diff --git a/.clang-tidy b/.clang-tidy
index 4d5dbae..eace73e 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -57,6 +57,7 @@ misc-*,
 readability-duplicate-include,
 -misc-non-private-member-variables-in-classes,
 -misc-no-recursion,
+-misc-include-cleaner,
 bugprone-*,
 clang-analyzer-*,
 modernize-*,
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7a155a2..7c564a0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,6 +11,10 @@ endif()
 
 include(deps/nostalgia/deps/buildcore/base.cmake)
 
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
 if(BUILDCORE_TARGET STREQUAL "gba")
 	include(deps/nostalgia/deps/gbabuildcore/base.cmake)
 else()
diff --git a/src/jasper/modules/core/include/jasper/core/animpage.hpp b/src/jasper/modules/core/include/jasper/core/animpage.hpp
index 8384528..520ff26 100644
--- a/src/jasper/modules/core/include/jasper/core/animpage.hpp
+++ b/src/jasper/modules/core/include/jasper/core/animpage.hpp
@@ -19,8 +19,8 @@ struct AnimPage {
 };
 
 oxModelBegin(AnimPage)
-	oxModelFieldRename(tilesheet_path, tilesheetPath)
-	oxModelFieldRename(subsheet_path, subsheetPath)
+	oxModelFieldRename(tilesheetPath, tilesheet_path)
+	oxModelFieldRename(subsheetPath, subsheet_path)
 oxModelEnd()
 
 
diff --git a/src/jasper/modules/world/include/jasper/world/prefab.hpp b/src/jasper/modules/world/include/jasper/world/prefab.hpp
deleted file mode 100644
index 25d5198..0000000
--- a/src/jasper/modules/world/include/jasper/world/prefab.hpp
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
- */
-
-#pragma once
-
-#include <ox/std/size.hpp>
-#include <ox/std/string.hpp>
-#include <ox/model/def.hpp>
-
-#include <nostalgia/core/core.hpp>
-
-#include <jasper/core/animpage.hpp>
-
-namespace jasper::world {
-
-struct PrefabDoc {
-	constexpr static auto TypeName = "net.drinkingtea.jasper.world.PrefabDoc";
-	constexpr static auto TypeVersion = 1;
-	constexpr static auto Preloadable = true;
-
-	ox::Size footprint;
-	ox::Size visibleSz;
-	ox::String tilesheetPath;
-	ox::String subsheetPath;
-};
-
-oxModelBegin(PrefabDoc)
-	oxModelField(footprint)
-	oxModelFieldRename(visible_size, visibleSz)
-	oxModelFieldRename(tilesheet_path, tilesheetPath)
-	oxModelFieldRename(subsheet_path, subsheetPath)
-oxModelEnd()
-
-}
diff --git a/src/jasper/modules/world/include/jasper/world/world.hpp b/src/jasper/modules/world/include/jasper/world/world.hpp
index 8b06c64..3b745c3 100644
--- a/src/jasper/modules/world/include/jasper/world/world.hpp
+++ b/src/jasper/modules/world/include/jasper/world/world.hpp
@@ -7,7 +7,6 @@
 #include <nostalgia/core/context.hpp>
 
 #include "consts.hpp"
-#include "prefab.hpp"
 #include "worldobject.hpp"
 #include "worldstatic.hpp"
 
@@ -25,7 +24,7 @@ class World {
 		ox::Error setupDisplay(ncore::Context &ctx) const noexcept;
 
 	private:
-		void setupLayer(ncore::Context&, ox::Vector<uint16_t> const&layer, unsigned layerNo) const noexcept;
+		void setupLayer(ncore::Context&, uint_t lyr, uint_t cbb) const noexcept;
 
 };
 
diff --git a/src/jasper/modules/world/include/jasper/world/worldobject.hpp b/src/jasper/modules/world/include/jasper/world/worldobject.hpp
index 38abdc6..b4c2211 100644
--- a/src/jasper/modules/world/include/jasper/world/worldobject.hpp
+++ b/src/jasper/modules/world/include/jasper/world/worldobject.hpp
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <ox/std/array.hpp>
+
 #include <nostalgia/core/context.hpp>
 #include <nostalgia/core/tilesheet.hpp>
 
@@ -14,7 +16,6 @@ namespace ncore = nostalgia::core;
 struct PaletteCycle {
 	static constexpr auto TypeName = "net.drinkingtea.jasper.world.PaletteCycle";
 	static constexpr auto TypeVersion = 1;
-	static constexpr auto Preloadable = true;
 	ox::FileAddress palette;
 	uint16_t intervalMs = 1000;
 };
@@ -27,44 +28,68 @@ oxModelEnd()
 
 using CollisionMap = uint32_t;
 
+enum class ObjectType: uint8_t {
+	None         = 0,
+	NormalBgTile = 1,
+	NormalSprite = 2,
+	Person       = 3,
+};
+
+using ObjectId = uint32_t;
+
 struct WorldObject {
 	static constexpr auto TypeName = "net.drinkingtea.jasper.world.WorldObject";
 	static constexpr auto TypeVersion = 1;
-	static constexpr auto Preloadable = true;
-	int id{};
+	ObjectId id{};
 	ox::String name;
 	uint16_t palBank{};
 	ncore::SubSheetId subsheetId{};
 	CollisionMap collisionMap{};
+	uint8_t objectType{};
+	uint8_t ext1{};
+	uint8_t ext2{};
+	uint8_t ext3{};
 };
 
 oxModelBegin(WorldObject)
 	oxModelField(id)
 	oxModelField(name)
 	oxModelField(palBank)
-	oxModelField(subsheetId)
-	oxModelField(collisionMap)
+	oxModelFieldRename(subsheetId, subsheet_id)
+	oxModelFieldRename(collisionMap, collision_map)
+	oxModelFieldRename(objectType, object_type)
+	oxModelField(ext1)
+	oxModelField(ext2)
+	oxModelField(ext3)
 oxModelEnd()
 
+enum class TerrainType: uint8_t {
+	NormalLand,
+	NormalWater,
+};
+
+void bgObjSetTerrainType(WorldObject &obj, TerrainType t) noexcept;
+
+[[nodiscard]]
+TerrainType bgObjGetTerrainType(WorldObject &obj) noexcept;
 
 struct WorldObjectSet {
 	static constexpr auto TypeName = "net.drinkingtea.jasper.world.WorldObjectSet";
 	static constexpr auto TypeVersion = 1;
 	static constexpr auto Preloadable = true;
-	int objIdIdx = 0;
+	ObjectId objIdIdx = 0;
 	ox::FileAddress tilesheet;
 	ox::Vector<PaletteCycle> palettes;
 	ox::Vector<WorldObject> objects;
 };
 
 oxModelBegin(WorldObjectSet)
-	oxModelField(objIdIdx)
+	oxModelFieldRename(objIdIdx, obj_id_idx)
 	oxModelField(tilesheet)
 	oxModelField(palettes)
 	oxModelField(objects)
 oxModelEnd()
 
-
 ox::Error loadObjectSet(WorldObjectSet const&os) noexcept;
 
 }
diff --git a/src/jasper/modules/world/include/jasper/world/worldstatic.hpp b/src/jasper/modules/world/include/jasper/world/worldstatic.hpp
index f73c86a..9799b01 100644
--- a/src/jasper/modules/world/include/jasper/world/worldstatic.hpp
+++ b/src/jasper/modules/world/include/jasper/world/worldstatic.hpp
@@ -12,98 +12,15 @@
 
 #include <nostalgia/core/tilesheet.hpp>
 
+#include <jasper/world/objectcache.hpp>
+
+#include "worlddoc.hpp"
+#include "worldobject.hpp"
+
 namespace jasper::world {
 
 namespace ncore = nostalgia::core;
 
