diff --git a/src/r_data/r_interpolate.cpp b/src/r_data/r_interpolate.cpp
index 3ca3b557c..29f54c39b 100644
--- a/src/r_data/r_interpolate.cpp
+++ b/src/r_data/r_interpolate.cpp
@@ -451,12 +451,12 @@ void DSectorPlaneInterpolation::Restore()
 	if (!ceiling)
 	{
 		sector->floorplane.d = bakheight;
-		sector->SetPlaneTexZ(sector_t::floor, baktexz);
+		sector->SetPlaneTexZ(sector_t::floor, baktexz, true);
 	}
 	else
 	{
 		sector->ceilingplane.d = bakheight;
-		sector->SetPlaneTexZ(sector_t::ceiling, baktexz);
+		sector->SetPlaneTexZ(sector_t::ceiling, baktexz, true);
 	}
 	P_RecalculateAttached3DFloors(sector);
 }
@@ -487,7 +487,7 @@ void DSectorPlaneInterpolation::Interpolate(fixed_t smoothratio)
 	baktexz = sector->GetPlaneTexZ(pos);
 
 	*pheight = oldheight + FixedMul(bakheight - oldheight, smoothratio);
-	sector->SetPlaneTexZ(pos, oldtexz + FixedMul(baktexz - oldtexz, smoothratio));
+	sector->SetPlaneTexZ(pos, oldtexz + FixedMul(baktexz - oldtexz, smoothratio), true);
 	P_RecalculateAttached3DFloors(sector);
 }
 
diff --git a/src/r_defs.h b/src/r_defs.h
index 2a76510f8..d0d538aa5 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -649,10 +649,10 @@ struct sector_t
 		for (unsigned i = 0; i < e->XFloor.attached.Size(); i++) e->XFloor.attached[i]->SetVerticesDirty();
 	}
 
-	void SetPlaneTexZ(int pos, fixed_t val)
+	void SetPlaneTexZ(int pos, fixed_t val, bool dirtify = false)	// This mainly gets used by init code. The only place where it must set the vertex to dirty is the interpolation code.
 	{
 		planes[pos].TexZ = val;
-		SetAllVerticesDirty();
+		if (dirtify) SetAllVerticesDirty();
 	}
 
 	void ChangePlaneTexZ(int pos, fixed_t val)