diff --git a/CMakeLists.txt b/CMakeLists.txt
index b183690..a260110 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -51,8 +51,8 @@ set(PHYSFS_ARCHIVE_QPAK OFF)
 set(PHYSFS_ARCHIVE_SLB OFF)
 set(PHYSFS_ARCHIVE_ISO9660 OFF)
 set(PHYSFS_ARCHIVE_VDF OFF)
-add_subdirectory(third-party/physfs SYSTEM)
-add_subdirectory(third-party/libxm SYSTEM)
+add_subdirectory(third-party/physfs ${CMAKE_CURRENT_BINARY_DIR}/third-party/physfs SYSTEM)
+add_subdirectory(third-party/libxm ${CMAKE_CURRENT_BINARY_DIR}/third-party/libxm SYSTEM)
 
 
 if(LINUX)
diff --git a/apps/platformer/CMakeLists.txt b/apps/platformer/CMakeLists.txt
index 1c3d3ec..9298f7a 100644
--- a/apps/platformer/CMakeLists.txt
+++ b/apps/platformer/CMakeLists.txt
@@ -6,10 +6,7 @@ if(NOT CMAKE_BUILD_TYPE)
         set(CMAKE_BUILD_TYPE Debug)
 endif()
 
-# add root townengine cmake file
-if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
-        add_subdirectory(../../ ../../../.build)
-endif()
+add_subdirectory($ENV{TWNROOT} $ENV{TWNBUILDDIR})
 
 set(SOURCE_FILES
         game.c
diff --git a/apps/scenery/CMakeLists.txt b/apps/scenery/CMakeLists.txt
index 2151142..7f7e4bb 100644
--- a/apps/scenery/CMakeLists.txt
+++ b/apps/scenery/CMakeLists.txt
@@ -6,10 +6,7 @@ if(NOT CMAKE_BUILD_TYPE)
         set(CMAKE_BUILD_TYPE Debug)
 endif()
 
-# add root townengine cmake file
-if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
-        add_subdirectory(../../ ../../../.build)
-endif()
+add_subdirectory($ENV{TWNROOT} $ENV{TWNBUILDDIR})
 
 set(SOURCE_FILES
         game.c
diff --git a/apps/scenery/build.sh b/apps/scenery/build.sh
deleted file mode 100755
index aefa755..0000000
--- a/apps/scenery/build.sh
+++ /dev/null
@@ -1,7 +0,0 @@
-#!/bin/env sh
-
-if [ $1 = "web" ]; then
-    emcmake cmake -B .build-web "${@:2}" && cmake --build .build-web
-else
-    cmake -B .build "$@" && cmake --build .build
-fi
diff --git a/apps/template/CMakeLists.txt b/apps/template/CMakeLists.txt
index 3a34666..b8110d3 100644
--- a/apps/template/CMakeLists.txt
+++ b/apps/template/CMakeLists.txt
@@ -6,10 +6,7 @@ if(NOT CMAKE_BUILD_TYPE)
         set(CMAKE_BUILD_TYPE Debug)
 endif()
 
-# add root townengine cmake file
-if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
-        add_subdirectory(../../ ../../../.build)
-endif()
+add_subdirectory($ENV{TWNROOT} $ENV{TWNBUILDDIR})
 
 set(SOURCE_FILES
         game.c
diff --git a/apps/template/build.sh b/apps/template/build.sh
deleted file mode 100755
index 45ab8a7..0000000
--- a/apps/template/build.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/bin/env sh
-
-cmake -B .build "$@" && cmake --build .build
diff --git a/apps/platformer/build.sh b/tools/build.sh
similarity index 84%
rename from apps/platformer/build.sh
rename to tools/build.sh
index aefa755..d7f57c9 100755
--- a/apps/platformer/build.sh
+++ b/tools/build.sh
@@ -1,6 +1,6 @@
 #!/bin/env sh
 
-if [ $1 = "web" ]; then
+if [ "$1" = "web" ]; then
     emcmake cmake -B .build-web "${@:2}" && cmake --build .build-web
 else
     cmake -B .build "$@" && cmake --build .build
diff --git a/tools/twn b/tools/twn
new file mode 100755
index 0000000..cb70d7f
--- /dev/null
+++ b/tools/twn
@@ -0,0 +1,15 @@
+#!/bin/env sh
+# townengine tooling interface
+
+set +e
+
+toolpath="$(dirname -- "${BASH_SOURCE[0]}")"
+export TWNROOT=$(realpath "$toolpath"/../)
+export TWNBUILDDIR=$(realpath "$toolpath"/../.build)
+
+case "$1" in
+    build ) "$toolpath"/build.sh
+            ;;
+    *     ) echo "Unknown command."
+            ;;
+esac