-struct SpriteDoc {
-
-	constexpr static auto TypeName = "net.drinkingtea.jasper.world.SpriteDoc";
-	constexpr static auto TypeVersion = 1;
-	constexpr static auto Preloadable = true;
-
-	ox::String tilesheetPath;
-	ox::Vector<ncore::SubSheetId> subsheetId;
-
-};
-
-struct TileDoc {
-
-	constexpr static auto TypeName = "net.drinkingtea.jasper.world.TileDoc";
-	constexpr static auto TypeVersion = 1;
-	constexpr static auto Preloadable = true;
-
-	ncore::SubSheetId subsheetId = -1;
-	ox::String subsheetPath;
-	uint8_t type = 0;
-	ox::Array<uint8_t, 4> layerAttachments;
-
-	[[nodiscard]]
-	constexpr ox::Result<ncore::SubSheetId> getSubsheetId(ncore::TileSheet const&ts) const noexcept {
-		// prefer the already present ID
-		if (subsheetId > -1) {
-			return subsheetId;
-		}
-		return getIdFor(ts, subsheetPath);
-	}
-
-	[[nodiscard]]
-	constexpr ox::Result<ox::StringView> getSubsheetPath(
-			ncore::TileSheet const&ts) const noexcept {
-		// prefer the already present path
-		if (!subsheetPath.len()) {
-			return getNameFor(ts, subsheetId);
-		}
-		return ox::StringView(subsheetPath);
-	}
-
-};
-
-oxModelBegin(TileDoc)
-	oxModelFieldRename(subsheetId, subsheet_id)
-	oxModelFieldRename(subsheetPath, subsheet_path)
-	oxModelField(type)
-	oxModelFieldRename(layerAttachments, layer_attachments)
-oxModelEnd()
-
-struct WorldDoc {
-
-	using TileMapRow = ox::Vector<TileDoc>;
-	using TileMapLayer = ox::Vector<TileMapRow>;
-	using TileMap = ox::Vector<TileMapLayer>;
-
-	constexpr static auto TypeName = "net.drinkingtea.jasper.world.WorldDoc";
-	constexpr static auto TypeVersion = 1;
-	constexpr static auto Preloadable = true;
-
-	ox::String tilesheet; // path
-	ox::Vector<ox::String> palettes; // paths
-	TileMap tiles;
-
-	[[nodiscard]]
-	constexpr ox::Size size(std::size_t layerIdx) const noexcept {
-		const auto &layer = this->tiles[layerIdx];
-		const auto rowCnt = static_cast<int>(layer.size());
-		if (!rowCnt) {
-			return {};
-		}
-		auto colCnt = layer[0].size();
-		// find shortest row (they should all be the same, but you know this data
-		// could come from a file)
-		for (auto const&row : layer) {
-			colCnt = ox::min(colCnt, row.size());
-		}
-		return {static_cast<int>(colCnt), rowCnt};
-	}
-};
-
-oxModelBegin(WorldDoc)
-	oxModelField(tilesheet)
-	oxModelField(palettes)
-	oxModelField(tiles)
-oxModelEnd()
-
-
 constexpr void setTopEdge(uint8_t &layerAttachments, unsigned val) noexcept {
 	const auto val8 = static_cast<uint8_t>(val);
 	layerAttachments = (layerAttachments & 0b11111100) | val8;
@@ -139,92 +56,69 @@ constexpr unsigned rightEdge(uint8_t layerAttachments) noexcept {
 }
 
 
-struct WorldStatic {
-
-	constexpr static auto TypeName = "net.drinkingtea.jasper.world.WorldStatic";
+struct TileStatic {
+	constexpr static auto TypeName = "net.drinkingtea.jasper.world.TileStatic";
 	constexpr static auto TypeVersion = 1;
-	constexpr static auto Preloadable = true;
-
-	struct Tile {
-		uint16_t &tileMapIdx;
-		uint8_t &tileType;
-		uint8_t &layerAttachments;
-		constexpr Tile(uint16_t &pTileMapIdx, uint8_t &pTileType, uint8_t &pLayerAttachments) noexcept:
-			tileMapIdx(pTileMapIdx),
-			tileType(pTileType),
-			layerAttachments(pLayerAttachments) {
-		}
-	};
-	struct Layer {
-		uint16_t &columns;
-		uint16_t &rows;
-		ox::Vector<uint16_t> &tileMapIdx;
-		ox::Vector<uint8_t> &tileType;
-		ox::Vector<uint8_t> &layerAttachments;
-		constexpr Layer(
-				uint16_t &pColumns,
-				uint16_t &pRows,
-				ox::Vector<uint16_t> &pTileMapIdx,
-				ox::Vector<uint8_t> &pTileType,
-				ox::Vector<uint8_t> &pLayerAttachments) noexcept:
-			columns(pColumns),
-			rows(pRows),
-			tileMapIdx(pTileMapIdx),
-			tileType(pTileType),
-			layerAttachments(pLayerAttachments) {
-		}
-		[[nodiscard]]
-		constexpr Tile tile(std::size_t i) noexcept {
-			return {tileMapIdx[i], tileType[i], layerAttachments[i]};
-		}
-		constexpr auto setDimensions(ox::Size dim) noexcept {
-			columns = static_cast<uint16_t>(dim.width);
-			rows = static_cast<uint16_t>(dim.height);
-			const auto tileCnt = static_cast<unsigned>(columns * rows);
-			tileMapIdx.resize(tileCnt);
-			tileType.resize(tileCnt);
-			layerAttachments.resize(tileCnt);
-		}
-	};
-
-	ox::FileAddress tilesheet;
-	ox::Vector<ox::FileAddress> palettes;
-	// tile layer data
-	ox::Vector<uint16_t> columns;
-	ox::Vector<uint16_t> rows;
-	ox::Vector<ox::Vector<uint16_t>> tileMapIdx;
-	ox::Vector<ox::Vector<uint8_t>>  tileType;
-	ox::Vector<ox::Vector<uint8_t>>  layerAttachments;
-
-	[[nodiscard]]
-	constexpr Layer layer(std::size_t i) noexcept {
-		return {
-			columns[i],
-			rows[i],
-			tileMapIdx[i],
-			tileType[i],
-			layerAttachments[i],
-		};
-	}
-
-	constexpr auto setLayerCnt(std::size_t layerCnt) noexcept {
-		this->layerAttachments.resize(layerCnt);
-		this->columns.resize(layerCnt);
-		this->rows.resize(layerCnt);
-		this->tileMapIdx.resize(layerCnt);
-		this->tileType.resize(layerCnt);
-	}
-
+	uint16_t tileIdx{};
+	uint8_t palBank{};
+	uint8_t tileType{};
+	uint8_t layerAttachments{};
 };
 
-oxModelBegin(WorldStatic)
-	oxModelField(tilesheet)
-	oxModelField(palettes)
-	oxModelField(columns)
-	oxModelField(rows)
-	oxModelField(tileMapIdx)
+oxModelBegin(TileStatic)
+	oxModelField(tileIdx)
+	oxModelField(palBank)
 	oxModelField(tileType)
 	oxModelField(layerAttachments)
 oxModelEnd()
 
