diff --git a/src/control/Replay.cpp b/src/control/Replay.cpp
index 06995663..d0264415 100644
--- a/src/control/Replay.cpp
+++ b/src/control/Replay.cpp
@@ -686,8 +686,8 @@ void CReplay::ProcessCarUpdate(CVehicle *vehicle, float interpolation, CAddressI
 			car->m_aSuspensionSpringRatio[i] = vp->wheel_susp_dist[i] / 50.0f;
 			car->m_aWheelRotation[i] = vp->wheel_rotation[i] * M_PI / 128.0f;
 		}
-		car->Doors[2].m_fAngle = car->Doors[2].m_fPreviousAngle = vp->door_angles[0] * M_PI / 127.0f;
-		car->Doors[3].m_fAngle = car->Doors[3].m_fPreviousAngle = vp->door_angles[1] * M_PI / 127.0f;
+		car->Doors[2].m_fAngle = car->Doors[2].m_fPrevAngle = vp->door_angles[0] * M_PI / 127.0f;
+		car->Doors[3].m_fAngle = car->Doors[3].m_fPrevAngle = vp->door_angles[1] * M_PI / 127.0f;
 		if (vp->door_angles[0])
 			car->Damage.SetDoorStatus(2, 2);
 		if (vp->door_angles[1])
diff --git a/src/math/Matrix.h b/src/math/Matrix.h
index 6e1001cb..5cc7d12f 100644
--- a/src/math/Matrix.h
+++ b/src/math/Matrix.h
@@ -306,6 +306,15 @@ Multiply3x3(const CMatrix &mat, const CVector &vec)
 		mat.m_matrix.right.z * vec.x + mat.m_matrix.up.z * vec.y + mat.m_matrix.at.z * vec.z);
 }
 
+inline CVector
+Multiply3x3(const CVector &vec, const CMatrix &mat)
+{
+	return CVector(
+		mat.m_matrix.right.x * vec.x + mat.m_matrix.right.y * vec.y + mat.m_matrix.right.z * vec.z,
+		mat.m_matrix.up.x * vec.x + mat.m_matrix.up.y * vec.y + mat.m_matrix.up.z * vec.z,
+		mat.m_matrix.at.x * vec.x + mat.m_matrix.at.y * vec.y + mat.m_matrix.at.z * vec.z);
+}
+
 class CCompressedMatrixNotAligned
 {
 	CVector m_vecPos;
diff --git a/src/vehicles/Automobile.cpp b/src/vehicles/Automobile.cpp
index 54eed17a..80131179 100644
--- a/src/vehicles/Automobile.cpp
+++ b/src/vehicles/Automobile.cpp
@@ -14,5 +14,5 @@ WRAPPER void CAutomobile::SetPanelDamage(int32, uint32, bool) { EAXJMP(0x5301A0)
 WRAPPER void CAutomobile::SetBumperDamage(int32, uint32, bool) { EAXJMP(0x530120); }
 
 STARTPATCHES
-InjectHook(0x52D170, &CAutomobile::dtor, PATCH_JUMP);
-ENDPATCHES
\ No newline at end of file
+	InjectHook(0x52D170, &CAutomobile::dtor, PATCH_JUMP);
+ENDPATCHES
diff --git a/src/vehicles/Automobile.h b/src/vehicles/Automobile.h
index 630635c7..c20d078b 100644
--- a/src/vehicles/Automobile.h
+++ b/src/vehicles/Automobile.h
@@ -1,21 +1,8 @@
 #pragma once
 
-#include "DamageManager.h"
 #include "Vehicle.h"
-
-struct CDoor
-{
-	float m_fAngleWhenOpened;
-	float m_fAngleWhenClosed;
-	char field_8;
-	char field_9;
-	char field_10;
-	char field_11;
-	float m_fAngle;
-	float m_fPreviousAngle;
-	float m_fAngularVelocity;
-	CVector m_vecVelocity;
-};
+#include "DamageManager.h"
+#include "Door.h"
 
