diff --git a/src/actor.h b/src/actor.h
index b371fdaee..52b746ef8 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -1252,6 +1252,15 @@ public:
 		fixedvec3 ret = { X(), Y(), Z() };
 		return ret;
 	}
+	fixedvec3 InterpolatedPosition(fixed_t ticFrac) const
+	{
+		fixedvec3 ret;
+
+		ret.x = PrevX + FixedMul (ticFrac, X() - PrevX);
+		ret.y = PrevY + FixedMul (ticFrac, Y() - PrevY);
+		ret.z = PrevZ + FixedMul (ticFrac, Z() - PrevZ);
+		return ret;
+	}
 	fixedvec3 PosPlusZ(fixed_t zadd) const
 	{
 		fixedvec3 ret = { X(), Y(), Z() + zadd };
diff --git a/src/g_shared/shared_hud.cpp b/src/g_shared/shared_hud.cpp
index b2f1184ea..0fe8a4588 100644
--- a/src/g_shared/shared_hud.cpp
+++ b/src/g_shared/shared_hud.cpp
@@ -826,9 +826,9 @@ static void DrawCoordinates(player_t * CPlayer)
 	
 	if (!map_point_coordinates || !automapactive) 
 	{
-		x=CPlayer->mo->x;
-		y=CPlayer->mo->y;                     
-		z=CPlayer->mo->z;
+		x=CPlayer->mo->X();
+		y=CPlayer->mo->Y();                     
+		z=CPlayer->mo->Z();
 	}
 	else 
 	{
diff --git a/src/g_shared/shared_sbar.cpp b/src/g_shared/shared_sbar.cpp
index b74350633..b351212d0 100644
--- a/src/g_shared/shared_sbar.cpp
+++ b/src/g_shared/shared_sbar.cpp
@@ -1286,7 +1286,8 @@ void DBaseStatusBar::Draw (EHudState state)
 				y -= height * 2;
 		}
 
-		value = &CPlayer->mo->z;
+		fixedvec3 pos = CPlayer->mo->Pos();
+		value = &pos.z;
 		for (i = 2, value = &CPlayer->mo->z; i >= 0; y -= height, --value, --i)
 		{
 			mysnprintf (line, countof(line), "%c: %d", labels[i], *value >> FRACBITS);
diff --git a/src/g_strife/a_alienspectres.cpp b/src/g_strife/a_alienspectres.cpp
index 2b9f499e9..c6339f33d 100644
--- a/src/g_strife/a_alienspectres.cpp
+++ b/src/g_strife/a_alienspectres.cpp
@@ -22,7 +22,7 @@ AActor *P_SpawnSubMissile (AActor *source, const PClass *type, AActor *target);
 
 DEFINE_ACTION_FUNCTION(AActor, A_SpectreChunkSmall)
 {
-	AActor *foo = Spawn("AlienChunkSmall", self->x, self->y, self->z + 10*FRACUNIT, ALLOW_REPLACE);
+	AActor *foo = Spawn("AlienChunkSmall", self->PosPlusZ(10*FRACUNIT), ALLOW_REPLACE);
 
 	if (foo != NULL)
 	{
@@ -40,7 +40,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SpectreChunkSmall)
 
 DEFINE_ACTION_FUNCTION(AActor, A_SpectreChunkLarge)
 {
-	AActor *foo = Spawn("AlienChunkLarge", self->x, self->y, self->z + 10*FRACUNIT, ALLOW_REPLACE);
+	AActor *foo = Spawn("AlienChunkLarge", self->PosPlusZ(10*FRACUNIT), ALLOW_REPLACE);
 
 	if (foo != NULL)
 	{
@@ -62,7 +62,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_Spectre3Attack)
 	if (self->target == NULL)
 		return;
 
-	AActor *foo = Spawn("SpectralLightningV2", self->x, self->y, self->z + 32*FRACUNIT, ALLOW_REPLACE);
+	AActor *foo = Spawn("SpectralLightningV2", self->PosPlusZ(32*FRACUNIT), ALLOW_REPLACE);
 
