diff --git a/irr/include/vector3d.h b/irr/include/vector3d.h
index a69f17e16..31dfd6955 100644
--- a/irr/include/vector3d.h
+++ b/irr/include/vector3d.h
@@ -7,6 +7,7 @@
 #include "irrMath.h"
 
 #include <functional>
+#include <array>
 
 namespace irr
 {
@@ -32,6 +33,9 @@ class vector3d
 	//! Constructor with the same value for all elements
 	explicit constexpr vector3d(T n) :
 			X(n), Y(n), Z(n) {}
+	//! Array - vector conversion
+	constexpr vector3d(const std::array<T, 3> &arr) :
+			X(arr[0]), Y(arr[1]), Z(arr[2]) {}
 
 	// operators
 
@@ -181,6 +185,10 @@ class vector3d
 		return *this;
 	}
 
+	std::array<T, 3> toArray() const {
+		return {X, Y, Z};
+	}
+
 	//! Get length of the vector.
 	T getLength() const { return core::squareroot(X * X + Y * Y + Z * Z); }
 
diff --git a/src/server/activeobjectmgr.cpp b/src/server/activeobjectmgr.cpp
index 983fc0d95..e11ba166e 100644
--- a/src/server/activeobjectmgr.cpp
+++ b/src/server/activeobjectmgr.cpp
@@ -83,16 +83,17 @@ bool ActiveObjectMgr::registerObject(std::unique_ptr<ServerActiveObject> obj)
 		return false;
 	}
 
-	if (objectpos_over_limit(obj->getBasePosition())) {
-		v3f p = obj->getBasePosition();
+	const v3f pos = obj->getBasePosition();
+	if (objectpos_over_limit(pos)) {
 		warningstream << "Server::ActiveObjectMgr::addActiveObjectRaw(): "
-				<< "object position (" << p.X << "," << p.Y << "," << p.Z
+				<< "object position (" << pos.X << "," << pos.Y << "," << pos.Z
 				<< ") outside maximum range" << std::endl;
 		return false;
 	}
 
 	auto obj_id = obj->getId(); 
 	m_active_objects.put(obj_id, std::move(obj));
+	m_spatial_index.insert(pos.toArray(), obj_id);
 
 	auto new_size = m_active_objects.size();
 	verbosestream << "Server::ActiveObjectMgr::addActiveObjectRaw(): "
@@ -115,42 +116,45 @@ void ActiveObjectMgr::removeObject(u16 id)
 	if (!ok) {
 		infostream << "Server::ActiveObjectMgr::removeObject(): "
 				<< "id=" << id << " not found" << std::endl;
+	} else {
+		m_spatial_index.remove(id);
 	}
 }
 
+void ActiveObjectMgr::updatePos(const v3f &pos, u16 id) {
+	// laziggy solution: only update if we already know the object
+	if (m_active_objects.get(id) != nullptr)
+		m_spatial_index.update(pos.toArray(), id);
+}
+
 void ActiveObjectMgr::getObjectsInsideRadius(const v3f &pos, float radius,
 		std::vector<ServerActiveObject *> &result,
 		std::function<bool(ServerActiveObject *obj)> include_obj_cb)
 {
-	float r2 = radius * radius;
-	for (auto &activeObject : m_active_objects.iter()) {
-		ServerActiveObject *obj = activeObject.second.get();
-		if (!obj)
-			continue;
-		const v3f &objectpos = obj->getBasePosition();
-		if (objectpos.getDistanceFromSQ(pos) > r2)
-			continue;
+	float r_squared = radius * radius;
+	m_spatial_index.rangeQuery((pos - v3f(radius)).toArray(), (pos + v3f(radius)).toArray(), [&](auto objPos, u16 id) {
+		if (v3f(objPos).getDistanceFromSQ(pos) > r_squared)
+			return;
 