+
+struct BgLayer {
+	constexpr static auto TypeName = "net.drinkingtea.jasper.world.BgLayer";
+	constexpr static auto TypeVersion = 1;
+	uint8_t cbb{};
+	ox::Vector<TileStatic> tiles;
+};
+
+oxModelBegin(BgLayer)
+	oxModelField(cbb)
+	oxModelField(tiles)
+oxModelEnd()
+
+
+struct WorldStatic {
+	constexpr static auto TypeName = "net.drinkingtea.jasper.world.WorldStatic";
+	constexpr static auto TypeVersion = 1;
+	constexpr static auto Preloadable = true;
+	ncore::TileSheetSet tilesheets;
+	ox::Vector<PaletteCycle> palettes;
+	int16_t columns{};
+	int16_t rows{};
+	ox::Array<BgLayer, 3> map;
+};
+
+oxModelBegin(WorldStatic)
+	oxModelField(tilesheets)
+	oxModelField(palettes)
+	oxModelField(columns)
+	oxModelField(rows)
+	oxModelField(map)
+oxModelEnd()
+
+ox::Result<WorldStatic> loadWorldStatic(ObjectCache const&objCache, WorldDoc const&doc) noexcept;
+
+[[nodiscard]]
+auto &tile(ox::CommonRefWith<WorldStatic> auto &ws, size_t lyr, size_t col, size_t row) noexcept {
+	auto const idx = row * static_cast<size_t>(ws.columns) + col;
+	return ws.map[lyr].tiles[idx];
+}
+
+[[nodiscard]]
+auto &cbb(ox::CommonRefWith<WorldStatic> auto &ws, size_t lyr) noexcept {
+	return ws.map[lyr].cbb;
+}
+
+[[nodiscard]]
+bool isValid(WorldStatic const&ws) noexcept;
+
 }
diff --git a/src/jasper/modules/world/src/CMakeLists.txt b/src/jasper/modules/world/src/CMakeLists.txt
index b1ce3f1..73bdbe1 100644
--- a/src/jasper/modules/world/src/CMakeLists.txt
+++ b/src/jasper/modules/world/src/CMakeLists.txt
@@ -1,7 +1,10 @@
 
 add_library(
 	JasperWorld
+		objectcache.cpp
         world.cpp
+		worlddoc.cpp
+		worldobject.cpp
 		worldstatic.cpp
 )
 
diff --git a/src/jasper/modules/world/src/keel/typeconv.cpp b/src/jasper/modules/world/src/keel/typeconv.cpp
index 69a63db..09f28ec 100644
--- a/src/jasper/modules/world/src/keel/typeconv.cpp
+++ b/src/jasper/modules/world/src/keel/typeconv.cpp
@@ -5,66 +5,18 @@
 #include <nostalgia/core/gfx.hpp>
 #include <keel/media.hpp>
 
+#include <jasper/world/objectcache.hpp>
+
 #include "typeconv.hpp"
 
 namespace jasper::world {
 
-namespace ncore = nostalgia::core;
-
-[[nodiscard]]
-constexpr unsigned adjustLayerAttachment(unsigned layer, unsigned attachment) noexcept {
-	if (attachment == 0) {
-		return layer;
-	} else {
-		return attachment - 1;
-	}
-}
-
-constexpr void setLayerAttachments(unsigned layer, TileDoc const&srcTile, WorldStatic::Tile &dstTile) noexcept {
-	setTopEdge(
-			dstTile.layerAttachments,
-			adjustLayerAttachment(layer, srcTile.layerAttachments[0]));
-	setBottomEdge(
-			dstTile.layerAttachments,
-			adjustLayerAttachment(layer, srcTile.layerAttachments[1]));
-	setLeftEdge(
-			dstTile.layerAttachments,
-			adjustLayerAttachment(layer, srcTile.layerAttachments[2]));
-	setRightEdge(
-			dstTile.layerAttachments,
-			adjustLayerAttachment(layer, srcTile.layerAttachments[3]));
-}
-
 ox::Error WorldDocToWorldStaticConverter::convert(
-		keel::Context &ctx,
+		keel::Context &kctx,
 		WorldDoc &src,
 		WorldStatic &dst) const noexcept {
-	oxRequire(ts, keel::readObj<ncore::TileSheet>(ctx, src.tilesheet));
-	const auto layerCnt = src.tiles.size();
-	dst.setLayerCnt(layerCnt);
-	dst.tilesheet = ox::FileAddress(src.tilesheet);
-	dst.palettes.reserve(src.palettes.size());
-	for (const auto &pal : src.palettes) {
-		dst.palettes.emplace_back(pal);
-	}
-	for (auto layerIdx = 0u; const auto &layer : src.tiles) {
-		const auto layerDim = src.size(layerIdx);
-		auto dstLayer = dst.layer(layerIdx);
-		dstLayer.setDimensions(layerDim);
-		for (auto tileIdx = 0u; const auto &row : layer) {
-			for (const auto &srcTile : row) {
-				auto dstTile = dstLayer.tile(tileIdx);
-				dstTile.tileType = srcTile.type;
-				oxRequire(path, srcTile.getSubsheetPath(*ts));
-				oxRequire(mapIdx, getTileOffset(*ts, path));
-				dstTile.tileMapIdx = static_cast<uint16_t>(mapIdx);
-				setLayerAttachments(layerIdx, srcTile, dstTile);
-				++tileIdx;
-			}
-		}
-		++layerIdx;
-	}
-	return {};
+	oxRequire(oc, buildObjCache(kctx, src));
+	return loadWorldStatic(oc, src).moveTo(dst);
 }
 
 }
diff --git a/src/jasper/modules/world/src/objectcache.cpp b/src/jasper/modules/world/src/objectcache.cpp
new file mode 100644
index 0000000..01ec54a
--- /dev/null
+++ b/src/jasper/modules/world/src/objectcache.cpp
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <keel/media.hpp>
+
+#include <nostalgia/core/gfx.hpp>
+
+#include <jasper/world/objectcache.hpp>
+
+namespace jasper::world {
+
+void ObjectCache::clear() noexcept {
+	m_tileIdx = 0;
+	m_palBank = 0;
+	m_tilesheets.clear();
+	m_palettes.clear();
+	m_objSets.clear();
+}
+
+ox::Error ObjectCache::indexSet(
+		keel::Context &kctx,
+		uint64_t setId,
+		WorldObjectSet const&objSet) noexcept {
+	auto &set = m_objSets.emplace_back(ObjSet{
+		.setId = setId,
+		.objects = {},
+	});
+	oxRequire(ts, readObj<ncore::TileSheet>(kctx, objSet.tilesheet));
+	for (auto const&obj : objSet.objects) {
+		set.objects.emplace_back(Obj{
+			.id = obj.id,
+			.palBank = static_cast<uint16_t>(obj.palBank + m_palBank),
+			.tileIdx = getTileIdx(*ts, obj.subsheetId) + m_tileIdx,
+		});
+	}
+	auto const tileCnt = getTileCnt(*ts);
+	m_tileIdx += tileCnt;
+	m_tilesheets.emplace_back(objSet.tilesheet);
+	m_tilesheetSet.bpp = 4;
+	addTileSheet(objSet.tilesheet, static_cast<int32_t>(tileCnt));
+	for (auto const&pal : objSet.palettes) {
+		m_palettes.emplace_back(pal);
+		oxRequire(p, readObj<ncore::Palette>(kctx, pal.palette));
+		m_palBank += largestPage(*p);
+	}
+	return {};
+}
+
+ox::Optional<ObjectCache::Obj> ObjectCache::obj(uint64_t setId, ObjectId objId) const noexcept {
+	for (auto &set : m_objSets) {
+		if (set.setId == setId) {
+			for (auto &obj : set.objects) {
+				if (obj.id == objId) {
+					return ox::Optional<ObjectCache::Obj>{ox::in_place, obj};
+				}
+			}
+			break;
+		}
+	}
+	return {};
+}
+
+ncore::TileSheetSet const&ObjectCache::tilesheets() const noexcept {
+	return m_tilesheetSet;
+}
+
+ox::Vector<PaletteCycle> const&ObjectCache::palettes() const noexcept {
+	return m_palettes;
+}
+
+void ObjectCache::addTileSheet(ox::FileAddress path, int32_t tiles) noexcept {
+	ncore::TileSheetSetEntry entry;
+	entry.tilesheet = std::move(path);
+	entry.sections.push_back({
+		.begin = 0,
+		.tiles = tiles,
+	});
+	m_tilesheetSet.entries.emplace_back(std::move(entry));
+}
+
+ox::Result<ObjectCache> buildObjCache(keel::Context &kctx, WorldDoc const&doc) noexcept {
+	ObjectCache cache;
+	for (auto &set : doc.objSets) {
+		oxRequire(s, readObj<WorldObjectSet>(kctx, set.path));
+		oxReturnError(cache.indexSet(kctx, set.id, *s));
+	}
+	return cache;
+}
+
+}
diff --git a/src/jasper/modules/world/src/studio/CMakeLists.txt b/src/jasper/modules/world/src/studio/CMakeLists.txt
index 23aa93c..d41b7f7 100644
--- a/src/jasper/modules/world/src/studio/CMakeLists.txt
+++ b/src/jasper/modules/world/src/studio/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_library(
 	JasperWorld-Studio
 		studiomodule.cpp
+		worldeditor/commands/commands.hpp
 )
 
