From 49f8de6924eccc0e53e80c5c76c834e0b29ab321 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 16:38:18 +0100
Subject: [PATCH 01/16] Rename `kernel::shape` to `operations`

The near-collision with `kernel::shape` has always been unfortunate, so
renaming one of them is a good idea. I think `operations` is a good name
for the module, as that's what it's focused on: Translating the
operations from the `fj` crate into something the kernel understands.
---
 fj-app/src/kernel/mod.rs                                  | 2 +-
 fj-app/src/kernel/{shapes => operations}/circle.rs        | 0
 fj-app/src/kernel/{shapes => operations}/difference_2d.rs | 0
 fj-app/src/kernel/{shapes => operations}/group.rs         | 0
 fj-app/src/kernel/{shapes => operations}/mod.rs           | 0
 fj-app/src/kernel/{shapes => operations}/sketch.rs        | 0
 fj-app/src/kernel/{shapes => operations}/sweep.rs         | 0
 fj-app/src/kernel/{shapes => operations}/transform.rs     | 0
 fj-app/src/main.rs                                        | 2 +-
 9 files changed, 2 insertions(+), 2 deletions(-)
 rename fj-app/src/kernel/{shapes => operations}/circle.rs (100%)
 rename fj-app/src/kernel/{shapes => operations}/difference_2d.rs (100%)
 rename fj-app/src/kernel/{shapes => operations}/group.rs (100%)
 rename fj-app/src/kernel/{shapes => operations}/mod.rs (100%)
 rename fj-app/src/kernel/{shapes => operations}/sketch.rs (100%)
 rename fj-app/src/kernel/{shapes => operations}/sweep.rs (100%)
 rename fj-app/src/kernel/{shapes => operations}/transform.rs (100%)

diff --git a/fj-app/src/kernel/mod.rs b/fj-app/src/kernel/mod.rs
index 2635f15f3..d6a5cfc95 100644
--- a/fj-app/src/kernel/mod.rs
+++ b/fj-app/src/kernel/mod.rs
@@ -78,6 +78,6 @@
 
 pub mod algorithms;
 pub mod geometry;
+pub mod operations;
 pub mod shape;
-pub mod shapes;
 pub mod topology;
diff --git a/fj-app/src/kernel/shapes/circle.rs b/fj-app/src/kernel/operations/circle.rs
similarity index 100%
rename from fj-app/src/kernel/shapes/circle.rs
rename to fj-app/src/kernel/operations/circle.rs
diff --git a/fj-app/src/kernel/shapes/difference_2d.rs b/fj-app/src/kernel/operations/difference_2d.rs
similarity index 100%
rename from fj-app/src/kernel/shapes/difference_2d.rs
rename to fj-app/src/kernel/operations/difference_2d.rs
diff --git a/fj-app/src/kernel/shapes/group.rs b/fj-app/src/kernel/operations/group.rs
similarity index 100%
rename from fj-app/src/kernel/shapes/group.rs
rename to fj-app/src/kernel/operations/group.rs
diff --git a/fj-app/src/kernel/shapes/mod.rs b/fj-app/src/kernel/operations/mod.rs
similarity index 100%
rename from fj-app/src/kernel/shapes/mod.rs
rename to fj-app/src/kernel/operations/mod.rs
diff --git a/fj-app/src/kernel/shapes/sketch.rs b/fj-app/src/kernel/operations/sketch.rs
similarity index 100%
rename from fj-app/src/kernel/shapes/sketch.rs
rename to fj-app/src/kernel/operations/sketch.rs
diff --git a/fj-app/src/kernel/shapes/sweep.rs b/fj-app/src/kernel/operations/sweep.rs
similarity index 100%
rename from fj-app/src/kernel/shapes/sweep.rs
rename to fj-app/src/kernel/operations/sweep.rs
diff --git a/fj-app/src/kernel/shapes/transform.rs b/fj-app/src/kernel/operations/transform.rs
similarity index 100%
rename from fj-app/src/kernel/shapes/transform.rs
rename to fj-app/src/kernel/operations/transform.rs
diff --git a/fj-app/src/main.rs b/fj-app/src/main.rs
index 572ff6bce..08fc99086 100644
--- a/fj-app/src/main.rs
+++ b/fj-app/src/main.rs
@@ -30,7 +30,7 @@ use crate::{
     camera::Camera,
     config::Config,
     graphics::{DrawConfig, Renderer},
-    kernel::shapes::ToShape as _,
+    kernel::operations::ToShape as _,
     mesh::MeshMaker,
     model::Model,
     window::Window,

