	// Extradata loader
diff --git a/src/maploader/postprocessor.cpp b/src/maploader/postprocessor.cpp
index d47b2df8ee..4c0875dbb0 100644
--- a/src/maploader/postprocessor.cpp
+++ b/src/maploader/postprocessor.cpp
@@ -437,6 +437,77 @@ DEFINE_ACTION_FUNCTION(DLevelPostProcessor, SetVertex)
 	return 0;
 }
 
+DEFINE_ACTION_FUNCTION(DLevelPostProcessor, GetVertexZ)
+{
+	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
+	PARAM_UINT(vertex);
+	PARAM_INT(planeval);
+	
+	if (vertex < self->Level->vertexes.Size() && vertex < self->loader->vertexdatas.Size())
+	{
+		vertexdata_t& data = self->loader->vertexdatas[vertex];
+		double value = planeval ? data.zFloor : data.zCeiling;
+		ACTION_RETURN_FLOAT(value);
+	}
+
+	ACTION_RETURN_FLOAT(0);
+}
+
+DEFINE_ACTION_FUNCTION(DLevelPostProcessor, IsVertexZSet)
+{
+	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
+	PARAM_UINT(vertex);
+	PARAM_INT(planeval);
+
+	if (vertex < self->Level->vertexes.Size() && vertex < self->loader->vertexdatas.Size())
+	{
+		vertexdata_t& data = self->loader->vertexdatas[vertex];
+		bool value = data.flags & (planeval ? VERTEXFLAG_ZFloorEnabled : VERTEXFLAG_ZCeilingEnabled);
+		ACTION_RETURN_BOOL(value);
+	}
+
+	ACTION_RETURN_BOOL(false);
+}
+
+DEFINE_ACTION_FUNCTION(DLevelPostProcessor, SetVertexZ)
+{
+	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
+	PARAM_UINT(vertex);
+	PARAM_INT(planeval);
+	PARAM_FLOAT(z);
+
+	if (vertex < self->Level->vertexes.Size() && vertex < self->loader->vertexdatas.Size())
+	{
+		vertexdata_t& data = self->loader->vertexdatas[vertex];
+		if (planeval) {
+			data.flags |= VERTEXFLAG_ZFloorEnabled;
+			data.zFloor = z;
+		}
+		else
+		{
+			data.flags |= VERTEXFLAG_ZCeilingEnabled;
+			data.zCeiling = z;
+		}
+	}
+
+	return 0;
+}
+
+DEFINE_ACTION_FUNCTION(DLevelPostProcessor, UnsetVertexZ)
+{
+	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
+	PARAM_UINT(vertex);
+	PARAM_INT(planeval);
+
+	if (vertex < self->Level->vertexes.Size() && vertex < self->loader->vertexdatas.Size())
+	{
+		vertexdata_t& data = self->loader->vertexdatas[vertex];
+		data.flags &= ~(planeval ? VERTEXFLAG_ZFloorEnabled : VERTEXFLAG_ZCeilingEnabled);
+	}
+
+	return 0;
+}
+
 DEFINE_ACTION_FUNCTION(DLevelPostProcessor, SetLineVertexes)
 {
 	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
diff --git a/wadsrc/static/zscript/level_postprocessor.zs b/wadsrc/static/zscript/level_postprocessor.zs
index 93ee8343de..266ad6404c 100644
--- a/wadsrc/static/zscript/level_postprocessor.zs
+++ b/wadsrc/static/zscript/level_postprocessor.zs
@@ -47,6 +47,10 @@ class LevelPostProcessor native play
 	protected native void SetThingStringArgument(uint thing, Name value);
 
 	protected native void SetVertex(uint vertex, double x, double y);
+	protected native double GetVertexZ(uint vertex, int plane);
+	protected native bool IsVertexZSet(uint vertex, int plane);
+	protected native void SetVertexZ(uint vertex, int plane, double z);
+	protected native void UnsetVertexZ(uint vertex, int plane);
 	protected native void SetLineVertexes(uint Line, uint v1, uint v2);
 	protected native void FlipLineSideRefs(uint Line);
 	protected native void SetLineSectorRef(uint line, uint side, uint sector);