 target_link_libraries(
diff --git a/src/jasper/modules/world/src/studio/worldeditor/CMakeLists.txt b/src/jasper/modules/world/src/studio/worldeditor/CMakeLists.txt
index c9e714c..2d54841 100644
--- a/src/jasper/modules/world/src/studio/worldeditor/CMakeLists.txt
+++ b/src/jasper/modules/world/src/studio/worldeditor/CMakeLists.txt
@@ -1,6 +1,8 @@
 target_sources(
 	JasperWorld-Studio PRIVATE
+		commands/addrmobjectset.cpp
+		commands/editsize.cpp
+		objectexplorer.cpp
 		worldeditor-imgui.cpp
-        worldeditor.cpp
 		worldeditorview.cpp
-)
\ No newline at end of file
+)
diff --git a/src/jasper/modules/world/src/studio/worldeditor/commands/addrmobjectset.cpp b/src/jasper/modules/world/src/studio/worldeditor/commands/addrmobjectset.cpp
new file mode 100644
index 0000000..631b9e1
--- /dev/null
+++ b/src/jasper/modules/world/src/studio/worldeditor/commands/addrmobjectset.cpp
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include "commands.hpp"
+#include "addrmobjectset.hpp"
+
+namespace jasper::world {
+
+AddObjectSet::AddObjectSet(WorldDoc &doc, ox::StringView objSetPath):
+		m_doc(doc),
+		m_path(ox::String(objSetPath)) {
+	for (auto const&o : m_doc.objSets) {
+		if (o.path > objSetPath) {
+			break;
+		} else if (o.path == objSetPath) {
+			throw ox::Exception(OxError(1, "Path already exists in doc"));
+		}
+		++m_insertIdx;
+	}
+}
+
+void AddObjectSet::redo() noexcept {
+	m_doc.objSets.insert(m_insertIdx, {
+		.path = std::move(m_path),
+		.id = ++m_doc.objSetIdIdx,
+	});
+}
+
+void AddObjectSet::undo() noexcept {
+	m_path = std::move(m_doc.objSets[m_insertIdx].path);
+	--m_doc.objSetIdIdx;
+	oxIgnoreError(m_doc.objSets.erase(m_insertIdx));
+}
+
+int AddObjectSet::commandId() const noexcept {
+	return static_cast<int>(WorldEditorCommand::AddObjectSet);
+}
+
+
+RmObjectSet::RmObjectSet(WorldDoc &doc, size_t idx):
+		m_doc(doc),
+		m_idx(idx) {
+}
+
+void RmObjectSet::redo() noexcept {
+	m_entry = std::move(m_doc.objSets[m_idx]);
+	oxIgnoreError(m_doc.objSets.erase(m_idx));
+}
+
+void RmObjectSet::undo() noexcept {
+	m_doc.objSets.emplace(m_idx, std::move(m_entry));
+}
+
+int RmObjectSet::commandId() const noexcept {
+	return static_cast<int>(WorldEditorCommand::RmObjectSet);
+}
+
+}
diff --git a/src/jasper/modules/world/src/studio/worldeditor/commands/addrmobjectset.hpp b/src/jasper/modules/world/src/studio/worldeditor/commands/addrmobjectset.hpp
new file mode 100644
index 0000000..d9846cd
--- /dev/null
+++ b/src/jasper/modules/world/src/studio/worldeditor/commands/addrmobjectset.hpp
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#include <ox/fs/fs.hpp>
+
+#include <studio/undostack.hpp>
+
+#include <jasper/world/world.hpp>
+
+namespace jasper::world {
+
+class AddObjectSet: public studio::UndoCommand {
+	private:
+		WorldDoc &m_doc;
+		size_t m_insertIdx{};
+		ox::String m_path;
+	public:
+		AddObjectSet(WorldDoc &doc, ox::StringView objSetPath);
+		void redo() noexcept override;
+		void undo() noexcept override;
+		[[nodiscard]]
+		int commandId() const noexcept override;
+		[[nodiscard]]
+		inline size_t insertIdx() const noexcept {
+			return m_insertIdx;
+		}
+};
+
+class RmObjectSet: public studio::UndoCommand {
+	private:
+		WorldDoc &m_doc;
+		size_t m_idx{};
+		ObjectSetEntry m_entry;
+	public:
+		RmObjectSet(WorldDoc &doc, size_t idx);
+		void redo() noexcept override;
+		void undo() noexcept override;
+		[[nodiscard]]
+		int commandId() const noexcept override;
+};
+
+}
diff --git a/src/jasper/modules/world/src/studio/worldeditor/commands/commands.hpp b/src/jasper/modules/world/src/studio/worldeditor/commands/commands.hpp
new file mode 100644
index 0000000..96acb75
--- /dev/null
+++ b/src/jasper/modules/world/src/studio/worldeditor/commands/commands.hpp
@@ -0,0 +1,16 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+namespace jasper::world {
+
+enum class WorldEditorCommand {
+	None,
+	AddObjectSet,
+	RmObjectSet,
+	EditWorldSize,
+};
+
+}
diff --git a/src/jasper/modules/world/src/studio/worldeditor/commands/editsize.cpp b/src/jasper/modules/world/src/studio/worldeditor/commands/editsize.cpp
new file mode 100644
index 0000000..69fd143
--- /dev/null
+++ b/src/jasper/modules/world/src/studio/worldeditor/commands/editsize.cpp
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include "commands.hpp"
+#include "editsize.hpp"
+
+namespace jasper::world {
+
+EditWorldSize::EditWorldSize(WorldDoc &doc, ox::Size const&size):
+		m_doc(doc),
+		m_oldSize(m_doc.columns, m_doc.rows),
+		m_newVal(size) {
+}
+
+void EditWorldSize::redo() noexcept {
+	m_oldMap = m_doc.tiles;
+	resize(m_doc, m_newVal);
+}
+
+void EditWorldSize::undo() noexcept {
+	resize(m_doc, m_oldSize);
+	m_doc.tiles = std::move(m_oldMap);
+}
+
+int EditWorldSize::commandId() const noexcept {
+	return static_cast<int>(WorldEditorCommand::EditWorldSize);
+}
+
+}
diff --git a/src/jasper/modules/world/src/studio/worldeditor/commands/editsize.hpp b/src/jasper/modules/world/src/studio/worldeditor/commands/editsize.hpp
new file mode 100644
index 0000000..56f473d
--- /dev/null
+++ b/src/jasper/modules/world/src/studio/worldeditor/commands/editsize.hpp
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#include <ox/fs/fs.hpp>
+
+#include <studio/undostack.hpp>
+
+#include <jasper/world/world.hpp>
+
+namespace jasper::world {
+
+class EditWorldSize: public studio::UndoCommand {
+	private:
+		WorldDoc &m_doc;
+		size_t m_insertIdx{};
+		ox::Size const m_oldSize;
+		WorldDoc::TileMap m_oldMap;
+		ox::Size const m_newVal;
+	public:
+		EditWorldSize(WorldDoc &doc, ox::Size const&size);
+		void redo() noexcept override;
+		void undo() noexcept override;
+		[[nodiscard]]
+		int commandId() const noexcept override;
+		[[nodiscard]]
+		inline size_t insertIdx() const noexcept {
+			return m_insertIdx;
+		}
+};
+
+}
diff --git a/src/jasper/modules/world/src/studio/worldeditor/objectexplorer.cpp b/src/jasper/modules/world/src/studio/worldeditor/objectexplorer.cpp
new file mode 100644
index 0000000..dc647f0
--- /dev/null
+++ b/src/jasper/modules/world/src/studio/worldeditor/objectexplorer.cpp
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include "objectexplorer.hpp"
+
+namespace studio {
+
+ObjectExplorerModel::ObjectExplorerModel(ox::StringView name, ObjectExplorerModel *parent) noexcept:
+		m_parent(parent),
+		m_name(name),
+		m_fullPath(m_parent ? (m_parent->m_fullPath + "/" + m_name) : ox::String{}) {
+}
+
+void ObjectExplorerModel::draw(turbine::Context &ctx) const noexcept {
+	constexpr auto dirFlags = ImGuiTreeNodeFlags_OpenOnArrow | ImGuiTreeNodeFlags_OpenOnDoubleClick;
+	if (!m_children.empty()) {
+		if (ImGui::TreeNodeEx(m_name.c_str(), dirFlags)) {
+			for (auto const&child : m_children) {
+				child->draw(ctx);
+			}
+			ImGui::TreePop();
+		}
+	} else {
+		auto const name = ox::sfmt<ox::BasicString<255>>("{}##{}", m_name, m_fullPath);
+		if (ImGui::TreeNodeEx(name.c_str(), ImGuiTreeNodeFlags_Leaf)) {
+			if (ImGui::IsItemHovered() && ImGui::IsMouseDoubleClicked(0)) {
+			}
+			ImGui::TreePop();
+		}
+	}
+}
+
+}
diff --git a/src/jasper/modules/world/src/studio/worldeditor/objectexplorer.hpp b/src/jasper/modules/world/src/studio/worldeditor/objectexplorer.hpp
new file mode 100644
index 0000000..549f73d
--- /dev/null
+++ b/src/jasper/modules/world/src/studio/worldeditor/objectexplorer.hpp
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#include <turbine/turbine.hpp>
+
+namespace studio {
+
+class ObjectExplorerModel {
+	private:
+		ObjectExplorerModel *m_parent{};
+		ox::String m_name;
+		ox::String m_fullPath;
+		ox::Vector<ox::UPtr<ObjectExplorerModel>> m_children;
+	public:
+		explicit ObjectExplorerModel(ox::StringView name, ObjectExplorerModel *parent = {}) noexcept;
+		void draw(turbine::Context &ctx) const noexcept;
+	private:
+};
+
+}
diff --git a/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.cpp b/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.cpp
index 5b39d81..40c37d0 100644
--- a/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.cpp
+++ b/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.cpp
@@ -4,23 +4,151 @@
 