From 48db26569a637ada1ddb6617fabc306e58a98e06 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 16:42:20 +0100
Subject: [PATCH 02/16] Move `kernel::operations` to crate root

I'm about to extract the kernel into a separate crate, and I don't want
this module to be a part of it. Nothing else in the kernel depends on
it, and it's a different thing, I think: It's the connection between the
kernel and the operations in the `fj` crate.

It's totally conceivable that someone would want to use the kernel,
without wanting to be bound to the `fj` operations. So both from a
software architecture and from a use case perspective, I think this
module should be a separate thing.
---
 fj-app/src/kernel/mod.rs                            | 1 -
 fj-app/src/main.rs                                  | 3 ++-
 fj-app/src/{kernel => }/operations/circle.rs        | 0
 fj-app/src/{kernel => }/operations/difference_2d.rs | 0
 fj-app/src/{kernel => }/operations/group.rs         | 0
 fj-app/src/{kernel => }/operations/mod.rs           | 2 +-
 fj-app/src/{kernel => }/operations/sketch.rs        | 0
 fj-app/src/{kernel => }/operations/sweep.rs         | 0
 fj-app/src/{kernel => }/operations/transform.rs     | 0
 9 files changed, 3 insertions(+), 3 deletions(-)
 rename fj-app/src/{kernel => }/operations/circle.rs (100%)
 rename fj-app/src/{kernel => }/operations/difference_2d.rs (100%)
 rename fj-app/src/{kernel => }/operations/group.rs (100%)
 rename fj-app/src/{kernel => }/operations/mod.rs (98%)
 rename fj-app/src/{kernel => }/operations/sketch.rs (100%)
 rename fj-app/src/{kernel => }/operations/sweep.rs (100%)
 rename fj-app/src/{kernel => }/operations/transform.rs (100%)

diff --git a/fj-app/src/kernel/mod.rs b/fj-app/src/kernel/mod.rs
index d6a5cfc95..9a647f743 100644
--- a/fj-app/src/kernel/mod.rs
+++ b/fj-app/src/kernel/mod.rs
@@ -78,6 +78,5 @@
 
 pub mod algorithms;
 pub mod geometry;
-pub mod operations;
 pub mod shape;
 pub mod topology;
diff --git a/fj-app/src/main.rs b/fj-app/src/main.rs
index 08fc99086..d1cc8aa1e 100644
--- a/fj-app/src/main.rs
+++ b/fj-app/src/main.rs
@@ -6,6 +6,7 @@ mod input;
 mod kernel;
 mod mesh;
 mod model;
+mod operations;
 mod window;
 
 use std::collections::HashSet;
@@ -30,9 +31,9 @@ use crate::{
     camera::Camera,
     config::Config,
     graphics::{DrawConfig, Renderer},
-    kernel::operations::ToShape as _,
     mesh::MeshMaker,
     model::Model,
+    operations::ToShape as _,
     window::Window,
 };
 