 class CAutomobile : public CVehicle
 {
diff --git a/src/vehicles/Door.cpp b/src/vehicles/Door.cpp
new file mode 100644
index 00000000..ec5eb223
--- /dev/null
+++ b/src/vehicles/Door.cpp
@@ -0,0 +1,126 @@
+#include "common.h"
+#include "patcher.h"
+#include "Vehicle.h"
+#include "Door.h"
+
+CDoor::CDoor(void)
+{
+	memset(this, 0, sizeof(*this));
+}
+
+void
+CDoor::Open(float ratio)
+{
+	float open;
+
+	m_fPrevAngle = m_fAngle;
+	open = RetAngleWhenOpen();
+	if(ratio < 1.0f){
+		m_fAngle = open*ratio;
+		if(m_fAngle == 0.0f)
+			m_fAngVel = 0.0f;
+	}else{
+		m_nDoorState = DOORST_OPEN;
+		m_fAngle = open;
+	}
+}
+
+void
+CDoor::Process(CVehicle *vehicle)
+{
+	static CVector vecOffset(1.0f, 0.0f, 0.0f);
+	CVector speed = vehicle->GetSpeed(vecOffset);
+	CVector vecSpeedDiff = speed - m_vecSpeed;
+	vecSpeedDiff = Multiply3x3(vecSpeedDiff, vehicle->GetMatrix());
+
+	// air resistance
+	float fSpeedDiff = 0.0f;	// uninitialized in game
+	switch(m_nAxis){
+	case 0:	// x-axis
+		if(m_nDirn)
+			fSpeedDiff = vecSpeedDiff.y + vecSpeedDiff.z;
+		else
+			fSpeedDiff = -(vecSpeedDiff.y + vecSpeedDiff.z);
+		break;
+
+	// we don't support y axis apparently?
+
+	case 2:	// z-axis
+		if(m_nDirn)
+			fSpeedDiff = -(vecSpeedDiff.x + vecSpeedDiff.y);
+		else
+			fSpeedDiff = vecSpeedDiff.x + vecSpeedDiff.y;
+		break;
+	}
+	fSpeedDiff = clamp(fSpeedDiff, -0.2f, 0.2f);
+	if(fabs(fSpeedDiff) > 0.002f)
+		m_fAngVel += fSpeedDiff;
+	m_fAngVel *= 0.945f;
+	m_fAngVel = clamp(m_fAngVel, -0.3f, 0.3f);
+
+	m_fAngle += m_fAngVel;
+	m_nDoorState = DOORST_SWINGING;
+	if(m_fAngle > m_fMaxAngle){
+		m_fAngle = m_fMaxAngle;
+		m_fAngVel *= -0.8f;
+		m_nDoorState = DOORST_OPEN;
+	}
+	if(m_fAngle < m_fMinAngle){
+		m_fAngle = m_fMinAngle;
+		m_fAngVel *= -0.8f;
+		m_nDoorState = DOORST_CLOSED;
+	}
+	m_vecSpeed = speed;
+}
+
+float
+CDoor::RetAngleWhenClosed(void)
+{
+	if(fabs(m_fMaxAngle) < fabs(m_fMinAngle))
+		return m_fMaxAngle;
+	else
+		return m_fMinAngle;
+}
+
+float
+CDoor::RetAngleWhenOpen(void)
+{
+	if(fabs(m_fMaxAngle) < fabs(m_fMinAngle))
+		return m_fMinAngle;
+	else
+		return m_fMaxAngle;
+}
+
+float
+CDoor::GetAngleOpenRatio(void)
+{
+	float open = RetAngleWhenOpen();
+	if(open == 0.0f)
+		return 0.0f;
+	return m_fAngle/open;
+}
+
+bool
+CDoor::IsFullyOpen(void)
+{
+	// why -0.5? that's around 28 deg less than fully open
+	if(fabs(m_fAngle) < fabs(RetAngleWhenOpen()) - 0.5f)
+		return false;
+	return true;
+}
+
+bool
+CDoor::IsClosed(void)
+{
+	return m_fAngle == RetAngleWhenClosed();
+}
+
+STARTPATCHES
+	InjectHook(0x545EF0, &CDoor::Open, PATCH_JUMP);
+	InjectHook(0x545BD0, &CDoor::Process, PATCH_JUMP);
+	InjectHook(0x545FE0, &CDoor::RetAngleWhenClosed, PATCH_JUMP);
+	InjectHook(0x546020, &CDoor::RetAngleWhenOpen, PATCH_JUMP);
+	InjectHook(0x545F80, &CDoor::GetAngleOpenRatio, PATCH_JUMP);
+	InjectHook(0x546090, &CDoor::IsFullyOpen, PATCH_JUMP);
+	InjectHook(0x546060, &CDoor::IsClosed, PATCH_JUMP);
+ENDPATCHES
diff --git a/src/vehicles/Door.h b/src/vehicles/Door.h
new file mode 100644
index 00000000..fc771a40
--- /dev/null
+++ b/src/vehicles/Door.h
@@ -0,0 +1,36 @@
+#pragma once
+
+class CVehicle;
+
+enum eDoorState
+{
+	DOORST_SWINGING,
+	// actually wrong though,
+	// OPEN is really MAX_ANGLE and CLOSED is MIN_ANGLE
+	DOORST_OPEN,
+	DOORST_CLOSED
+};
+
+struct CDoor
+{
+	float m_fMaxAngle;
+	float m_fMinAngle;
+	// direction of rotation for air resistance
+	int8 m_nDirn;
+	// axis in which this door rotates
+	int8 m_nAxis;
+	int8 m_nDoorState;
+	float m_fAngle;
+	float m_fPrevAngle;
+	float m_fAngVel;
+	CVector m_vecSpeed;
+
+	CDoor(void);
+	void Open(float ratio);
+	void Process(CVehicle *veh);
+	float RetAngleWhenClosed(void);
+	float RetAngleWhenOpen(void);
+	float GetAngleOpenRatio(void);
+	bool IsFullyOpen(void);
+	bool IsClosed(void);
+};