 #include <imgui.h>
 
+#include <ox/std/ignore.hpp>
+
 #include <keel/media.hpp>
 
+#include <studio/imguiutil.hpp>
+
+#include "commands/addrmobjectset.hpp"
+#include "commands/editsize.hpp"
+
 #include "worldeditor-imgui.hpp"
 
 namespace jasper::world {
 
-WorldEditorImGui::WorldEditorImGui(studio::StudioContext &ctx, ox::StringView path):
-	Editor(path),
-	m_ctx(ctx.tctx),
-	m_editor(m_ctx, path),
-	m_view(m_ctx, m_editor.world()) {
+namespace ig = studio::ig;
+
+constexpr auto SqrBtnSize = ImVec2(ig::BtnSz.y, ig::BtnSz.y);
+
+
+struct WorldTileDragDrop {
+	static constexpr auto TypeName = "net.drinkingtea.jasper.world.studio.WorldTileDragDrop";
+	static constexpr auto TypeVersion = 1;
+	ox::String setPath;
+	ox::String objName;
+};
+
+oxModelBegin(WorldTileDragDrop)
+	oxModelField(setPath)
+	oxModelField(objName)
+oxModelEnd()
+
+
+static WorldDoc makeValid(WorldDoc doc) noexcept {
+	for (auto &lyr : doc.tiles) {
+		lyr.resize(static_cast<size_t>(doc.columns));
+		for (auto &row : lyr) {
+			row.resize(static_cast<size_t>(doc.rows));
+		}
+	}
+	return doc;
+}
+
+
+WorldEditorImGui::WorldEditorImGui(studio::StudioContext &sctx, ox::StringView path):
+		Editor(path),
+		m_sctx(sctx),
+		m_doc(makeValid(*readObj<WorldDoc>(keelCtx(m_sctx.tctx), path).unwrapThrow())),
+		m_objCache(buildObjCache(keelCtx(m_sctx.tctx), m_doc).unwrapThrow()),
+		m_worldStatic(loadWorldStatic(m_objCache, m_doc)),
+		m_view(m_sctx.tctx, m_worldStatic) {
+	oxThrowError(loadObjectSets());
 	setRequiresConstantRefresh(false);
+	m_objSetPicker.filePicked.connect(this, &WorldEditorImGui::addObjSet);
+	m_sctx.project->fileUpdated.connect(this, &WorldEditorImGui::handleObjectSetUpdate);
 }
 
