diff --git a/src/csg/impl/csg_types.hpp b/src/csg/impl/csg_types.hpp
index c1725fe98ec5318eeb5af4e1f7d56bba6293472b..0cf25494e37ca86160da2dca5fcc540e8b701a65 100644
--- a/src/csg/impl/csg_types.hpp
+++ b/src/csg/impl/csg_types.hpp
@@ -131,10 +131,11 @@ public:
   const matrix::Mat2d &rotation_inv() const { return m_rotation_inv; }
 };
 
+// TODO: Support twist & slices
 struct LinearExtrude {
   double height;
   bool center;
-  double twist;
+  std::tuple<double, double> scale;
   Union<Dimension::D2> group;
 };
 
diff --git a/src/csg/impl/levelset_3d.cpp b/src/csg/impl/levelset_3d.cpp
index 32161382828be434ef26c10eba42d5b325bfe140..1eee5aac2f79b256896eb6a98e088d4e9de5d487 100644
--- a/src/csg/impl/levelset_3d.cpp
+++ b/src/csg/impl/levelset_3d.cpp
@@ -129,11 +129,16 @@ double signed_distance_3d(const Cylinder &cyl, double xx, double yy,
 
 double signed_distance_3d(const LinearExtrude &lin_ext, double xx, double yy,
                           double zz) {
-  // TODO: support height, center and twist
-  double sign_z = (0 <= zz && zz <= lin_ext.height)
-                      ? 1.0
-                      : 1.0; // unused zz warning workaround
-  return sign_z * signed_distance_2d(lin_ext.group, xx, yy);
+  // TODO: Support scale
+  double ZZ = lin_ext.center ? zz + lin_ext.height / 2 : zz;
+  double sign_z = (ZZ >= 0 && ZZ <= lin_ext.height) ? -1.0 : 1.0;
+  auto dist_z = std::min(std::fabs(ZZ), std::fabs(ZZ - lin_ext.height));
+
+  auto sd_2d = signed_distance_2d(lin_ext.group, xx, yy);
+  double sign_2d = sd_2d >= 0 ? -1.0 : 1.0;
+  auto dist_2d = std::fabs(sd_2d);
+
+  return EXTERNAL_FLOW * std::max(sign_z * dist_z, sign_2d * dist_2d);
 }
 
 double signed_distance_3d(const RotateExtrude &rot_ext, double xx, double yy,
diff --git a/src/csg/impl/parser.cpp b/src/csg/impl/parser.cpp
index 22417da9231f6743a42ad16c5e8e56851a82d8e2..3e1429bd0d49a76a302b3996514f60640080ce1f 100644
--- a/src/csg/impl/parser.cpp
+++ b/src/csg/impl/parser.cpp
@@ -431,7 +431,8 @@ template <> struct action<extrude_lin> {
     auto &curr_attr = st.curr_attrs.back();
     lin_ext.height = std::get<double>(curr_attr["height"]);
     lin_ext.center = std::get<bool>(curr_attr["center"]);
-    lin_ext.twist = std::get<double>(curr_attr["twist"]);
+    auto scale = std::get<std::vector<double>>(curr_attr["scale"]);
+    lin_ext.scale = {scale[0], scale[1]};
 
     for (const auto &curr_obj : st.current_2d_group) {
       lin_ext.group.objs.push_back(curr_obj);
diff --git a/src/csg/tests/levelset/extrude.t.cpp b/src/csg/tests/levelset/extrude.t.cpp
index 5938db2f533bfdf520a8bb6d547e91e23ee99f54..6629bed95950ddcae36bd77531955bf00224360e 100644
--- a/src/csg/tests/levelset/extrude.t.cpp
+++ b/src/csg/tests/levelset/extrude.t.cpp
@@ -6,8 +6,58 @@
 