 	foo->velz = -12*FRACUNIT;
 	foo->target = self;
diff --git a/src/g_strife/a_coin.cpp b/src/g_strife/a_coin.cpp
index dd3610039..36b531001 100644
--- a/src/g_strife/a_coin.cpp
+++ b/src/g_strife/a_coin.cpp
@@ -80,22 +80,22 @@ AInventory *ACoin::CreateTossable ()
 	if (Amount >= 50)
 	{
 		Amount -= 50;
-		tossed = static_cast<ACoin*>(Spawn("Gold50", Owner->x, Owner->y, Owner->z, NO_REPLACE));
+		tossed = static_cast<ACoin*>(Spawn("Gold50", Owner->Pos(), NO_REPLACE));
 	}
 	else if (Amount >= 25)
 	{
 		Amount -= 25;
-		tossed = static_cast<ACoin*>(Spawn("Gold25", Owner->x, Owner->y, Owner->z, NO_REPLACE));
+		tossed = static_cast<ACoin*>(Spawn("Gold25", Owner->Pos(), NO_REPLACE));
 	}
 	else if (Amount >= 10)
 	{
 		Amount -= 10;
-		tossed = static_cast<ACoin*>(Spawn("Gold10", Owner->x, Owner->y, Owner->z, NO_REPLACE));
+		tossed = static_cast<ACoin*>(Spawn("Gold10", Owner->Pos(), NO_REPLACE));
 	}
 	else if (Amount > 1 || (ItemFlags & IF_KEEPDEPLETED))
 	{
 		Amount -= 1;
-		tossed = static_cast<ACoin*>(Spawn("Coin", Owner->x, Owner->y, Owner->z, NO_REPLACE));
+		tossed = static_cast<ACoin*>(Spawn("Coin", Owner->Pos(), NO_REPLACE));
 	}
 	else // Amount == 1 && !(ItemFlags & IF_KEEPDEPLETED)
 	{
diff --git a/src/g_strife/a_crusader.cpp b/src/g_strife/a_crusader.cpp
index cf5f03a23..8655e10bc 100644
--- a/src/g_strife/a_crusader.cpp
+++ b/src/g_strife/a_crusader.cpp
@@ -27,18 +27,18 @@ DEFINE_ACTION_FUNCTION(AActor, A_CrusaderChoose)
 	{
 		A_FaceTarget (self);
 		self->angle -= ANGLE_180/16;
-		P_SpawnMissileZAimed (self, self->z + 40*FRACUNIT, self->target, PClass::FindClass("FastFlameMissile"));
+		P_SpawnMissileZAimed (self, self->Z() + 40*FRACUNIT, self->target, PClass::FindClass("FastFlameMissile"));
 	}
 	else
 	{
 		if (P_CheckMissileRange (self))
 		{
 			A_FaceTarget (self);
-			P_SpawnMissileZAimed (self, self->z + 56*FRACUNIT, self->target, PClass::FindClass("CrusaderMissile"));
+			P_SpawnMissileZAimed (self, self->Z() + 56*FRACUNIT, self->target, PClass::FindClass("CrusaderMissile"));
 			self->angle -= ANGLE_45/32;
-			P_SpawnMissileZAimed (self, self->z + 40*FRACUNIT, self->target, PClass::FindClass("CrusaderMissile"));
+			P_SpawnMissileZAimed (self, self->Z() + 40*FRACUNIT, self->target, PClass::FindClass("CrusaderMissile"));
 			self->angle += ANGLE_45/16;
-			P_SpawnMissileZAimed (self, self->z + 40*FRACUNIT, self->target, PClass::FindClass("CrusaderMissile"));
+			P_SpawnMissileZAimed (self, self->Z() + 40*FRACUNIT, self->target, PClass::FindClass("CrusaderMissile"));
 			self->angle -= ANGLE_45/16;
 			self->reactiontime += 15;
 		}
@@ -49,7 +49,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_CrusaderChoose)
 DEFINE_ACTION_FUNCTION(AActor, A_CrusaderSweepLeft)
 {
 	self->angle += ANGLE_90/16;
-	AActor *misl = P_SpawnMissileZAimed (self, self->z + 48*FRACUNIT, self->target, PClass::FindClass("FastFlameMissile"));
+	AActor *misl = P_SpawnMissileZAimed (self, self->Z() + 48*FRACUNIT, self->target, PClass::FindClass("FastFlameMissile"));
 	if (misl != NULL)
 	{
 		misl->velz += FRACUNIT;
@@ -59,7 +59,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_CrusaderSweepLeft)
 DEFINE_ACTION_FUNCTION(AActor, A_CrusaderSweepRight)
 {
 	self->angle -= ANGLE_90/16;
-	AActor *misl = P_SpawnMissileZAimed (self, self->z + 48*FRACUNIT, self->target, PClass::FindClass("FastFlameMissile"));
+	AActor *misl = P_SpawnMissileZAimed (self, self->Z() + 48*FRACUNIT, self->target, PClass::FindClass("FastFlameMissile"));
 	if (misl != NULL)
 	{
 		misl->velz += FRACUNIT;
diff --git a/src/g_strife/a_entityboss.cpp b/src/g_strife/a_entityboss.cpp
index fafb3b862..04b586b67 100644
--- a/src/g_strife/a_entityboss.cpp
+++ b/src/g_strife/a_entityboss.cpp
@@ -24,7 +24,7 @@ void A_SpectralMissile (AActor *self, const char *missilename)
 {
 	if (self->target != NULL)
 	{
-		AActor *missile = P_SpawnMissileXYZ (self->x, self->y, self->z + 32*FRACUNIT, 
+		AActor *missile = P_SpawnMissileXYZ (self->PosPlusZ(32*FRACUNIT), 
 			self, self->target, PClass::FindClass(missilename), false);
 		if (missile != NULL)
 		{
@@ -70,7 +70,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_EntityAttack)
 
 DEFINE_ACTION_FUNCTION(AActor, A_SpawnEntity)
 {
-	AActor *entity = Spawn("EntityBoss", self->x, self->y, self->z + 70*FRACUNIT, ALLOW_REPLACE);
+	AActor *entity = Spawn("EntityBoss", self->PosPlusZ(70*FRACUNIT), ALLOW_REPLACE);
 	if (entity != NULL)
 	{
 		entity->angle = self->angle;
@@ -89,13 +89,10 @@ DEFINE_ACTION_FUNCTION(AActor, A_EntityDeath)
 	AActor *spot = self->tracer;
 	if (spot == NULL) spot = self;
 
-	fixed_t SpawnX = spot->x;
-	fixed_t SpawnY = spot->y;
-	fixed_t SpawnZ = spot->z + (self->tracer? 70*FRACUNIT : 0);
+	fixedvec3 pos = spot->Vec3Angle(secondRadius, self->angle, self->tracer? 70*FRACUNIT : 0);
 	
 	an = self->angle >> ANGLETOFINESHIFT;
-	second = Spawn("EntitySecond", SpawnX + FixedMul (secondRadius, finecosine[an]),
-		SpawnY + FixedMul (secondRadius, finesine[an]), SpawnZ, ALLOW_REPLACE);
+	second = Spawn("EntitySecond", pos, ALLOW_REPLACE);
 	second->CopyFriendliness(self, true);
 	//second->target = self->target;
 	A_FaceTarget (second);
@@ -103,18 +100,18 @@ DEFINE_ACTION_FUNCTION(AActor, A_EntityDeath)
 	second->velx += FixedMul (finecosine[an], 320000);
 	second->vely += FixedMul (finesine[an], 320000);
 