 void WorldEditorImGui::draw(turbine::Context&) noexcept {
+	const auto paneSize = ImGui::GetContentRegionAvail();
+	constexpr auto resourcesWidth = 300.f;
+	{
+		ig::ChildStackItem const worldView{"WorldView", ImVec2(paneSize.x - resourcesWidth, 0)};
+		drawWorldView();
+	}
+	ImGui::SameLine();
+	{
+		ig::ChildStackItem const worldView{"RightPane"};
+		drawPropEditor();
+		ImGui::Separator();
+		drawResources();
+	}
+	m_objSetPicker.draw();
+}
+
+void WorldEditorImGui::onActivated() noexcept {
+	oxLogError(m_view.setupWorld());
+}
+
+ox::Error WorldEditorImGui::saveItem() noexcept {
+	return m_sctx.project->writeObj(itemPath(), m_doc, ox::ClawFormat::Organic);
+}
+
+void WorldEditorImGui::drawObjSetSelector() noexcept {
+	ig::IDStackItem const idStackItem("ObjSetSelector");
+	if (ig::PushButton("+", SqrBtnSize)) {
+		m_objSetPicker.show();
+	}
+	ImGui::SameLine();
+	if (ig::PushButton("-", SqrBtnSize)) {
+		rmObjSet();
+	}
+	ig::ListBox("Object Sets", [this](size_t i) -> ox::CStringView {
+		return m_doc.objSets[i].path;
+	}, m_doc.objSets.size(), m_palMgr.selectedIdx);
+}
+
+void WorldEditorImGui::drawObjSelector() noexcept {
+	ig::IDStackItem const idStackItem("ObjSelector");
+	for (auto const&set : m_objSets) {
+		constexpr auto flags = ImGuiTreeNodeFlags_OpenOnArrow | ImGuiTreeNodeFlags_OpenOnDoubleClick;
+		if (ImGui::TreeNodeEx(set.name.c_str(), flags)) {
+			for (auto const&obj : set.set->objects) {
+				if (ImGui::TreeNodeEx(obj.name.c_str(), ImGuiTreeNodeFlags_Leaf)) {
+					ImGui::TreePop();
+				}
+				ig::dragDropSource([set, obj] {
+				std::ignore = ig::setDragDropPayload("WorldTile", WorldTileDragDrop{
+						.setPath = ox::String(set.name),
+						.objName = ox::String(obj.name)});
+					ImGui::Text("%s", obj.name.c_str());
+				});
+			}
+			ImGui::TreePop();
+		}
+	}
+}
+
+void WorldEditorImGui::drawPropEditor() noexcept {
+	ig::IDStackItem const idStackItem("PropEditor");
+	int width{m_doc.columns};
+	int height{m_doc.rows};
+	if (ImGui::InputInt("Map Width", &width, 1)) {
+		pushCommand<EditWorldSize>(m_doc, ox::Size{width, m_doc.rows});
+	}
+	if (ImGui::InputInt("Map Height", &height, 1)) {
+		pushCommand<EditWorldSize>(m_doc, ox::Size{m_doc.columns, height});
+	}
+}
+
+void WorldEditorImGui::drawResources() noexcept {
+	ig::IDStackItem const idStackItem("Resources");
+	drawObjSetSelector();
+	drawObjSelector();
+}
+
+[[nodiscard]]
+static ox::Vec2 dropPos(ox::Vec2 dropPos) noexcept {
+	auto const winPos = ImGui::GetWindowPos();
+	dropPos.x -= winPos.x;
+	dropPos.y -= winPos.y;
+	return dropPos;
+}
+
+void WorldEditorImGui::drawWorldView() noexcept {
+	ig::IDStackItem const idStackItem("WorldView");
 	auto const paneSize = ImGui::GetContentRegionAvail();
-	m_view.draw(ox::Size{static_cast<int>(paneSize.x), static_cast<int>(paneSize.y)});
+	m_view.draw({static_cast<int>(paneSize.x), static_cast<int>(paneSize.y)});
 	auto &fb = m_view.framebuffer();
 	auto const fbWidth = static_cast<float>(fb.width);
 	auto const fbHeight = static_cast<float>(fb.height);
@@ -37,22 +165,46 @@ void WorldEditorImGui::draw(turbine::Context&) noexcept {
 		xScale = 1;
 		yScale = srcW / dstW;
 	}
-	uintptr_t const buffId = fb.color.id;
 	ImGui::Image(
-		std::bit_cast<void*>(buffId),
-		paneSize,
-		ImVec2(0, 1),
-		ImVec2(xScale, 1 - yScale));
+			ig::toImTextureID(fb.color.id),
+			paneSize,
+			ImVec2(0, 1),
+			ImVec2(xScale, 1 - yScale));
+	std::ignore = ig::dragDropTarget([] {
+		oxRequire(obj, ig::getDragDropPayload<WorldTileDragDrop>("WorldTile"));
+		oxDebugf("{}: {}", obj.setPath, obj.objName);
+		auto const&io = ImGui::GetIO();
+		auto const mousePos = ox::Vec2(io.MousePos);
+		auto const dropPos = world::dropPos(mousePos);
+		std::cout << dropPos.x << ", " << dropPos.y << '\n';
+		return ox::Error{};
+	});
 }
 
-void WorldEditorImGui::onActivated() noexcept {
-	oxLogError(m_view.setupWorld());
+ox::Error WorldEditorImGui::addObjSet(ox::StringView path) noexcept {
+	pushCommand<AddObjectSet>(m_doc, path);
+	return {};
 }
 
-ox::Error WorldEditorImGui::saveItem() noexcept {
-	const auto sctx = applicationData<studio::StudioContext>(m_ctx);
-	oxReturnError(sctx->project->writeObj(itemPath(), m_editor.world(), ox::ClawFormat::Organic));
-	oxReturnError(keelCtx(m_ctx).assetManager.setAsset(itemPath(), m_editor.world()));
+void WorldEditorImGui::rmObjSet() noexcept {
+	pushCommand<RmObjectSet>(m_doc, m_palMgr.selectedIdx);
+}
+
+ox::Error WorldEditorImGui::handleObjectSetUpdate(ox::StringView path) noexcept {
+	if (ox::any_of(m_doc.objSets.begin(), m_doc.objSets.end(), [path](ObjectSetEntry const&set) {
+			return set.path == path;
+		})) {
+		oxReturnError(buildObjCache(keelCtx(m_sctx.tctx), m_doc).moveTo(m_objCache));
+	}
+	return loadObjectSets();
+}
+
+ox::Error WorldEditorImGui::loadObjectSets() noexcept {
+	m_objSets.clear();
+	for (auto const&set : m_doc.objSets) {
+		oxRequireM(os, readObj<WorldObjectSet>(keelCtx(m_sctx.tctx), set.path));
+		m_objSets.emplace_back(ObjSetRef{ox::String(set.path), std::move(os)});
+	}
 	return {};
 }
 
diff --git a/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.hpp b/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.hpp
index c7a064c..c0214be 100644
--- a/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.hpp
+++ b/src/jasper/modules/world/src/studio/worldeditor/worldeditor-imgui.hpp
@@ -8,7 +8,8 @@
 
 #include <turbine/context.hpp>
 
-#include "worldeditor.hpp"
+#include <jasper/world/objectcache.hpp>
+
 #include "worldeditorview.hpp"
 
 namespace jasper::world {
@@ -16,9 +17,21 @@ namespace jasper::world {
 class WorldEditorImGui: public studio::Editor {
 
 	private:
-		turbine::Context &m_ctx;
-		WorldEditor m_editor;
+		studio::StudioContext &m_sctx;
+		studio::ig::FilePicker m_objSetPicker{
+			m_sctx, ox::String("Choose Object Set"), ox::String(FileExt_jwob)};
+		WorldDoc m_doc;
+		ObjectCache m_objCache;
+		struct ObjSetRef {
+			ox::String name;
+			keel::AssetRef<WorldObjectSet> set;
+		};
+		ox::Vector<ObjSetRef> m_objSets;
+		WorldStatic m_worldStatic;
 		WorldEditorView m_view;
+		struct {
+			size_t selectedIdx{};
+		} m_palMgr;
 
 	public:
 		WorldEditorImGui(studio::StudioContext &ctx, ox::StringView path);
@@ -30,6 +43,26 @@ class WorldEditorImGui: public studio::Editor {
 	protected:
 		ox::Error saveItem() noexcept final;
 
+	private:
+		void drawObjSetSelector() noexcept;
+
+		void drawObjSelector() noexcept;
+
+		void drawPropEditor() noexcept;
+
+		void drawResources() noexcept;
+
+		void drawWorldView() noexcept;
+
+		ox::Error addObjSet(ox::StringView path) noexcept;
+
+		void rmObjSet() noexcept;
+
+		// handles the updating of an object set in case it is one used by this world
+		ox::Error handleObjectSetUpdate(ox::StringView path) noexcept;
+
+		ox::Error loadObjectSets() noexcept;
+
 };
 