diff --git a/fj-app/src/kernel/operations/circle.rs b/fj-app/src/operations/circle.rs
similarity index 100%
rename from fj-app/src/kernel/operations/circle.rs
rename to fj-app/src/operations/circle.rs
diff --git a/fj-app/src/kernel/operations/difference_2d.rs b/fj-app/src/operations/difference_2d.rs
similarity index 100%
rename from fj-app/src/kernel/operations/difference_2d.rs
rename to fj-app/src/operations/difference_2d.rs
diff --git a/fj-app/src/kernel/operations/group.rs b/fj-app/src/operations/group.rs
similarity index 100%
rename from fj-app/src/kernel/operations/group.rs
rename to fj-app/src/operations/group.rs
diff --git a/fj-app/src/kernel/operations/mod.rs b/fj-app/src/operations/mod.rs
similarity index 98%
rename from fj-app/src/kernel/operations/mod.rs
rename to fj-app/src/operations/mod.rs
index e7b00773d..7e86ea2ef 100644
--- a/fj-app/src/kernel/operations/mod.rs
+++ b/fj-app/src/operations/mod.rs
@@ -8,7 +8,7 @@ pub mod transform;
 use fj_debug::DebugInfo;
 use fj_math::{Aabb, Scalar};
 
-use super::shape::Shape;
+use crate::kernel::shape::Shape;
 
 /// Implemented by all shapes
 pub trait ToShape {
diff --git a/fj-app/src/kernel/operations/sketch.rs b/fj-app/src/operations/sketch.rs
similarity index 100%
rename from fj-app/src/kernel/operations/sketch.rs
rename to fj-app/src/operations/sketch.rs
diff --git a/fj-app/src/kernel/operations/sweep.rs b/fj-app/src/operations/sweep.rs
similarity index 100%
rename from fj-app/src/kernel/operations/sweep.rs
rename to fj-app/src/operations/sweep.rs
diff --git a/fj-app/src/kernel/operations/transform.rs b/fj-app/src/operations/transform.rs
similarity index 100%
rename from fj-app/src/kernel/operations/transform.rs
rename to fj-app/src/operations/transform.rs

From eccff5d725a352bbee200a897f41da317cf4f49c Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 16:59:52 +0100
Subject: [PATCH 03/16] Extract `fj-kernel` from `fj-app`

---
 Cargo.lock                                    | 27 +++++++++++-----
 Cargo.toml                                    |  2 ++
 fj-app/Cargo.toml                             |  9 +++---
 fj-app/src/main.rs                            |  1 -
 fj-app/src/operations/circle.rs               |  5 ++-
 fj-app/src/operations/difference_2d.rs        |  5 ++-
 fj-app/src/operations/group.rs                |  5 ++-
 fj-app/src/operations/mod.rs                  |  3 +-
 fj-app/src/operations/sketch.rs               |  5 ++-
 fj-app/src/operations/sweep.rs                |  3 +-
 fj-app/src/operations/transform.rs            |  3 +-
 fj-kernel/Cargo.toml                          | 31 +++++++++++++++++++
 .../src}/algorithms/approximation.rs          |  4 +--
 .../src}/algorithms/mod.rs                    |  0
 .../src}/algorithms/sweep.rs                  |  4 +--
 .../src}/algorithms/triangulation.rs          |  2 +-
 .../src}/geometry/curves/circle.rs            |  0
 .../src}/geometry/curves/line.rs              |  0
 .../src}/geometry/curves/mod.rs               |  0
 .../kernel => fj-kernel/src}/geometry/mod.rs  |  0
 .../src}/geometry/points.rs                   |  0
 .../src}/geometry/surfaces/mod.rs             |  2 +-
 .../src}/geometry/surfaces/swept.rs           |  6 ++--
 .../src/kernel/mod.rs => fj-kernel/src/lib.rs |  0
 .../src}/shape/geometry.rs                    |  2 +-
 .../kernel => fj-kernel/src}/shape/handle.rs  |  0
 .../kernel => fj-kernel/src}/shape/iter.rs    |  0
 .../src/kernel => fj-kernel/src}/shape/mod.rs |  0
 .../src}/shape/topology.rs                    |  4 +--
 .../src}/shape/validate.rs                    |  2 +-
 .../src}/topology/edges.rs                    |  2 +-
 .../src}/topology/faces.rs                    |  2 +-
 .../kernel => fj-kernel/src}/topology/mod.rs  |  0
 .../src}/topology/vertices.rs                 |  2 +-
 34 files changed, 84 insertions(+), 47 deletions(-)
 create mode 100644 fj-kernel/Cargo.toml
 rename {fj-app/src/kernel => fj-kernel/src}/algorithms/approximation.rs (99%)
 rename {fj-app/src/kernel => fj-kernel/src}/algorithms/mod.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/algorithms/sweep.rs (99%)
 rename {fj-app/src/kernel => fj-kernel/src}/algorithms/triangulation.rs (98%)
 rename {fj-app/src/kernel => fj-kernel/src}/geometry/curves/circle.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/geometry/curves/line.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/geometry/curves/mod.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/geometry/mod.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/geometry/points.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/geometry/surfaces/mod.rs (98%)
 rename {fj-app/src/kernel => fj-kernel/src}/geometry/surfaces/swept.rs (96%)
 rename fj-app/src/kernel/mod.rs => fj-kernel/src/lib.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/shape/geometry.rs (99%)
 rename {fj-app/src/kernel => fj-kernel/src}/shape/handle.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/shape/iter.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/shape/mod.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/shape/topology.rs (99%)
 rename {fj-app/src/kernel => fj-kernel/src}/shape/validate.rs (99%)
 rename {fj-app/src/kernel => fj-kernel/src}/topology/edges.rs (98%)
 rename {fj-app/src/kernel => fj-kernel/src}/topology/faces.rs (99%)
 rename {fj-app/src/kernel => fj-kernel/src}/topology/mod.rs (100%)
 rename {fj-app/src/kernel => fj-kernel/src}/topology/vertices.rs (97%)