+	pos = spot->Vec3Angle(secondRadius, self->angle + ANGLE_90, self->tracer? 70*FRACUNIT : 0);
 	an = (self->angle + ANGLE_90) >> ANGLETOFINESHIFT;
-	second = Spawn("EntitySecond", SpawnX + FixedMul (secondRadius, finecosine[an]),
-		SpawnY + FixedMul (secondRadius, finesine[an]), SpawnZ, ALLOW_REPLACE);
+	second = Spawn("EntitySecond", pos, ALLOW_REPLACE);
 	second->CopyFriendliness(self, true);
 	//second->target = self->target;
 	second->velx = FixedMul (secondRadius, finecosine[an]) << 2;
 	second->vely = FixedMul (secondRadius, finesine[an]) << 2;
 	A_FaceTarget (second);
 
+	pos = spot->Vec3Angle(secondRadius, self->angle - ANGLE_90, self->tracer? 70*FRACUNIT : 0);
 	an = (self->angle - ANGLE_90) >> ANGLETOFINESHIFT;
-	second = Spawn("EntitySecond", SpawnX + FixedMul (secondRadius, finecosine[an]),
-		SpawnY + FixedMul (secondRadius, finesine[an]), SpawnZ, ALLOW_REPLACE);
+	second = Spawn("EntitySecond", pos, ALLOW_REPLACE);
 	second->CopyFriendliness(self, true);
 	//second->target = self->target;
 	second->velx = FixedMul (secondRadius, finecosine[an]) << 2;
diff --git a/src/g_strife/a_inquisitor.cpp b/src/g_strife/a_inquisitor.cpp
index 1a0739d36..b93933422 100644
--- a/src/g_strife/a_inquisitor.cpp
+++ b/src/g_strife/a_inquisitor.cpp
@@ -35,9 +35,9 @@ DEFINE_ACTION_FUNCTION(AActor, A_InquisitorDecide)
 	{
 		self->SetState (self->FindState("Grenade"));
 	}
-	if (self->target->z != self->z)
+	if (self->target->Z() != self->Z())
 	{
-		if (self->z + self->height + 54*FRACUNIT < self->ceilingz)
+		if (self->Top() + 54*FRACUNIT < self->ceilingz)
 		{
 			self->SetState (self->FindState("Jump"));
 		}
@@ -53,20 +53,20 @@ DEFINE_ACTION_FUNCTION(AActor, A_InquisitorAttack)
 
 	A_FaceTarget (self);
 
-	self->z += 32*FRACUNIT;
+	self->AddZ(32*FRACUNIT);
 	self->angle -= ANGLE_45/32;
-	proj = P_SpawnMissileZAimed (self, self->z, self->target, PClass::FindClass("InquisitorShot"));
+	proj = P_SpawnMissileZAimed (self, self->Z(), self->target, PClass::FindClass("InquisitorShot"));
 	if (proj != NULL)
 	{
 		proj->velz += 9*FRACUNIT;
 	}
 	self->angle += ANGLE_45/16;
-	proj = P_SpawnMissileZAimed (self, self->z, self->target, PClass::FindClass("InquisitorShot"));
+	proj = P_SpawnMissileZAimed (self, self->Z(), self->target, PClass::FindClass("InquisitorShot"));
 	if (proj != NULL)
 	{
 		proj->velz += 16*FRACUNIT;
 	}
-	self->z -= 32*FRACUNIT;
+	self->AddZ(-32*FRACUNIT);
 }
 
 DEFINE_ACTION_FUNCTION(AActor, A_InquisitorJump)
@@ -79,7 +79,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_InquisitorJump)
 		return;
 
 	S_Sound (self, CHAN_ITEM|CHAN_LOOP, "inquisitor/jump", 1, ATTN_NORM);
-	self->z += 64*FRACUNIT;
+	self->AddZ(64*FRACUNIT);
 	A_FaceTarget (self);
 	an = self->angle >> ANGLETOFINESHIFT;
 	speed = self->Speed * 2/3;
@@ -91,7 +91,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_InquisitorJump)
 	{
 		dist = 1;
 	}
-	self->velz = (self->target->z - self->z) / dist;
+	self->velz = (self->target->Z() - self->Z()) / dist;
 	self->reactiontime = 60;
 	self->flags |= MF_NOGRAVITY;
 }
@@ -102,7 +102,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_InquisitorCheckLand)
 	if (self->reactiontime < 0 ||
 		self->velx == 0 ||
 		self->vely == 0 ||
-		self->z <= self->floorz)
+		self->Z() <= self->floorz)
 	{
 		self->SetState (self->SeeState);
 		self->reactiontime = 0;
@@ -119,7 +119,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_InquisitorCheckLand)
 