+		auto obj = m_active_objects.get(id).get();
+		if (!obj)
+			return;
 		if (!include_obj_cb || include_obj_cb(obj))
 			result.push_back(obj);
-	}
+	});
 }
 
 void ActiveObjectMgr::getObjectsInArea(const aabb3f &box,
 		std::vector<ServerActiveObject *> &result,
 		std::function<bool(ServerActiveObject *obj)> include_obj_cb)
 {
-	for (auto &activeObject : m_active_objects.iter()) {
-		ServerActiveObject *obj = activeObject.second.get();
+	m_spatial_index.rangeQuery(box.MinEdge.toArray(), box.MaxEdge.toArray(), [&](auto _, u16 id) {
+		auto obj = m_active_objects.get(id).get();
 		if (!obj)
-			continue;
-		const v3f &objectpos = obj->getBasePosition();
-		if (!box.isPointInside(objectpos))
-			continue;
-
+			return;
 		if (!include_obj_cb || include_obj_cb(obj))
 			result.push_back(obj);
-	}
+	});
 }
 
 void ActiveObjectMgr::getAddedActiveObjectsAroundPos(v3f player_pos, f32 radius,
diff --git a/src/server/activeobjectmgr.h b/src/server/activeobjectmgr.h
index dab795e8c..5e524dedb 100644
--- a/src/server/activeobjectmgr.h
+++ b/src/server/activeobjectmgr.h
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <vector>
 #include "../activeobjectmgr.h"
 #include "serveractiveobject.h"
+#include "util/k_d_tree.h"
 
 namespace server
 {
@@ -38,6 +39,8 @@ class ActiveObjectMgr final : public ::ActiveObjectMgr<ServerActiveObject>
 	bool registerObject(std::unique_ptr<ServerActiveObject> obj) override;
 	void removeObject(u16 id) override;
 
+	void updatePos(const v3f &pos, u16 id);
+
 	void getObjectsInsideRadius(const v3f &pos, float radius,
 			std::vector<ServerActiveObject *> &result,
 			std::function<bool(ServerActiveObject *obj)> include_obj_cb);
@@ -48,5 +51,7 @@ class ActiveObjectMgr final : public ::ActiveObjectMgr<ServerActiveObject>
 	void getAddedActiveObjectsAroundPos(v3f player_pos, f32 radius,
 			f32 player_radius, const std::set<u16> &current_objects,
 			std::vector<u16> &added_objects);
+private:
+	DynamicKdTrees<3, f32, u16> m_spatial_index;
 };
 } // namespace server
diff --git a/src/server/luaentity_sao.cpp b/src/server/luaentity_sao.cpp
index 020f13fa5..12026e1cf 100644
--- a/src/server/luaentity_sao.cpp
+++ b/src/server/luaentity_sao.cpp
@@ -162,7 +162,7 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 	// Each frame, parent position is copied if the object is attached, otherwise it's calculated normally
 	// If the object gets detached this comes into effect automatically from the last known origin
 	if (auto *parent = getParent()) {
-		m_base_position = parent->getBasePosition();
+		setBasePosition(parent->getBasePosition());
 		m_velocity = v3f(0,0,0);
 		m_acceleration = v3f(0,0,0);
 	} else {
@@ -171,7 +171,7 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 			box.MinEdge *= BS;
 			box.MaxEdge *= BS;
 			f32 pos_max_d = BS*0.25; // Distance per iteration
-			v3f p_pos = m_base_position;
+			v3f p_pos = getBasePosition();
 			v3f p_velocity = m_velocity;
 			v3f p_acceleration = m_acceleration;
 			moveresult = collisionMoveSimple(m_env, m_env->getGameDef(),
@@ -181,11 +181,11 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 			moveresult_p = &moveresult;
 
 			// Apply results
-			m_base_position = p_pos;
+			setBasePosition(p_pos);
 			m_velocity = p_velocity;
 			m_acceleration = p_acceleration;
 		} else {
-			m_base_position += (m_velocity + m_acceleration * 0.5f * dtime) * dtime;
+			addPos((m_velocity + m_acceleration * 0.5f * dtime) * dtime);
 			m_velocity += dtime * m_acceleration;
 		}
 