 }
diff --git a/src/jasper/modules/world/src/studio/worldeditor/worldeditor.cpp b/src/jasper/modules/world/src/studio/worldeditor/worldeditor.cpp
index c27f4bb..ea80ffd 100644
--- a/src/jasper/modules/world/src/studio/worldeditor/worldeditor.cpp
+++ b/src/jasper/modules/world/src/studio/worldeditor/worldeditor.cpp
@@ -8,9 +8,9 @@
 
 namespace jasper::world {
 
-WorldEditor::WorldEditor(turbine::Context &ctx, ox::StringView path):
-		m_ctx(*applicationData<studio::StudioContext>(ctx)),
-		m_world(*readObj<WorldStatic>(keelCtx(ctx), path).unwrapThrow()) {
+WorldEditor::WorldEditor(studio::StudioContext &ctx, ox::StringView path):
+		m_ctx(ctx),
+		m_world(*readObj<WorldStatic>(keelCtx(m_ctx.tctx), path).unwrapThrow()) {
 }
 
 ox::Error WorldEditor::saveItem() noexcept {
diff --git a/src/jasper/modules/world/src/studio/worldeditor/worldeditor.hpp b/src/jasper/modules/world/src/studio/worldeditor/worldeditor.hpp
index e5e8554..a5c195b 100644
--- a/src/jasper/modules/world/src/studio/worldeditor/worldeditor.hpp
+++ b/src/jasper/modules/world/src/studio/worldeditor/worldeditor.hpp
@@ -19,7 +19,7 @@ class WorldEditor {
 		WorldStatic m_world;
 
 	public:
-		WorldEditor(turbine::Context &ctx, ox::StringView path);
+		WorldEditor(studio::StudioContext &ctx, ox::StringView path);
 
 		[[nodiscard]]
 		WorldStatic const&world() const noexcept {
diff --git a/src/jasper/modules/world/src/studio/worldobjectseteditor/collisionmapview.hpp b/src/jasper/modules/world/src/studio/worldobjectseteditor/collisionmapview.hpp
index d009dd7..9f7e8a4 100644
--- a/src/jasper/modules/world/src/studio/worldobjectseteditor/collisionmapview.hpp
+++ b/src/jasper/modules/world/src/studio/worldobjectseteditor/collisionmapview.hpp
@@ -18,7 +18,7 @@ namespace ncore = nostalgia::core;
 class CollisionView {
 	private:
 		static const glutils::ProgramSource s_programSrc;
-		static constexpr int s_scale = 10;
+		static constexpr int s_scale = 5;
 		ncore::ContextUPtr m_nctx;
 		glutils::FrameBuffer m_frameBuffer;
 		glutils::GLProgram m_shader;
diff --git a/src/jasper/modules/world/src/studio/worldobjectseteditor/worldobjectseteditor-imgui.cpp b/src/jasper/modules/world/src/studio/worldobjectseteditor/worldobjectseteditor-imgui.cpp
index ae0132c..49b3a3f 100644
--- a/src/jasper/modules/world/src/studio/worldobjectseteditor/worldobjectseteditor-imgui.cpp
+++ b/src/jasper/modules/world/src/studio/worldobjectseteditor/worldobjectseteditor-imgui.cpp
@@ -109,18 +109,10 @@ void WorldObjectSetEditorImGui::drawObjSelector() noexcept {
 	if (ig::PushButton("-", btnSize)) {
 		undoStack()->push(ox::make_unique<RmObject>(m_doc, m_selectedObj));
 	}
-	if (ImGui::BeginListBox("Objects")) {
-		for (auto i = 0u; auto const&obj : m_doc.objects) {
-			ig::IDStackItem const idStackItem2(static_cast<int>(i));
-			if (ImGui::Selectable(obj.name.c_str(), m_selectedObj == i)) {
-				if (i != m_selectedObj) {
-					m_selectedObj = i;
-					loadObj();
-				}
-			}
-			++i;
-		}
-		ImGui::EndListBox();
+	if (ig::ListBox("Objects", [this](size_t i) -> ox::CStringView {
+			return m_doc.objects[i].name;
+		}, m_doc.objects.size(), m_selectedObj)) {
+		loadObj();
 	}
 }
 
diff --git a/src/jasper/modules/world/src/world.cpp b/src/jasper/modules/world/src/world.cpp
index add1011..8500aa5 100644
--- a/src/jasper/modules/world/src/world.cpp
+++ b/src/jasper/modules/world/src/world.cpp
@@ -18,14 +18,14 @@ ox::Error World::setupDisplay(ncore::Context &ctx) const noexcept {
 	if (m_worldStatic.palettes.empty()) {
 		return OxError(1, "World has no palettes");
 	}
-	auto const&palette = m_worldStatic.palettes[0];
-	oxReturnError(ncore::loadBgTileSheet(
-				ctx, 0, m_worldStatic.tilesheet));
-	oxReturnError(ncore::loadBgPalette(ctx, 0, palette));
-	// disable all backgrounds
-	ncore::setBgStatus(ctx, 0);
-	for (auto layerNo = 0u; auto const&layer : m_worldStatic.tileMapIdx) {
-		setupLayer(ctx, layer, layerNo);
+	for (auto i = 0u; auto const&pal : m_worldStatic.palettes) {
+		oxReturnError(ncore::loadBgPalette(ctx, i, pal.palette));
+		++i;
+	}
+	oxReturnError(ncore::loadBgTileSheet(ctx, 0, m_worldStatic.tilesheets));
+	ncore::setBgStatus(ctx, 0); // disable all backgrounds
+	for (auto layerNo = 0u; auto const&layer : m_worldStatic.map) {
+		setupLayer(ctx, layerNo, layer.cbb);
 		++layerNo;
 	}
 	return {};
@@ -33,23 +33,31 @@ ox::Error World::setupDisplay(ncore::Context &ctx) const noexcept {
 