 DEFINE_ACTION_FUNCTION(AActor, A_TossArm)
 {
-	AActor *foo = Spawn("InquisitorArm", self->x, self->y, self->z + 24*FRACUNIT, ALLOW_REPLACE);
+	AActor *foo = Spawn("InquisitorArm", self->PosPlusZ(24*FRACUNIT), ALLOW_REPLACE);
 	foo->angle = self->angle - ANGLE_90 + (pr_inq.Random2() << 22);
 	foo->velx = FixedMul (foo->Speed, finecosine[foo->angle >> ANGLETOFINESHIFT]) >> 3;
 	foo->vely = FixedMul (foo->Speed, finesine[foo->angle >> ANGLETOFINESHIFT]) >> 3;
diff --git a/src/g_strife/a_loremaster.cpp b/src/g_strife/a_loremaster.cpp
index d984bbdd3..1b12c2436 100644
--- a/src/g_strife/a_loremaster.cpp
+++ b/src/g_strife/a_loremaster.cpp
@@ -21,16 +21,14 @@ IMPLEMENT_CLASS (ALoreShot)
 
 int ALoreShot::DoSpecialDamage (AActor *victim, int damage, FName damagetype)
 {
-	FVector3 thrust;
 	
 	if (victim != NULL && target != NULL && !(victim->flags7 & MF7_DONTTHRUST))
 	{
-		thrust.X = float(target->x - victim->x);
-		thrust.Y = float(target->y - victim->y);
-		thrust.Z = float(target->z - victim->z);
-	
+		fixedvec3 fixthrust = victim->Vec3To(target);
+		TVector3<double> thrust(fixthrust.x, fixthrust.y, fixthrust.z);
+
 		thrust.MakeUnit();
-		thrust *= float((255*50*FRACUNIT) / (victim->Mass ? victim->Mass : 1));
+		thrust *= double((255*50*FRACUNIT) / (victim->Mass ? victim->Mass : 1));
 	
 		victim->velx += fixed_t(thrust.X);
 		victim->vely += fixed_t(thrust.Y);
@@ -42,7 +40,7 @@ int ALoreShot::DoSpecialDamage (AActor *victim, int damage, FName damagetype)
 DEFINE_ACTION_FUNCTION(AActor, A_LoremasterChain)
 {
 	S_Sound (self, CHAN_BODY, "loremaster/active", 1, ATTN_NORM);
-	Spawn("LoreShot2", self->x, self->y, self->z, ALLOW_REPLACE);
-	Spawn("LoreShot2", self->x - (self->velx >> 1), self->y - (self->vely >> 1), self->z - (self->velz >> 1), ALLOW_REPLACE);
-	Spawn("LoreShot2", self->x - self->velx, self->y - self->vely, self->z - self->velz, ALLOW_REPLACE);
+	Spawn("LoreShot2", self->Pos(), ALLOW_REPLACE);
+	Spawn("LoreShot2", self->Vec3Offset(-(self->velx >> 1), -(self->vely >> 1), -(self->velz >> 1)), ALLOW_REPLACE);
+	Spawn("LoreShot2", self->Vec3Offset(-self->velx, -self->vely, -self->velz), ALLOW_REPLACE);
 }
diff --git a/src/g_strife/a_programmer.cpp b/src/g_strife/a_programmer.cpp
index 78689468b..5835b3566 100644
--- a/src/g_strife/a_programmer.cpp
+++ b/src/g_strife/a_programmer.cpp
@@ -104,7 +104,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SpotLightning)
 	if (self->target == NULL)
 		return;
 
-	spot = Spawn("SpectralLightningSpot", self->target->x, self->target->y, self->target->floorz, ALLOW_REPLACE);
+	spot = Spawn("SpectralLightningSpot", self->target->X(), self->target->Y(), self->target->floorz, ALLOW_REPLACE);
 	if (spot != NULL)
 	{
 		spot->threshold = 25;
@@ -122,7 +122,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SpotLightning)
 
 DEFINE_ACTION_FUNCTION(AActor, A_SpawnProgrammerBase)
 {
-	AActor *foo = Spawn("ProgrammerBase", self->x, self->y, self->z + 24*FRACUNIT, ALLOW_REPLACE);
+	AActor *foo = Spawn("ProgrammerBase", self->PosPlusZ(24*FRACUNIT), ALLOW_REPLACE);
 	if (foo != NULL)
 	{
 		foo->angle = self->angle + ANGLE_180 + (pr_prog.Random2() << 22);
diff --git a/src/g_strife/a_rebels.cpp b/src/g_strife/a_rebels.cpp
index 81490c361..6c8652f7c 100644
--- a/src/g_strife/a_rebels.cpp
+++ b/src/g_strife/a_rebels.cpp
@@ -75,8 +75,8 @@ DEFINE_ACTION_FUNCTION(AActor, A_Beacon)
 	AActor *rebel;
 	angle_t an;
 
-	rebel = Spawn("Rebel1", self->x, self->y, self->floorz, ALLOW_REPLACE);
-	if (!P_TryMove (rebel, rebel->x, rebel->y, true))
+	rebel = Spawn("Rebel1", self->X(), self->Y(), self->floorz, ALLOW_REPLACE);
+	if (!P_TryMove (rebel, rebel->X(), rebel->Y(), true))
 	{
 		rebel->Destroy ();
 		return;
@@ -112,7 +112,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_Beacon)
 	rebel->SetState (rebel->SeeState);
 	rebel->angle = self->angle;
 	an = self->angle >> ANGLETOFINESHIFT;
-	Spawn<ATeleportFog> (rebel->x + 20*finecosine[an], rebel->y + 20*finesine[an], rebel->z + TELEFOGHEIGHT, ALLOW_REPLACE);
+	Spawn<ATeleportFog> (rebel->Vec3Offset(20*finecosine[an], 20*finesine[an], TELEFOGHEIGHT), ALLOW_REPLACE);
 	if (--self->health < 0)
 	{
 		self->SetState(self->FindState(NAME_Death));
diff --git a/src/g_strife/a_sentinel.cpp b/src/g_strife/a_sentinel.cpp
index 74f0e917f..550a89ff7 100644
--- a/src/g_strife/a_sentinel.cpp
+++ b/src/g_strife/a_sentinel.cpp
@@ -27,7 +27,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SentinelBob)
 	{
 		minz = maxz;
 	}
-	if (minz < self->z)
+	if (minz < self->Z())
 	{
 		self->velz -= FRACUNIT;
 	}
@@ -35,7 +35,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SentinelBob)
 	{
 		self->velz += FRACUNIT;
 	}
-	self->reactiontime = (minz >= self->z) ? 4 : 0;
+	self->reactiontime = (minz >= self->Z()) ? 4 : 0;
 }
 
