diff --git a/src/Blocks/MetaRotater.h b/src/Blocks/MetaRotater.h
index f1656f1bd..b83ed177a 100644
--- a/src/Blocks/MetaRotater.h
+++ b/src/Blocks/MetaRotater.h
@@ -1,7 +1,7 @@
 
 #pragma once
 
-template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West>
+template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched = false>
 class cMetaRotater : public Base
 {
 public:
@@ -19,64 +19,70 @@ public:
 };
 
 
-template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West>
-NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West>::MetaRotateCW(NIBBLETYPE a_Meta)
+template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West, AssertIfNotMatched>::MetaRotateCW(NIBBLETYPE a_Meta)
 {
-NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
-switch (a_Meta & BitFilter)
-{
-case South: return West  | OtherMeta; 
-case West:  return North | OtherMeta; 
-case North: return East  | OtherMeta;
-case East:  return South | OtherMeta;
-}
-ASSERT(!"Invalid Meta value");
-return a_Meta;
+	NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
+	switch (a_Meta & BitFilter)
+	{
+		case South: return West  | OtherMeta; 
+		case West:  return North | OtherMeta; 
+		case North: return East  | OtherMeta;
+		case East:  return South | OtherMeta;
+	}
+	if(AssertIfNotMatched)
+	{
+		ASSERT(!"Invalid Meta value");
+		return a_Meta;
+	}
 }
 
 
-template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West>
-NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West>::MetaRotateCCW(NIBBLETYPE a_Meta)
+template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West, AssertIfNotMatched>::MetaRotateCCW(NIBBLETYPE a_Meta)
 {
-NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
-switch (a_Meta & BitFilter)
-{
-case South: return East  | OtherMeta; 
-case East:  return North | OtherMeta;
-case North: return West  | OtherMeta;
-case West:  return South | OtherMeta;
-}
-ASSERT(!"Invalid Meta value");
-return a_Meta;
+	NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
+	switch (a_Meta & BitFilter)
+	{
+		case South: return East  | OtherMeta; 
+		case East:  return North | OtherMeta;
+		case North: return West  | OtherMeta;
+		case West:  return South | OtherMeta;
+	}
+	if(AssertIfNotMatched)
+	{
+		ASSERT(!"Invalid Meta value");
+		return a_Meta;
+	}
 }
 
 
 
-template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West>
-NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West>::MetaMirrorXY(NIBBLETYPE a_Meta)
+template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West, AssertIfNotMatched>::MetaMirrorXY(NIBBLETYPE a_Meta)
 {
-NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
-switch (a_Meta & BitFilter)
-{
-case South: return North | OtherMeta;
-case North: return South | OtherMeta;
-}
-// Not Facing North or South; No change.
-return a_Meta;
+	NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
+	switch (a_Meta & BitFilter)
+	{
+		case South: return North | OtherMeta;
+		case North: return South | OtherMeta;
+	}
+	// Not Facing North or South; No change.
+	return a_Meta;
 }
 
 
 
 
-template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West>
-NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West>::MetaMirrorYZ(NIBBLETYPE a_Meta)
+template<class Base, NIBBLETYPE BitFilter, NIBBLETYPE North, NIBBLETYPE East, NIBBLETYPE South, NIBBLETYPE West, bool AssertIfNotMatched>
+NIBBLETYPE cMetaRotater<Base, BitFilter, North, East, South, West, AssertIfNotMatched>::MetaMirrorYZ(NIBBLETYPE a_Meta)
 {
-NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
-switch (a_Meta & BitFilter)
-{
-case West: return East | OtherMeta;
-case East: return West | OtherMeta;
-}
-// Not Facing East or West; No change.
-return a_Meta;
+	NIBBLETYPE OtherMeta = a_Meta & (~BitFilter);
+	switch (a_Meta & BitFilter)
+	{
+		case West: return East | OtherMeta;
+		case East: return West | OtherMeta;
+	}
+	// Not Facing East or West; No change.
+	return a_Meta;
 }