diff --git a/Cargo.lock b/Cargo.lock
index 02bd332ec..5de234255 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -626,23 +626,19 @@ name = "fj-app"
 version = "0.5.0"
 dependencies = [
  "anyhow",
- "approx 0.5.1",
  "bytemuck",
  "clap",
  "figment",
  "fj",
  "fj-debug",
+ "fj-kernel",
  "fj-math",
  "futures",
  "libloading",
- "map-macro",
  "nalgebra",
  "notify",
- "parking_lot 0.12.0",
- "parry2d-f64",
  "parry3d-f64",
  "serde",
- "spade",
  "thiserror",
  "threemf",
  "tracing",
@@ -659,6 +655,23 @@ dependencies = [
  "parry3d-f64",
 ]
 
+[[package]]
+name = "fj-kernel"
+version = "0.5.0"
+dependencies = [
+ "anyhow",
+ "approx 0.5.1",
+ "fj-debug",
+ "fj-math",
+ "map-macro",
+ "nalgebra",
+ "parking_lot 0.12.0",
+ "parry2d-f64",
+ "parry3d-f64",
+ "spade",
+ "thiserror",
+]
+
 [[package]]
 name = "fj-math"
 version = "0.5.0"
@@ -1129,9 +1142,9 @@ dependencies = [
 
 [[package]]
 name = "map-macro"
-version = "0.2.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b3dec3b229449b1a54bd96dc32108086263d6830624e576dc0e6c80e619a0130"
+checksum = "9d5b0858fc6e216d2d6222d661021d9b184550acd757fbd80a8f86224069422c"
 
 [[package]]
 name = "matchers"
diff --git a/Cargo.toml b/Cargo.toml
index a672aadfe..961bb9076 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,6 +4,7 @@ members = [
     "fj",
     "fj-app",
     "fj-debug",
+    "fj-kernel",
     "fj-math",
 
     "models/cuboid",
@@ -16,5 +17,6 @@ members = [
 default-members = [
     "fj-app",
     "fj-debug",
+    "fj-kernel",
     "fj-math",
 ]
diff --git a/fj-app/Cargo.toml b/fj-app/Cargo.toml
index fd648d68c..663310e2e 100644
--- a/fj-app/Cargo.toml
+++ b/fj-app/Cargo.toml
@@ -13,17 +13,12 @@ categories  = ["mathematics", "rendering"]
 