 DEFINE_ACTION_FUNCTION(AActor, A_SentinelAttack)
@@ -48,16 +48,14 @@ DEFINE_ACTION_FUNCTION(AActor, A_SentinelAttack)
 		return;
 	}
 
-	missile = P_SpawnMissileZAimed (self, self->z + 32*FRACUNIT, self->target, PClass::FindClass("SentinelFX2"));
+	missile = P_SpawnMissileZAimed (self, self->Z() + 32*FRACUNIT, self->target, PClass::FindClass("SentinelFX2"));
 
 	if (missile != NULL && (missile->velx | missile->vely) != 0)
 	{
 		for (int i = 8; i > 1; --i)
 		{
 			trail = Spawn("SentinelFX1",
-				self->x + FixedMul (missile->radius * i, finecosine[missile->angle >> ANGLETOFINESHIFT]),
-				self->y + FixedMul (missile->radius * i, finesine[missile->angle >> ANGLETOFINESHIFT]),
-				missile->z + (missile->velz / 4 * i), ALLOW_REPLACE);
+				self->Vec3Angle(missile->radius*i, missile->angle, (missile->velz / 4 * i)), ALLOW_REPLACE);
 			if (trail != NULL)
 			{
 				trail->target = self;
@@ -67,7 +65,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SentinelAttack)
 				P_CheckMissileSpawn (trail, self->radius);
 			}
 		}
-		missile->z += missile->velz >> 2;
+		missile->AddZ(missile->velz >> 2);
 	}
 }
 
diff --git a/src/g_strife/a_spectral.cpp b/src/g_strife/a_spectral.cpp
index 6f80fe42c..91e43dba9 100644
--- a/src/g_strife/a_spectral.cpp
+++ b/src/g_strife/a_spectral.cpp
@@ -28,7 +28,7 @@ void ASpectralMonster::Touch (AActor *toucher)
 
 DEFINE_ACTION_FUNCTION(AActor, A_SpectralLightningTail)
 {
-	AActor *foo = Spawn("SpectralLightningHTail", self->x - self->velx, self->y - self->vely, self->z, ALLOW_REPLACE);
+	AActor *foo = Spawn("SpectralLightningHTail", self->Vec3Offset(-self->velx, -self->vely, 0), ALLOW_REPLACE);
 
 	foo->angle = self->angle;
 	foo->FriendPlayer = self->FriendPlayer;
@@ -61,17 +61,18 @@ DEFINE_ACTION_FUNCTION(AActor, A_SpectralLightning)
 	self->velx += pr_zap5.Random2(3) << FRACBITS;
 	self->vely += pr_zap5.Random2(3) << FRACBITS;
 
-	x = self->x + pr_zap5.Random2(3) * FRACUNIT * 50;
-	y = self->y + pr_zap5.Random2(3) * FRACUNIT * 50;
+	fixedvec2 pos = self->Vec2Offset(
+		pr_zap5.Random2(3) * FRACUNIT * 50,
+		pr_zap5.Random2(3) * FRACUNIT * 50);
 
 	flash = Spawn (self->threshold > 25 ? PClass::FindClass(NAME_SpectralLightningV2) :
-		PClass::FindClass(NAME_SpectralLightningV1), x, y, ONCEILINGZ, ALLOW_REPLACE);
+		PClass::FindClass(NAME_SpectralLightningV1), pos.x, pos.y, ONCEILINGZ, ALLOW_REPLACE);
 
 	flash->target = self->target;
 	flash->velz = -18*FRACUNIT;
 	flash->FriendPlayer = self->FriendPlayer;
 
-	flash = Spawn(NAME_SpectralLightningV2, self->x, self->y, ONCEILINGZ, ALLOW_REPLACE);
+	flash = Spawn(NAME_SpectralLightningV2, self->X(), self->Y(), ONCEILINGZ, ALLOW_REPLACE);
 
