diff --git a/wadsrc/static/zscript/base.txt b/wadsrc/static/zscript/base.txt
index 30df80759..0ed93c528 100644
--- a/wadsrc/static/zscript/base.txt
+++ b/wadsrc/static/zscript/base.txt
@@ -478,11 +478,12 @@ enum ETraceStatus
 
 enum ETraceFlags
 {
-	TRACE_NoSky		= 1,	// Hitting the sky returns TRACE_HitNone
-	//TRACE_PCross		= 2,	// Trigger SPAC_PCROSS lines
-	//TRACE_Impact		= 4,	// Trigger SPAC_IMPACT lines
-	TRACE_PortalRestrict	= 8,	// Cannot go through portals without a static link offset.
-	TRACE_ReportPortals	= 16	// Report any portal crossing to the TraceCallback
+	TRACE_NoSky		= 0x0001,	// Hitting the sky returns TRACE_HitNone
+	//TRACE_PCross		= 0x0002,	// Trigger SPAC_PCROSS lines
+	//TRACE_Impact		= 0x0004,	// Trigger SPAC_IMPACT lines
+	TRACE_PortalRestrict	= 0x0008,	// Cannot go through portals without a static link offset.
+	TRACE_ReportPortals	= 0x0010,	// Report any portal crossing to the TraceCallback
+	//TRACE_3DCallback	= 0x0020,	// [ZZ] use TraceCallback to determine whether we need to go through a line to do 3D floor check, or not. without this, only line flag mask is used
 }