 [dependencies]
 anyhow      = "1.0.56"
-approx      = "0.5.1"
 bytemuck    = "1.8.0"
 futures     = "0.3.21"
 libloading  = "0.7.2"
-map-macro   = "0.2.0"
 nalgebra    = "0.30.0"
 notify      = "5.0.0-pre.14"
-parking_lot = "0.12.0"
-parry2d-f64 = "0.8.0"
 parry3d-f64 = "0.8.0"
-spade       = "2.0.0"
 thiserror   = "1.0.30"
 threemf     = "0.2.0"
 tracing     = "0.1.32"
@@ -47,6 +42,10 @@ path    = "../fj"
 version = "0.5.0"
 path    = "../fj-debug"
 
+[dependencies.fj-kernel]
+version = "0.5.0"
+path    = "../fj-kernel"
+
 [dependencies.fj-math]
 version = "0.5.0"
 path    = "../fj-math"
diff --git a/fj-app/src/main.rs b/fj-app/src/main.rs
index d1cc8aa1e..39a547cf4 100644
--- a/fj-app/src/main.rs
+++ b/fj-app/src/main.rs
@@ -3,7 +3,6 @@ mod camera;
 mod config;
 mod graphics;
 mod input;
-mod kernel;
 mod mesh;
 mod model;
 mod operations;
diff --git a/fj-app/src/operations/circle.rs b/fj-app/src/operations/circle.rs
index 98e9e8d32..c495e6a87 100644
--- a/fj-app/src/operations/circle.rs
+++ b/fj-app/src/operations/circle.rs
@@ -1,11 +1,10 @@
 use fj_debug::DebugInfo;
-use fj_math::{Aabb, Point, Scalar};
-
-use crate::kernel::{
+use fj_kernel::{
     geometry::Surface,
     shape::Shape,
     topology::{edges::Cycle, faces::Face},
 };
+use fj_math::{Aabb, Point, Scalar};
 
 use super::ToShape;
 
diff --git a/fj-app/src/operations/difference_2d.rs b/fj-app/src/operations/difference_2d.rs
index b44f7b151..265804849 100644
--- a/fj-app/src/operations/difference_2d.rs
+++ b/fj-app/src/operations/difference_2d.rs
@@ -1,9 +1,7 @@
 use std::collections::HashMap;
 
 use fj_debug::DebugInfo;
-use fj_math::{Aabb, Scalar};
-
-use crate::kernel::{
+use fj_kernel::{
     shape::Shape,
     topology::{
         edges::{Cycle, Edge},
@@ -11,6 +9,7 @@ use crate::kernel::{
         vertices::Vertex,
     },
 };
+use fj_math::{Aabb, Scalar};
 
 use super::ToShape;
 
diff --git a/fj-app/src/operations/group.rs b/fj-app/src/operations/group.rs
index 2c44b42b4..2d40de3e2 100644
--- a/fj-app/src/operations/group.rs
+++ b/fj-app/src/operations/group.rs
@@ -1,9 +1,7 @@
 use std::collections::HashMap;
 
 use fj_debug::DebugInfo;
-use fj_math::{Aabb, Scalar};
-
-use crate::kernel::{
+use fj_kernel::{
     shape::Shape,
     topology::{
         edges::{Cycle, Edge},
@@ -11,6 +9,7 @@ use crate::kernel::{
         vertices::Vertex,
     },
 };
+use fj_math::{Aabb, Scalar};
 
 use super::ToShape;
 
diff --git a/fj-app/src/operations/mod.rs b/fj-app/src/operations/mod.rs
index 7e86ea2ef..0c180610e 100644
--- a/fj-app/src/operations/mod.rs
+++ b/fj-app/src/operations/mod.rs
@@ -6,10 +6,9 @@ pub mod sweep;
 pub mod transform;
 
 use fj_debug::DebugInfo;
+use fj_kernel::shape::Shape;
 use fj_math::{Aabb, Scalar};
 