 namespace {
 
-TEST_CASE("two shape linear", "[Levelset Extrude]") {
-  auto my_lin_ext = csg::LinearExtrude();
+TEST_CASE("linear", "[Levelset Extrude]") {
+  double height = 100, radius = 10;
+  auto my_lin_ext = csg::LinearExtrude{
+      .height = 100, .center = false, .scale = {1, 1}, .group = csg::Union2D()};
+  csg::Circle my_cir{.name = std::nullopt, .radius = 10};
+
+  SECTION("Not centered") {
+    my_lin_ext.center = false;
+    my_lin_ext.group.objs.push_back(my_cir);
+    auto my_tree = std::make_shared<csg::Tree>();
+    my_tree->top.objs.push_back(my_lin_ext);
+    csg::CsgIF my_levelset(my_tree);
+
+    SECTION("Outside") {
+      CHECK_FALSE(0 < my_levelset(0, radius * 0.99, -0.01 * height));
+      CHECK_FALSE(0 < my_levelset(0, radius * 1.01, 0.01 * height));
+      CHECK_FALSE(0 < my_levelset(0, radius * 0.99, 1.01 * height));
+      CHECK_FALSE(0 < my_levelset(radius * 0.99, 0, 1.01 * height));
+    }
+    SECTION("Inside") {
+      CHECK(0 < my_levelset(0, radius * 0.99, 0.01 * height));
+      CHECK(0 < my_levelset(radius * 0.99, 0, 0.01 * height));
+      CHECK(0 < my_levelset(0, radius * 0.99, 0.99 * height));
+      CHECK(0 < my_levelset(radius * 0.99, 0, 0.99 * height));
+    }
+  }
+
+  SECTION("Centered") {
+    my_lin_ext.center = true;
+    my_lin_ext.group.objs.push_back(my_cir);
+    auto my_tree = std::make_shared<csg::Tree>();
+    my_tree->top.objs.push_back(my_lin_ext);
+    csg::CsgIF my_levelset(my_tree);
+
+    SECTION("Outside") {
+      CHECK_FALSE(0 < my_levelset(0, radius * 0.99, -1.01 * height / 2));
+      CHECK_FALSE(0 < my_levelset(0, radius * 1.01, 0.01 * height));
+      CHECK_FALSE(0 < my_levelset(0, radius * 0.99, 1.01 * height / 2));
+      CHECK_FALSE(0 < my_levelset(radius * 0.99, 0, 1.01 * height / 2));
+    }
+    SECTION("Inside") {
+      CHECK(0 < my_levelset(0, radius * 0.99, -0.99 * height / 2));
+      CHECK(0 < my_levelset(radius * 0.99, 0, 0.01 * height / 2));
+      CHECK(0 < my_levelset(0, radius * 0.99, 0.99 * height / 2));
+      CHECK(0 < my_levelset(radius * 0.99, 0, 0.99 * height / 2));
+    }
+  }
+}
+
+TEST_CASE("two shape linear extrude", "[Levelset Extrude]") {
+  auto my_lin_ext = csg::LinearExtrude{
+      .height = 100, .center = true, .scale = {1, 1}, .group = csg::Union2D()};
 
   csg::Circle my_cir{.name = std::nullopt, .radius = 1};
   my_lin_ext.group.objs.push_back(my_cir);
@@ -24,6 +74,8 @@ TEST_CASE("two shape linear", "[Levelset Extrude]") {
   SECTION("Outside") {
     CHECK_FALSE(0 < my_levelset(0, 2, 0));
     CHECK_FALSE(0 < my_levelset(-4, 0, 0));
+    CHECK_FALSE(0 < my_levelset(3.5, 0, 51));
+    CHECK_FALSE(0 < my_levelset(3.5, 0, -51));
   }
   SECTION("Inside") {
     CHECK(0 < my_levelset(0, 0, 0));
@@ -31,8 +83,8 @@ TEST_CASE("two shape linear", "[Levelset Extrude]") {
     CHECK(0 < my_levelset(-0.5, 0, 0));
     CHECK(0 < my_levelset(4.5, 0, 0));
     CHECK(0 < my_levelset(3.5, 0, 0));
-    CHECK(0 < my_levelset(3.5, 0, 100));
-    CHECK(0 < my_levelset(3.5, 0, -100));
+    CHECK(0 < my_levelset(3.5, 0, 49));
+    CHECK(0 < my_levelset(3.5, 0, -49));
   }
 }
 
