diff --git a/src/p_maputl.c b/src/p_maputl.c
index 5750dc03d..0693c20b3 100644
--- a/src/p_maputl.c
+++ b/src/p_maputl.c
@@ -607,10 +607,20 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 	int hi = 0;
 	int lo = 0;
 
+	// set these defaults so that polyobjects don't interfere with collision above or below them
+	opentop = highceiling = INT32_MAX;
+	openbottom = lowfloor = INT32_MIN;
+	openrange = 0;
+	opentopslope = openbottomslope = NULL;
+	opentoppic = openbottompic = -1;
+	openceilingstep = 0;
+	openceilingdrop = 0;
+	openfloorstep = 0;
+	openfloordrop = 0;
+
 	if (linedef->sidenum[1] == 0xffff)
 	{
 		// single sided line
-		openrange = 0;
 		return;
 	}
 
@@ -637,22 +647,9 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 	}
 
 	openfloorrover = openceilingrover = NULL;
-	if (linedef->polyobj)
+	if (!linedef->polyobj)
 	{
-		// set these defaults so that polyobjects don't interfere with collision above or below them
-		opentop = INT32_MAX;
-		openbottom = INT32_MIN;
-		highceiling = INT32_MIN;
-		lowfloor = INT32_MAX;
-		opentopslope = openbottomslope = NULL;
-		opentoppic = openbottompic = -1;
-		openceilingstep = 0;
-		openceilingdrop = 0;
-		openfloorstep = 0;
-		openfloordrop = 0;
-	}
-	else
-	{ // Set open and high/low values here
+		// Set open and high/low values here
 		fixed_t          height[2];
 		const sector_t * sector[2] = { front, back };
 
@@ -774,8 +771,7 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 						highceiling = polybottom;
 					}
 				}
-
-				if (delta1 <= delta2)
+				else
 				{
 					if (polytop > openbottom)
 					{
@@ -842,8 +838,7 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 							}
 						}
 					}
-
-					if (delta1 <= delta2)
+					else
 					{
 						// thing is above FOF
 						if ((rover->fofflags & FOF_INTANGIBLEFLATS) != FOF_REVERSEPLATFORM)
@@ -890,8 +885,7 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 							}
 						}
 					}
-
-					if (delta1 <= delta2)
+					else
 					{
 						// thing is above FOF
 						if ((rover->fofflags & FOF_INTANGIBLEFLATS) != FOF_REVERSEPLATFORM)
@@ -953,14 +947,14 @@ void P_LineOpening(line_t *linedef, mobj_t *mobj)
 					openfloorstep = ( botedge[hi] - mobj->z );
 					openfloordrop = ( botedge[hi] - botedge[lo] );
 
-					if (open[lo].top > lowfloor)
+					if (open[lo].bottom > lowfloor)
 					{
-						lowfloor = open[lo].top;
+						lowfloor = open[lo].bottom;
 					}
 				}
-				else if (open[hi].top > lowfloor)
+				else if (open[hi].bottom > lowfloor)
 				{
-					lowfloor = open[hi].top;
+					lowfloor = open[hi].bottom;
 				}
 			}
 		}
diff --git a/src/p_sight.c b/src/p_sight.c
index a516a288b..901e1003f 100644
--- a/src/p_sight.c
+++ b/src/p_sight.c
@@ -444,9 +444,38 @@ static boolean P_CanWaypointTraverse(seg_t *seg, divline_t *divl, register los_t
 	tm.x = los->strace.x + FixedMul(los->strace.dx, frac);
 	tm.y = los->strace.y + FixedMul(los->strace.dy, frac);
 
+	// set openrange, opentop, openbottom
 	P_LineOpening(line, los->t1);
 	maxstep = P_GetThingStepUp(los->t1, tm.x, tm.y);
 
+#if 0
+	if (los->t2->type == MT_WAYPOINT)
+	{
+		waypoint_t *wp = K_SearchWaypointHeapForMobj(los->t2);
+
+		if (wp != NULL)
+		{
+			CONS_Printf(
+				"========\nID: %d\nopenrange: %.2f >= %.2f\n",
+				K_GetWaypointID(wp),
+				FIXED_TO_FLOAT(openrange),
+				FIXED_TO_FLOAT(los->t1->height)
+			);
+
+			if (openrange >= los->t1->height)
+			{
+				CONS_Printf(
+					"openbottom: %.2f\nlowfloor: %.2f\nstep: %.2f <= %.2f\n",
+					FIXED_TO_FLOAT(openbottom),
+					FIXED_TO_FLOAT(lowfloor),
+					FIXED_TO_FLOAT(openbottom - lowfloor),
+					FIXED_TO_FLOAT(maxstep)
+				);
+			}
+		}
+	}
+#endif
+
 	if (openrange < los->t1->height)
 	{
 		// Can't fit
@@ -459,7 +488,12 @@ static boolean P_CanWaypointTraverse(seg_t *seg, divline_t *divl, register los_t
 	// Or if we're on the higher side...
 	canDropOff = (flip ? (los->t1->z + los->t1->height <= opentop) : (los->t1->z >= openbottom));
 
-	return (canStepUp || canDropOff);
+	if (canStepUp || canDropOff)
+	{
+		return true;
+	}
+
+	return false;
 }
 
 //