 void World::setupLayer(
 		ncore::Context &ctx,
-		ox::Vector<uint16_t> const&layer,
-		unsigned layerNo) const noexcept {
-	ncore::setBgStatus(ctx, layerNo, true);
-	ncore::setBgCbb(ctx, layerNo, 0);
-	auto x = 0;
-	auto y = 0;
-	const auto width = m_worldStatic.rows[layerNo];
-	for (auto const&tile : layer) {
-		const auto tile8 = static_cast<uint8_t>(tile);
-		ncore::setBgTile(ctx, layerNo, x + 0, y + 0, tile8 + 0);
-		ncore::setBgTile(ctx, layerNo, x + 1, y + 0, tile8 + 1);
-		ncore::setBgTile(ctx, layerNo, x + 0, y + 1, tile8 + 2);
-		ncore::setBgTile(ctx, layerNo, x + 1, y + 1, tile8 + 3);
-		x += 2;
-		if (x >= width * 2) {
-			x = 0;
-			y += 2;
+		uint_t lyr,
+		uint_t cbb) const noexcept {
+	ncore::setBgStatus(ctx, lyr, true);
+	ncore::setBgCbb(ctx, lyr, cbb);
+	for (auto y = 0; y < m_worldStatic.rows; ++y) {
+		for (auto x = 0; x < m_worldStatic.columns; ++x) {
+			auto &t = tile(m_worldStatic, lyr, static_cast<size_t>(x), static_cast<size_t>(y));
+			auto const tx = x * 2;
+			auto const ty = y * 2;
+			ncore::setBgTile(ctx, lyr, tx + 0, ty + 0, {
+				.tileIdx = static_cast<uint_t>(t.tileIdx + 0),
+				.palBank = t.palBank,
+			});
+			ncore::setBgTile(ctx, lyr, tx + 1, ty + 0, {
+				.tileIdx = static_cast<uint_t>(t.tileIdx + 1),
+				.palBank = t.palBank,
+			});
+			ncore::setBgTile(ctx, lyr, tx + 0, ty + 1, {
+				.tileIdx = static_cast<uint_t>(t.tileIdx + 2),
+				.palBank = t.palBank,
+			});
+			ncore::setBgTile(ctx, lyr, tx + 1, ty + 1, {
+				.tileIdx = static_cast<uint_t>(t.tileIdx + 3),
+				.palBank = t.palBank,
+			});
 		}
 	}
 }
diff --git a/src/jasper/modules/world/src/worlddoc.cpp b/src/jasper/modules/world/src/worlddoc.cpp
new file mode 100644
index 0000000..7b4e88b
--- /dev/null
+++ b/src/jasper/modules/world/src/worlddoc.cpp
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <jasper/world/worldstatic.hpp>
+
+namespace jasper::world {
+
+ObjectSetEntry const*objSetEntry(WorldDoc const&doc, size_t id) noexcept {
+	for (auto const&e : doc.objSets) {
+		if (e.id == id) {
+			return &e;
+		}
+	}
+	return nullptr;
+}
+
+void resize(WorldDoc &doc, ox::Size const&sz) noexcept {
+	doc.columns = sz.width;
+	doc.rows = sz.height;
+	for (auto &layer : doc.tiles) {
+		layer.resize(static_cast<size_t>(sz.height));
+		for (auto &row : layer) {
+			row.resize(static_cast<size_t>(sz.width));
+		}
+	}
+}
+
+}
diff --git a/src/jasper/modules/world/src/worldobject.cpp b/src/jasper/modules/world/src/worldobject.cpp
new file mode 100644
index 0000000..d51049c
--- /dev/null
+++ b/src/jasper/modules/world/src/worldobject.cpp
@@ -0,0 +1,17 @@
+/*
+ * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <jasper/world/worldobject.hpp>
+
+namespace jasper::world {
+
+void bgObjSetTerrainType(WorldObject &obj, TerrainType t) noexcept {
+	obj.ext1 = static_cast<uint8_t>(t);
+}
+
+TerrainType bgObjGetTerrainType(WorldObject &obj) noexcept {
+	return static_cast<TerrainType>(obj.ext1);
+}
+
+}
\ No newline at end of file
diff --git a/src/jasper/modules/world/src/worldstatic.cpp b/src/jasper/modules/world/src/worldstatic.cpp
index ab74589..8146723 100644
--- a/src/jasper/modules/world/src/worldstatic.cpp
+++ b/src/jasper/modules/world/src/worldstatic.cpp
@@ -2,10 +2,59 @@
  * Copyright 2023 - 2024 Gary Talent (gary@drinkingtea.net). All rights reserved.
  */
 
+#include <nostalgia/core/gfx.hpp>
+
 #include <jasper/world/worldstatic.hpp>
 
 namespace jasper::world {
 
+static void loadTile(ObjectCache const&objCache, TileStatic &dst, TileDoc const&src) noexcept {
+	auto const obj = objCache.obj(src.obj.worldObjectSetId, src.obj.worldObjectId).or_value({});
+	dst.palBank = src.palBank;
+	dst.tileIdx = static_cast<uint16_t>(obj.tileIdx);
+	dst.palBank = static_cast<uint8_t>(obj.palBank);
+	dst.tileType = src.type;
+	setTopEdge(dst.layerAttachments, src.topLayerAttachment);
+	setBottomEdge(dst.layerAttachments, src.bottomLayerAttachment);
+	setLeftEdge(dst.layerAttachments, src.leftLayerAttachment);
+	setRightEdge(dst.layerAttachments, src.rightLayerAttachment);
+}
 
+ox::Result<WorldStatic> loadWorldStatic(ObjectCache const&objCache, WorldDoc const&doc) noexcept {
+	auto const tileCnt =
+		static_cast<size_t>(doc.columns) * static_cast<size_t>(doc.rows);
+	WorldStatic out {
+		.tilesheets = {},
+		.palettes = {},
+		.columns = static_cast<int16_t>(doc.columns),
+		.rows = static_cast<int16_t>(doc.rows),
+		.map = {
+			{.tiles = ox::Vector<TileStatic>(tileCnt),},
+			{.tiles = ox::Vector<TileStatic>(tileCnt),},
+			{.tiles = ox::Vector<TileStatic>(tileCnt),},
+		},
+	};
+	// resources
+	out.tilesheets = objCache.tilesheets();
+	out.palettes = objCache.palettes();
+	// tiles
+	for (auto lyr = 0u; lyr < 3; ++lyr) {
+		for (auto x = 0u; x < static_cast<size_t>(out.columns); ++x) {
+			for (auto y = 0u; y < static_cast<size_t>(out.rows); ++y) {
+				auto &dst = tile(out, lyr, x, y);
+				auto &src = tile(doc, lyr, x, y);;
+				loadTile(objCache, dst, src);
+			}
+		}
+	}
+	return out;
+}
+
+bool isValid(WorldStatic const&ws) noexcept {
+	auto const tileCnt = static_cast<size_t>(ws.columns * ws.rows);
+	return ox::all_of(ws.map.begin(), ws.map.end(), [tileCnt](auto &v) {
+		return v.tiles.size() == tileCnt;
+	});
+}
 
 }
diff --git a/src/jasper/player/app.cpp b/src/jasper/player/app.cpp
index 8a5c402..91e96c6 100644
--- a/src/jasper/player/app.cpp
+++ b/src/jasper/player/app.cpp
@@ -8,12 +8,22 @@
 #include <keel/keel.hpp>
 #include <turbine/turbine.hpp>
 
+#include <nostalgia/core/core.hpp>
+
 #include <jasper/core/bootfile.hpp>
+#include <jasper/world/world.hpp>
+
+namespace ncore = nostalgia::core;
 
 namespace jasper {
-ox::Error run(turbine::Context &ctx, ox::StringView, ox::SpanView<ox::String>) noexcept {
+ox::Error run(turbine::Context &tctx, ox::StringView, ox::SpanView<ox::String>) noexcept {
 	oxOut("Jasper Player\n");
-	oxReturnError(turbine::run(ctx));
+	oxRequire(nctx, ncore::init(tctx));
+	auto constexpr worldPath = ox::FileAddress(ox::StringLiteral("/Worlds/Chester.jwld"));
+	oxRequire(worldStatic, readObj<world::WorldStatic>(keelCtx(tctx), worldPath));
+	world::World const world(*worldStatic);
+	oxReturnError(world.setupDisplay(*nctx));
+	oxReturnError(turbine::run(tctx));
 	oxOut("Exiting...\n");
 	return {};
 }
@@ -22,11 +32,14 @@ ox::Error run(turbine::Context &ctx, ox::StringView, ox::SpanView<ox::String>) n
 namespace olympic {
 
 ox::Error run(
-		[[maybe_unused]] ox::StringView project,
+		ox::StringView project,
 		[[maybe_unused]] ox::StringView appName,
 		[[maybe_unused]] ox::StringView projectDataDir,
-		[[maybe_unused]] int argc,
-		[[maybe_unused]] char const**argv) noexcept {
+		int argc,
+		char const**argv) noexcept {
+	if (argc < 2) {
+		return OxError(1, "Insufficient arguments given to olympic::run");
+	}
 	auto const path = ox::StringView(argv[1]);
 	oxRequireM(fs, keel::loadRomFs(path));
 	oxRequireM(tctx, turbine::init(std::move(fs), project));
diff --git a/src/jasper/tools/Info.plist b/src/jasper/tools/Info.plist
index 701c4c1..98bc96d 100644
--- a/src/jasper/tools/Info.plist
+++ b/src/jasper/tools/Info.plist
@@ -18,7 +18,7 @@
 	<string>APPL</string>
 
 	<key>CFBundleVersion</key>
-	<string>d2023.12.0</string>
+	<string>dev build</string>
 
 	<key>LSMinimumSystemVersion</key>
 	<string>12.0.0</string>