 	flash->target = self->target;
 	flash->velz = -18*FRACUNIT;
@@ -128,11 +129,11 @@ DEFINE_ACTION_FUNCTION(AActor, A_Tracer2)
 		}
 		if (dest->height >= 56*FRACUNIT)
 		{
-			slope = (dest->z+40*FRACUNIT - self->z) / dist;
+			slope = (dest->Z()+40*FRACUNIT - self->Z()) / dist;
 		}
 		else
 		{
-			slope = (dest->z + self->height*2/3 - self->z) / dist;
+			slope = (dest->Z() + self->height*2/3 - self->Z()) / dist;
 		}
 		if (slope < self->velz)
 		{
diff --git a/src/g_strife/a_stalker.cpp b/src/g_strife/a_stalker.cpp
index 258cbef3f..6a06bf867 100644
--- a/src/g_strife/a_stalker.cpp
+++ b/src/g_strife/a_stalker.cpp
@@ -17,7 +17,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_StalkerChaseDecide)
 	{
 		self->SetState (self->FindState("SeeFloor"));
 	}
-	else if (self->ceilingz - self->height > self->z)
+	else if (self->ceilingz > self->Top())
 	{
 		self->SetState (self->FindState("Drop"));
 	}
diff --git a/src/g_strife/a_strifestuff.cpp b/src/g_strife/a_strifestuff.cpp
index 9f3ebb272..3145290ef 100644
--- a/src/g_strife/a_strifestuff.cpp
+++ b/src/g_strife/a_strifestuff.cpp
@@ -580,7 +580,7 @@ IMPLEMENT_CLASS (AMeat)
 DEFINE_ACTION_FUNCTION(AActor, A_TossGib)
 {
 	const char *gibtype = (self->flags & MF_NOBLOOD) ? "Junk" : "Meat";
-	AActor *gib = Spawn (gibtype, self->x, self->y, self->z + 24*FRACUNIT, ALLOW_REPLACE);
+	AActor *gib = Spawn (gibtype, self->PosPlusZ(24*FRACUNIT), ALLOW_REPLACE);
 	angle_t an;
 	int speed;
 
@@ -628,7 +628,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_CheckTerrain)
 {
 	sector_t *sec = self->Sector;
 
-	if (self->z == sec->floorplane.ZatPoint(self))
+	if (self->Z() == sec->floorplane.ZatPoint(self))
 	{
 		if (sec->special == Damage_InstantDeath)
 		{
@@ -681,7 +681,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_ItBurnsItBurns)
 
 DEFINE_ACTION_FUNCTION(AActor, A_DropFire)
 {
-	AActor *drop = Spawn("FireDroplet", self->x, self->y, self->z + 24*FRACUNIT, ALLOW_REPLACE);
+	AActor *drop = Spawn("FireDroplet", self->PosPlusZ(24*FRACUNIT), ALLOW_REPLACE);
 	drop->velz = -FRACUNIT;
 	P_RadiusAttack (self, self, 64, 64, NAME_Fire, 0);
 }
diff --git a/src/g_strife/a_strifeweapons.cpp b/src/g_strife/a_strifeweapons.cpp
index f5d4a3576..a33521087 100644
--- a/src/g_strife/a_strifeweapons.cpp
+++ b/src/g_strife/a_strifeweapons.cpp
@@ -360,8 +360,8 @@ DEFINE_ACTION_FUNCTION(AActor, A_RocketInFlight)
 	AActor *trail;
 
 	S_Sound (self, CHAN_VOICE, "misc/missileinflight", 1, ATTN_NORM);
-	P_SpawnPuff (self, PClass::FindClass("MiniMissilePuff"), self->x, self->y, self->z, self->angle - ANGLE_180, 2, PF_HITTHING);
-	trail = Spawn("RocketTrail", self->x - self->velx, self->y - self->vely, self->z, ALLOW_REPLACE);
+	P_SpawnPuff (self, PClass::FindClass("MiniMissilePuff"), self->Pos(), self->angle - ANGLE_180, 2, PF_HITTHING);
+	trail = Spawn("RocketTrail", self->Vec3Offset(-self->velx, -self->vely, 0), ALLOW_REPLACE);
 	if (trail != NULL)
 	{
 		trail->velz = FRACUNIT;
@@ -516,10 +516,10 @@ DEFINE_ACTION_FUNCTION(AActor, A_MaulerTorpedoWave)
 	self->angle += ANGLE_180;
 
 	// If the torpedo hit the ceiling, it should still spawn the wave
-	savedz = self->z;
-	if (wavedef && self->ceilingz - self->z < wavedef->height)
+	savedz = self->Z();
+	if (wavedef && self->ceilingz - self->Z() < wavedef->height)
 	{
-		self->z = self->ceilingz - wavedef->height;
+		self->SetZ(self->ceilingz - wavedef->height);
 	}
 
 	for (int i = 0; i < 80; ++i)
@@ -527,12 +527,12 @@ DEFINE_ACTION_FUNCTION(AActor, A_MaulerTorpedoWave)
 		self->angle += ANGLE_45/10;
 		P_SpawnSubMissile (self, PClass::FindClass("MaulerTorpedoWave"), self->target);
 	}
-	self->z = savedz;
+	self->SetZ(savedz);
 }
 
 AActor *P_SpawnSubMissile (AActor *source, const PClass *type, AActor *target)
 {
-	AActor *other = Spawn (type, source->x, source->y, source->z, ALLOW_REPLACE);
+	AActor *other = Spawn (type, source->Pos(), ALLOW_REPLACE);
 
 	if (other == NULL)
 	{
@@ -619,20 +619,19 @@ DEFINE_ACTION_FUNCTION(AActor, A_Burnination)
 			yofs = -yofs;
 		}
 
-		fixed_t x = self->x + (xofs << FRACBITS);
-		fixed_t y = self->y + (yofs << FRACBITS);
-		sector_t * sector = P_PointInSector(x, y);
+		fixedvec2 pos = self->Vec2Offset(xofs << FRACBITS, yofs << FRACBITS);
+		sector_t * sector = P_PointInSector(pos.x, pos.y);
 
 		// The sector's floor is too high so spawn the flame elsewhere.
-		if (sector->floorplane.ZatPoint(x, y) > self->z + self->MaxStepHeight)
+		if (sector->floorplane.ZatPoint(pos.x, pos.y) > self->Z() + self->MaxStepHeight)
 		{
-			x = self->x;
-			y = self->y;
+			pos.x = self->X();
+			pos.y = self->Y();
 		}
 