@@ -228,7 +228,7 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 		} else if(m_last_sent_position_timer > 0.2){
 			minchange = 0.05*BS;
 		}
-		float move_d = m_base_position.getDistanceFrom(m_last_sent_position);
+		float move_d = getBasePosition().getDistanceFrom(m_last_sent_position);
 		move_d += m_last_sent_move_precision;
 		float vel_d = m_velocity.getDistanceFrom(m_last_sent_velocity);
 		if (move_d > minchange || vel_d > minchange ||
@@ -252,7 +252,7 @@ std::string LuaEntitySAO::getClientInitializationData(u16 protocol_version)
 	os << serializeString16(m_init_name); // name
 	writeU8(os, 0); // is_player
 	writeU16(os, getId()); //id
-	writeV3F32(os, m_base_position);
+	writeV3F32(os, getBasePosition());
 	writeV3F32(os, m_rotation);
 	writeU16(os, m_hp);
 
@@ -381,7 +381,7 @@ void LuaEntitySAO::setPos(const v3f &pos)
 {
 	if(isAttached())
 		return;
-	m_base_position = pos;
+	setBasePosition(pos);
 	sendPosition(false, true);
 }
 
@@ -389,7 +389,7 @@ void LuaEntitySAO::moveTo(v3f pos, bool continuous)
 {
 	if(isAttached())
 		return;
-	m_base_position = pos;
+	setBasePosition(pos);
 	if(!continuous)
 		sendPosition(true, true);
 }
@@ -403,7 +403,7 @@ std::string LuaEntitySAO::getDescription()
 {
 	std::ostringstream oss;
 	oss << "LuaEntitySAO \"" << m_init_name << "\" ";
-	auto pos = floatToInt(m_base_position, BS);
+	auto pos = floatToInt(getBasePosition(), BS);
 	oss << "at " << pos;
 	return oss.str();
 }
@@ -521,10 +521,10 @@ void LuaEntitySAO::sendPosition(bool do_interpolate, bool is_movement_end)
 	// Send attachment updates instantly to the client prior updating position
 	sendOutdatedData();
 
-	m_last_sent_move_precision = m_base_position.getDistanceFrom(
+	m_last_sent_move_precision = getBasePosition().getDistanceFrom(
 			m_last_sent_position);
 	m_last_sent_position_timer = 0;
-	m_last_sent_position = m_base_position;
+	m_last_sent_position = getBasePosition();
 	m_last_sent_velocity = m_velocity;
 	//m_last_sent_acceleration = m_acceleration;
 	m_last_sent_rotation = m_rotation;
@@ -532,7 +532,7 @@ void LuaEntitySAO::sendPosition(bool do_interpolate, bool is_movement_end)
 	float update_interval = m_env->getSendRecommendedInterval();
 
 	std::string str = generateUpdatePositionCommand(
-		m_base_position,
+		getBasePosition(),
 		m_velocity,
 		m_acceleration,
 		m_rotation,
@@ -552,8 +552,8 @@ bool LuaEntitySAO::getCollisionBox(aabb3f *toset) const
 		toset->MinEdge = m_prop.collisionbox.MinEdge * BS;
 		toset->MaxEdge = m_prop.collisionbox.MaxEdge * BS;
 
-		toset->MinEdge += m_base_position;
-		toset->MaxEdge += m_base_position;
+		toset->MinEdge += getBasePosition();
+		toset->MaxEdge += getBasePosition();
 
 		return true;
 	}
diff --git a/src/server/player_sao.cpp b/src/server/player_sao.cpp
index b2e2351c9..9357ce244 100644
--- a/src/server/player_sao.cpp
+++ b/src/server/player_sao.cpp
@@ -86,11 +86,10 @@ std::string PlayerSAO::getDescription()
 void PlayerSAO::addedToEnvironment(u32 dtime_s)
 {
 	ServerActiveObject::addedToEnvironment(dtime_s);
-	ServerActiveObject::setBasePosition(m_base_position);
 	m_player->setPlayerSAO(this);
 	m_player->setPeerId(m_peer_id_initial);
 	m_peer_id_initial = PEER_ID_INEXISTENT; // don't try to use it again.
-	m_last_good_position = m_base_position;
+	m_last_good_position = getBasePosition();
 }
 