diff --git a/src/csg/tests/parser/extrude.t.cpp b/src/csg/tests/parser/extrude.t.cpp
index 48ab4e01c0de0f8d2273eab3fa7b8353576b2bb7..3cebfeff4a2038a452ea8d4b85a5e2aba3dd9a33 100644
--- a/src/csg/tests/parser/extrude.t.cpp
+++ b/src/csg/tests/parser/extrude.t.cpp
@@ -10,7 +10,7 @@ TEST_CASE("linear extrude", "[csg]") {
 linear_extrude(
 height = 10,
 center = true,
-twist = 0
+scale = [10,1]
 ) {
     circle(r = 1);
 }
@@ -19,7 +19,10 @@ twist = 0
   CHECK(lin_ext.group.objs.size() == 1);
   CHECK(lin_ext.height == 10);
   CHECK(lin_ext.center == true);
-  CHECK(lin_ext.twist == 0);
+
+  auto [Sx, Sy] = lin_ext.scale;
+  CHECK(Sx == 10);
+  CHECK(Sy == 1);
 
   auto cir = std::get<csg::Circle>(lin_ext.group.objs.at(0));
   CHECK(cir.radius == 1);
@@ -48,7 +51,7 @@ TEST_CASE("extrude two shapes", "[csg]") {
 linear_extrude(
 height = 10,
 center = true,
-twist = 0
+scale = [5, 3]
 ) {
     circle(r = 1);
     square(size = [2, 2], center = false);
@@ -59,7 +62,10 @@ twist = 0
   CHECK(lin_ext.group.objs.size() == 2);
   CHECK(lin_ext.height == 10);
   CHECK(lin_ext.center == true);
-  CHECK(lin_ext.twist == 0);
+
+  auto [Sx, Sy] = lin_ext.scale;
+  CHECK(Sx == 5);
+  CHECK(Sy == 3);
 
   auto cir = std::get<csg::Circle>(lin_ext.group.objs.at(0));
   CHECK(cir.radius == 1);
@@ -72,7 +78,7 @@ twist = 0
 
 TEST_CASE("extrude with mulmatrix", "[csg]") {
   auto st = *csg::parse_csg(R"(
-linear_extrude(height = 10, center = false, twist = 5) {
+linear_extrude(height = 10, center = false, scale = [5, 3]) {
 	circle(r = 2);
 	multmatrix([[1, 0, 0, 5], [0, 1, 0, 5], [0, 0, 1, 0], [0, 0, 0, 1]]) {
 		square(size = [4, 5], center = false);
@@ -84,7 +90,10 @@ linear_extrude(height = 10, center = false, twist = 5) {
   CHECK(lin_ext.group.objs.size() == 2);
   CHECK(lin_ext.height == 10);
   CHECK(lin_ext.center == false);
-  CHECK(lin_ext.twist == 5);
+
+  auto [Sx, Sy] = lin_ext.scale;
+  CHECK(Sx == 5);
+  CHECK(Sy == 3);
 
   auto cir = std::get<csg::Circle>(lin_ext.group.objs.at(0));
   CHECK(cir.radius == 2);
@@ -99,11 +108,12 @@ linear_extrude(height = 10, center = false, twist = 5) {
   auto [xx, yy] = sq.size;
   CHECK(xx == 4);
   CHECK(yy == 5);
+  CHECK(sq.center == false);
 }
 
 TEST_CASE("extrude with 3D object", "[csg]") {
   auto st = csg::parse_csg(R"(
-linear_extrude(height = 10, center = false, twist = 5) {
+linear_extrude(height = 10, center = false, scale = [5, 5]) {
 	multmatrix([[1, 0, 0, 5], [0, 1, 0, 5], [0, 0, 1, 0], [0, 0, 0, 1]]) {
 		sphere(r = 8);
 	}