 		AActor *drop = Spawn<APhosphorousFire> (
-			x, y,
-			self->z + 4*FRACUNIT, ALLOW_REPLACE);
+			pos.x, pos.y,
+			self->Z() + 4*FRACUNIT, ALLOW_REPLACE);
 		if (drop != NULL)
 		{
 			drop->velx = self->velx + ((pr_phburn.Random2 (7)) << FRACBITS);
@@ -677,9 +676,9 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_FireGrenade)
 
 	if (grenadetype != NULL)
 	{
-		self->z += 32*FRACUNIT;
+		self->AddZ(32*FRACUNIT);
 		grenade = P_SpawnSubMissile (self, grenadetype, self);
-		self->z -= 32*FRACUNIT;
+		self->AddZ(-32*FRACUNIT);
 		if (grenade == NULL)
 			return;
 
@@ -690,15 +689,20 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_FireGrenade)
 
 		grenade->velz = FixedMul (finetangent[FINEANGLES/4-(self->pitch>>ANGLETOFINESHIFT)], grenade->Speed) + 8*FRACUNIT;
 
+		fixedvec2 offset;
+
 		an = self->angle >> ANGLETOFINESHIFT;
 		tworadii = self->radius + grenade->radius;
-		grenade->x += FixedMul (finecosine[an], tworadii);
-		grenade->y += FixedMul (finesine[an], tworadii);
+		offset.x = FixedMul (finecosine[an], tworadii);
+		offset.y = FixedMul (finesine[an], tworadii);
 
 		an = self->angle + Angle;
 		an >>= ANGLETOFINESHIFT;
-		grenade->x += FixedMul (finecosine[an], 15*FRACUNIT);
-		grenade->y += FixedMul (finesine[an], 15*FRACUNIT);
+		offset.x += FixedMul (finecosine[an], 15*FRACUNIT);
+		offset.y += FixedMul (finesine[an], 15*FRACUNIT);
+
+		fixedvec2 newpos = grenade->Vec2Offset(offset.x, offset.y);
+		grenade->SetOrigin(newpos.x, newpos.y, grenade->Z(), false);
 	}
 }
 
@@ -923,7 +927,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_FireSigil1)
 	P_BulletSlope (self, &linetarget);
 	if (linetarget != NULL)
 	{
-		spot = Spawn("SpectralLightningSpot", linetarget->x, linetarget->y, linetarget->floorz, ALLOW_REPLACE);
+		spot = Spawn("SpectralLightningSpot", linetarget->X(), linetarget->Y(), linetarget->floorz, ALLOW_REPLACE);
 		if (spot != NULL)
 		{
 			spot->tracer = linetarget;
@@ -931,7 +935,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_FireSigil1)
 	}
 	else
 	{
-		spot = Spawn("SpectralLightningSpot", self->x, self->y, self->z, ALLOW_REPLACE);
+		spot = Spawn("SpectralLightningSpot", self->Pos(), ALLOW_REPLACE);
 		if (spot != NULL)
 		{
 			spot->velx += 28 * finecosine[self->angle >> ANGLETOFINESHIFT];
@@ -989,7 +993,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_FireSigil3)
 		spot = P_SpawnSubMissile (self, PClass::FindClass("SpectralLightningBall1"), self);
 		if (spot != NULL)
 		{
-			spot->z = self->z + 32*FRACUNIT;
+			spot->SetZ(self->Z() + 32*FRACUNIT);
 		}
 	}
 	self->angle -= (ANGLE_180/20)*10;
diff --git a/src/g_strife/a_thingstoblowup.cpp b/src/g_strife/a_thingstoblowup.cpp
index d27260451..86ae7282e 100644
--- a/src/g_strife/a_thingstoblowup.cpp
+++ b/src/g_strife/a_thingstoblowup.cpp
@@ -20,10 +20,9 @@ DEFINE_ACTION_FUNCTION(AActor, A_Bang4Cloud)
 {
 	fixed_t spawnx, spawny;
 
-	spawnx = self->x + (pr_bang4cloud.Random2() & 3) * 10240;
-	spawny = self->y + (pr_bang4cloud.Random2() & 3) * 10240;
+	fixedvec3 pos = self->Vec3Offset((pr_bang4cloud.Random2() & 3) * 10240, (pr_bang4cloud.Random2() & 3) * 10240, 0);
 
-	Spawn("Bang4Cloud", spawnx, spawny, self->z, ALLOW_REPLACE);
+	Spawn("Bang4Cloud", pos, ALLOW_REPLACE);
 }
 
 // -------------------------------------------------------------------
@@ -97,7 +96,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_LightGoesOut)
 
 	for (int i = 0; i < 8; ++i)
 	{
-		foo = Spawn("Rubble1", self->x, self->y, self->z, ALLOW_REPLACE);
+		foo = Spawn("Rubble1", self->Pos(), ALLOW_REPLACE);
 		if (foo != NULL)
 		{
 			int t = pr_lightout() & 15;
diff --git a/src/p_writemap.cpp b/src/p_writemap.cpp
index e31d2c4c3..8f1a4edfa 100644
--- a/src/p_writemap.cpp
+++ b/src/p_writemap.cpp
@@ -98,8 +98,8 @@ static int WriteTHINGS (FILE *file)
 	mapthinghexen_t mt = { 0, 0, 0, 0, 0, 0, 0, 0, {0} };
 	AActor *mo = players[consoleplayer].mo;
 