 // Called before removing from environment
@@ -116,7 +115,7 @@ std::string PlayerSAO::getClientInitializationData(u16 protocol_version)
 	os << serializeString16(m_player->getName()); // name
 	writeU8(os, 1); // is_player
 	writeS16(os, getId()); // id
-	writeV3F32(os, m_base_position);
+	writeV3F32(os, getBasePosition());
 	writeV3F32(os, m_rotation);
 	writeU16(os, getHP());
 
@@ -195,7 +194,7 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 		// Sequence of damage points, starting 0.1 above feet and progressing
 		// upwards in 1 node intervals, stopping below top damage point.
 		for (float dam_height = 0.1f; dam_height < dam_top; dam_height++) {
-			v3s16 p = floatToInt(m_base_position +
+			v3s16 p = floatToInt(getBasePosition() +
 				v3f(0.0f, dam_height * BS, 0.0f), BS);
 			MapNode n = m_env->getMap().getNode(p);
 			const ContentFeatures &c = m_env->getGameDef()->ndef()->get(n);
@@ -207,7 +206,7 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 		}
 
 		// Top damage point
-		v3s16 ptop = floatToInt(m_base_position +
+		v3s16 ptop = floatToInt(getBasePosition() +
 			v3f(0.0f, dam_top * BS, 0.0f), BS);
 		MapNode ntop = m_env->getMap().getNode(ptop);
 		const ContentFeatures &c = m_env->getGameDef()->ndef()->get(ntop);
@@ -285,7 +284,7 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 		if (isAttached())
 			pos = m_last_good_position;
 		else
-			pos = m_base_position;
+			pos = getBasePosition();
 
 		std::string str = generateUpdatePositionCommand(
 			pos,
@@ -344,7 +343,7 @@ std::string PlayerSAO::generateUpdatePhysicsOverrideCommand() const
 
 void PlayerSAO::setBasePosition(v3f position)
 {
-	if (m_player && position != m_base_position)
+	if (m_player && position != getBasePosition())
 		m_player->setDirty(true);
 
 	// This needs to be ran for attachments too
@@ -629,7 +628,7 @@ bool PlayerSAO::checkMovementCheat()
 	if (m_is_singleplayer ||
 			isAttached() ||
 			g_settings->getBool("disable_anticheat")) {
-		m_last_good_position = m_base_position;
+		m_last_good_position = getBasePosition();
 		return false;
 	}
 
@@ -694,7 +693,7 @@ bool PlayerSAO::checkMovementCheat()
 	if (player_max_jump < 0.0001f)
 		player_max_jump = 0.0001f;
 
-	v3f diff = (m_base_position - m_last_good_position);
+	v3f diff = (getBasePosition() - m_last_good_position);
 	float d_vert = diff.Y;
 	diff.Y = 0;
 	float d_horiz = diff.getLength();
@@ -710,7 +709,7 @@ bool PlayerSAO::checkMovementCheat()
 	}
 
 	if (m_move_pool.grab(required_time)) {
-		m_last_good_position = m_base_position;
+		m_last_good_position = getBasePosition();
 	} else {
 		const float LAG_POOL_MIN = 5.0;
 		float lag_pool_max = m_env->getMaxLagEstimate() * 2.0;
@@ -732,8 +731,8 @@ bool PlayerSAO::getCollisionBox(aabb3f *toset) const
 	toset->MinEdge = m_prop.collisionbox.MinEdge * BS;
 	toset->MaxEdge = m_prop.collisionbox.MaxEdge * BS;
 
-	toset->MinEdge += m_base_position;
-	toset->MaxEdge += m_base_position;
+	toset->MinEdge += getBasePosition();
+	toset->MaxEdge += getBasePosition();
 	return true;
 }
 
diff --git a/src/server/player_sao.h b/src/server/player_sao.h
index b26304589..8a11ab934 100644
--- a/src/server/player_sao.h
+++ b/src/server/player_sao.h
@@ -182,7 +182,7 @@ class PlayerSAO : public UnitSAO
 
 	void finalize(RemotePlayer *player, const std::set<std::string> &privs);
 
