diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 4956a43628..e17e6ddfba 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,4 +1,5 @@
 June 30, 2009
+- Added A_SetAngle, A_SetPitch, A_ScaleVelocity, and A_ChangeVelocity.
 - Enough with this "momentum" garbage. What Doom calls "momentum" is really
   velocity, and now it's known as such. The actor variables momx/momy/momz
   are now known as velx/vely/velz, and the ACS functions GetActorMomX/Y/Z
diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index 67f11a1010..1f09dc94f7 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -2533,7 +2533,9 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_RemoveChildren)
 
 //===========================================================================
 //
-// keep firing unless target got out of sight
+// A_MonsterRefire
+//
+// Keep firing unless target got out of sight
 //
 //===========================================================================
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_MonsterRefire)
@@ -2557,3 +2559,101 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_MonsterRefire)
 	}
 }
 
+//===========================================================================
+//
+// A_SetAngle
+//
+// Set actor's angle (in degrees).
+//
+//===========================================================================
+
+DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_SetAngle)
+{
+	ACTION_PARAM_START(1);
+	ACTION_PARAM_ANGLE(angle, 0);
+	self->angle = angle;
+}
+
+//===========================================================================
+//
+// A_SetPitch
+//
+// Set actor's pitch (in degrees).
+//
+//===========================================================================
+
+DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_SetPitch)
+{
+	ACTION_PARAM_START(1);
+	ACTION_PARAM_ANGLE(pitch, 0);
+	self->pitch = pitch;
+}
+
+//===========================================================================
+//
+// A_ScaleVelocity
+//
+// Scale actor's velocity.
+//
+//===========================================================================
+
+DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_ScaleVelocity)
+{
+	ACTION_PARAM_START(1);
+	ACTION_PARAM_FIXED(scale, 0);
+
+	INTBOOL was_moving = self->velx | self->vely | self->velz;
+
+	self->velx = FixedMul(self->velx, scale);
+	self->vely = FixedMul(self->vely, scale);
+	self->velz = FixedMul(self->velz, scale);
+
+	// If the actor was previously moving but now is not, and is a player,
+	// update its player variables. (See A_Stop.)
+	if (was_moving &&
+		self->player != NULL &&
+		self->player->mo == self &&
+		!(self->player->cheats & CF_PREDICTING) &&
+		!(self->velx | self->vely | self->velz))
+	{
+		self->player->mo->PlayIdle();
+		self->player->velx = self->player->vely = 0;
+	}
+}
+
+//===========================================================================
+//
+// A_ChangeVelocity
+//
+//===========================================================================
+
+DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_ChangeVelocity)
+{
+	ACTION_PARAM_START(4);
+	ACTION_PARAM_FIXED(x, 0);
+	ACTION_PARAM_FIXED(y, 1);
+	ACTION_PARAM_FIXED(z, 2);
+	ACTION_PARAM_INT(flags, 3);
+
+	fixed_t vx = x, vy = y, vz = z;
+	fixed_t sina = finesine[self->angle >> ANGLETOFINESHIFT];
+	fixed_t cosa = finecosine[self->angle >> ANGLETOFINESHIFT];
+
+	if (flags & 1)	// relative axes - make x, y relative to actor's current angle
+	{
+		vx = DMulScale16(x, cosa, -y, sina);
+		vy = DMulScale16(x, sina,  y, cosa);
+	}
+	if (flags & 2)	// discard old velocity - replace old velocity with new velocity
+	{
+		self->velx = vx;
+		self->vely = vy;
+		self->velz = vz;
+	}
+	else	// add new velocity to old velocity
+	{
+		self->velx += vx;
+		self->vely += vy;
+		self->velz += vz;
+	}
+}
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index dcd3c1fa63..fde7daf414 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -241,6 +241,10 @@ ACTOR Actor native //: Thinker
 	action native A_DropWeaponPieces(class<Actor> p1, class<Actor> p2, class<Actor> p3);
 	action native A_PigPain ();
 	action native A_MonsterRefire(int chance, state label);
+	action native A_SetAngle(float angle);
+	action native A_SetPitch(float pitch);
+	action native A_ScaleVelocity(float scale);
+	action native A_ChangeVelocity(float x = 0, float y = 0, float z = 0, int flags = 0);
 
 	States
 	{
diff --git a/wadsrc/static/actors/constants.txt b/wadsrc/static/actors/constants.txt
index 3883446181..fb81d297e0 100644
--- a/wadsrc/static/actors/constants.txt
+++ b/wadsrc/static/actors/constants.txt
@@ -33,6 +33,10 @@ const int LOF_DONTCHASEGOAL = 4;
 const int LOF_NOSEESOUND = 8;
 const int LOF_FULLVOLSEESOUND = 16;
 
+// Flags for A_ChangeVelocity
+const int CVF_RELATIVE = 1;
+const int CVF_REPLACE = 2;
+
 // Morph constants
 const int MRF_ADDSTAMINA = 1;
 const int MRF_FULLHEALTH = 2;