-	mt.x = LittleShort(short(mo->x >> FRACBITS));
-	mt.y = LittleShort(short(mo->y >> FRACBITS));
+	mt.x = LittleShort(short(mo->X() >> FRACBITS));
+	mt.y = LittleShort(short(mo->Y() >> FRACBITS));
 	mt.angle = LittleShort(short(MulScale32 (mo->angle >> ANGLETOFINESHIFT, 360)));
 	mt.type = LittleShort((short)1);
 	mt.flags = LittleShort((short)(7|224|MTF_SINGLE));
diff --git a/src/r_plane.cpp b/src/r_plane.cpp
index 96a77930a..84967c164 100644
--- a/src/r_plane.cpp
+++ b/src/r_plane.cpp
@@ -1224,9 +1224,10 @@ void R_DrawSkyBoxes ()
 			extralight = 0;
 			R_SetVisibility (sky->args[0] * 0.25f);
 
-			viewx = sky->PrevX + FixedMul(r_TicFrac, sky->x - sky->PrevX);
-			viewy = sky->PrevY + FixedMul(r_TicFrac, sky->y - sky->PrevY);
-			viewz = sky->PrevZ + FixedMul(r_TicFrac, sky->z - sky->PrevZ);
+			fixedvec3 viewpos = sky->InterpolatedPosition(r_TicFrac);
+			viewx = viewpos.x;
+			viewy = viewpos.y;
+			viewz = viewpos.z;
 			viewangle = savedangle + sky->PrevAngle + FixedMul(r_TicFrac, sky->angle - sky->PrevAngle);
 
 			R_CopyStackedViewParameters();
@@ -1235,8 +1236,8 @@ void R_DrawSkyBoxes ()
 		{
 			extralight = pl->extralight;
 			R_SetVisibility (pl->visibility);
-			viewx = pl->viewx - sky->Mate->x + sky->x;
-			viewy = pl->viewy - sky->Mate->y + sky->y;
+			viewx = pl->viewx - sky->Mate->X() + sky->X();
+			viewy = pl->viewy - sky->Mate->Y() + sky->Y();
 			viewz = pl->viewz;
 			viewangle = pl->viewangle;
 		}
diff --git a/src/r_things.cpp b/src/r_things.cpp
index 8e53fb6d1..8ad5f76a9 100644
--- a/src/r_things.cpp
+++ b/src/r_things.cpp
@@ -670,9 +670,10 @@ void R_ProjectSprite (AActor *thing, int fakeside, F3DFloor *fakefloor, F3DFloor
 	}
 
 	// [RH] Interpolate the sprite's position to make it look smooth
-	fx = thing->PrevX + FixedMul (r_TicFrac, thing->x - thing->PrevX);
-	fy = thing->PrevY + FixedMul (r_TicFrac, thing->y - thing->PrevY);
-	fz = thing->PrevZ + FixedMul (r_TicFrac, thing->z - thing->PrevZ) + thing->GetBobOffset(r_TicFrac);
+	fixedvec3 pos = thing->InterpolatedPosition(r_TicFrac);
+	fx = pos.x;
+	fy = pos.y;
+	fz = pos.z +thing->GetBobOffset(r_TicFrac);
 
 	tex = NULL;
 	voxel = NULL;
@@ -1145,12 +1146,12 @@ void R_AddSprites (sector_t *sec, int lightlevel, int fakeside)
 			{
 				if(!(rover->top.plane->a) && !(rover->top.plane->b))
 				{
-					if(rover->top.plane->Zat0() <= thing->z) fakefloor = rover;
+					if(rover->top.plane->Zat0() <= thing->Z()) fakefloor = rover;
 				}
 			}
 			if(!(rover->bottom.plane->a) && !(rover->bottom.plane->b))
 			{
-				if(rover->bottom.plane->Zat0() >= thing->z + thing->height) fakeceiling = rover;
+				if(rover->bottom.plane->Zat0() >= thing->Top()) fakeceiling = rover;
 			}
 		}	
 		R_ProjectSprite (thing, fakeside, fakefloor, fakeceiling);
diff --git a/src/r_utility.cpp b/src/r_utility.cpp
index cfe1767c7..d4d3ec97b 100644
--- a/src/r_utility.cpp
+++ b/src/r_utility.cpp
@@ -587,8 +587,8 @@ void R_InterpolateView (player_t *player, fixed_t frac, InterpolationViewer *ivi
 		player - players == consoleplayer &&
 		camera == player->mo &&
 		!demoplayback &&
-		iview->nviewx == camera->x &&
-		iview->nviewy == camera->y && 
+		iview->nviewx == camera->X() &&
+		iview->nviewy == camera->Y() && 
 		!(player->cheats & (CF_TOTALLYFROZEN|CF_FROZEN)) &&
 		player->playerstate == PST_LIVE &&
 		player->mo->reactiontime == 0 &&
@@ -839,9 +839,9 @@ void R_SetupFrame (AActor *actor)
 	}
 	else
 	{
-		iview->nviewx = camera->x;
-		iview->nviewy = camera->y;
-		iview->nviewz = camera->player ? camera->player->viewz : camera->z + camera->GetClass()->Meta.GetMetaFixed(AMETA_CameraHeight);
+		iview->nviewx = camera->X();
+		iview->nviewy = camera->Y();
+		iview->nviewz = camera->player ? camera->player->viewz : camera->Z() + camera->GetClass()->Meta.GetMetaFixed(AMETA_CameraHeight);
 		viewsector = camera->Sector;
 		r_showviewer = false;
 	}