-	v3f getEyePosition() const { return m_base_position + getEyeOffset(); }
+	v3f getEyePosition() const { return getBasePosition() + getEyeOffset(); }
 	v3f getEyeOffset() const;
 	float getZoomFOV() const;
 
diff --git a/src/server/serveractiveobject.cpp b/src/server/serveractiveobject.cpp
index fb09464cf..c881047a8 100644
--- a/src/server/serveractiveobject.cpp
+++ b/src/server/serveractiveobject.cpp
@@ -31,6 +31,12 @@ ServerActiveObject::ServerActiveObject(ServerEnvironment *env, v3f pos):
 {
 }
 
+void ServerActiveObject::setBasePosition(v3f pos) {
+	m_base_position = pos;
+	if (m_env) // HACK this doesn't feel right; *when* is m_env null?
+		ServerEnvironment_updatePos(m_env, pos, getId());
+}
+
 float ServerActiveObject::getMinimumSavedMovement()
 {
 	return 2.0*BS;
diff --git a/src/server/serveractiveobject.h b/src/server/serveractiveobject.h
index 2d09e34c1..a37cad9be 100644
--- a/src/server/serveractiveobject.h
+++ b/src/server/serveractiveobject.h
@@ -44,6 +44,7 @@ Some planning
 */
 
 class ServerEnvironment;
+void ServerEnvironment_updatePos(ServerEnvironment *senv, const v3f &pos, u16 id);
 struct ItemStack;
 struct ToolCapabilities;
 struct ObjectProperties;
@@ -77,7 +78,7 @@ class ServerActiveObject : public ActiveObject
 		Some simple getters/setters
 	*/
 	v3f getBasePosition() const { return m_base_position; }
-	void setBasePosition(v3f pos){ m_base_position = pos; }
+	void setBasePosition(v3f pos);
 	ServerEnvironment* getEnv(){ return m_env; }
 
 	/*
@@ -244,7 +245,6 @@ class ServerActiveObject : public ActiveObject
 	virtual void onDetach(int parent_id) {}
 
 	ServerEnvironment *m_env;
-	v3f m_base_position;
 	std::unordered_set<u32> m_attached_particle_spawners;
 
 	/*
@@ -272,4 +272,6 @@ class ServerActiveObject : public ActiveObject
 		Queue of messages to be sent to the client
 	*/
 	std::queue<ActiveObjectMessage> m_messages_out;
+private:
+	v3f m_base_position; // setBasePosition updates index and MUST be called
 };
diff --git a/src/serverenvironment.cpp b/src/serverenvironment.cpp
index 87bb39d4c..39e7aecc2 100644
--- a/src/serverenvironment.cpp
+++ b/src/serverenvironment.cpp
@@ -2528,3 +2528,8 @@ bool ServerEnvironment::migrateAuthDatabase(
 	}
 	return true;
 }
+
+// HACK
+void ServerEnvironment_updatePos(ServerEnvironment *senv, const v3f &pos, u16 id) {
+	senv->updatePos(pos, id);
+}
\ No newline at end of file
diff --git a/src/serverenvironment.h b/src/serverenvironment.h
index d5d45d0f4..71e5daa34 100644
--- a/src/serverenvironment.h
+++ b/src/serverenvironment.h
@@ -334,6 +334,10 @@ class ServerEnvironment final : public Environment
 	// Find the daylight value at pos with a Depth First Search
 	u8 findSunlight(v3s16 pos) const;
 
+	void updatePos(const v3f &pos, u16 id) {
+		return m_ao_manager.updatePos(pos, id);
+	}
+
 	// Find all active objects inside a radius around a point
 	void getObjectsInsideRadius(std::vector<ServerActiveObject *> &objects, const v3f &pos, float radius,
 			std::function<bool(ServerActiveObject *obj)> include_obj_cb)
@@ -513,3 +517,6 @@ class ServerEnvironment final : public Environment
 	std::unique_ptr<ServerActiveObject> createSAO(ActiveObjectType type, v3f pos,
 			const std::string &data);
 };
+
+// HACK
+void ServerEnvironment_updatePos(ServerEnvironment *senv, const v3f &pos, u16 id);
\ No newline at end of file