-use crate::kernel::shape::Shape;
-
 /// Implemented by all shapes
 pub trait ToShape {
     /// Compute the boundary representation of the shape
diff --git a/fj-app/src/operations/sketch.rs b/fj-app/src/operations/sketch.rs
index 8deb59928..bcd4b9baf 100644
--- a/fj-app/src/operations/sketch.rs
+++ b/fj-app/src/operations/sketch.rs
@@ -1,11 +1,10 @@
 use fj_debug::DebugInfo;
-use fj_math::{Aabb, Point, Scalar};
-
-use crate::kernel::{
+use fj_kernel::{
     geometry::Surface,
     shape::Shape,
     topology::{edges::Cycle, faces::Face, vertices::Vertex},
 };
+use fj_math::{Aabb, Point, Scalar};
 
 use super::ToShape;
 
diff --git a/fj-app/src/operations/sweep.rs b/fj-app/src/operations/sweep.rs
index 0ddc6d80f..cf8099c92 100644
--- a/fj-app/src/operations/sweep.rs
+++ b/fj-app/src/operations/sweep.rs
@@ -1,8 +1,7 @@
 use fj_debug::DebugInfo;
+use fj_kernel::{algorithms::sweep::sweep_shape, shape::Shape};
 use fj_math::{Aabb, Scalar, Vector};
 
-use crate::kernel::{algorithms::sweep::sweep_shape, shape::Shape};
-
 use super::ToShape;
 
 impl ToShape for fj::Sweep {
diff --git a/fj-app/src/operations/transform.rs b/fj-app/src/operations/transform.rs
index 6a2ffd1f1..f297e0122 100644
--- a/fj-app/src/operations/transform.rs
+++ b/fj-app/src/operations/transform.rs
@@ -1,9 +1,8 @@
 use fj_debug::DebugInfo;
+use fj_kernel::shape::Shape;
 use fj_math::{Aabb, Scalar, Transform};
 use parry3d_f64::math::Isometry;
 
-use crate::kernel::shape::Shape;
-
 use super::ToShape;
 
 impl ToShape for fj::Transform {
diff --git a/fj-kernel/Cargo.toml b/fj-kernel/Cargo.toml
new file mode 100644
index 000000000..c2fa657c2
--- /dev/null
+++ b/fj-kernel/Cargo.toml
@@ -0,0 +1,31 @@
+[package]
+name    = "fj-kernel"
+version = "0.5.0"
+edition = "2021"
+
+description = "The world needs another CAD program."
+readme      = "../README.md"
+repository  = "https://github.com/hannobraun/fornjot"
+license     = "0BSD"
+keywords    = ["cad", "programmatic", "code-cad"]
+categories  = ["mathematics"]
+
+
+[dependencies]
+anyhow      = "1.0.56"
+approx      = "0.5.1"
+map-macro   = "0.2.0"
+nalgebra    = "0.30.0"
+parking_lot = "0.12.0"
+parry2d-f64 = "0.8.0"
+parry3d-f64 = "0.8.0"
+spade       = "2.0.0"
+thiserror   = "1.0.30"
+
+[dependencies.fj-debug]
+version = "0.5.0"
+path    = "../fj-debug"
+
+[dependencies.fj-math]
+version = "0.5.0"
+path    = "../fj-math"
diff --git a/fj-app/src/kernel/algorithms/approximation.rs b/fj-kernel/src/algorithms/approximation.rs
similarity index 99%
rename from fj-app/src/kernel/algorithms/approximation.rs
rename to fj-kernel/src/algorithms/approximation.rs
index 60baff4e2..138540cdf 100644
--- a/fj-app/src/kernel/algorithms/approximation.rs
+++ b/fj-kernel/src/algorithms/approximation.rs
@@ -2,7 +2,7 @@ use std::collections::HashSet;
 
 use fj_math::{Point, Scalar, Segment};
 
-use crate::kernel::topology::{
+use crate::topology::{
     edges::{Cycle, Edge},
     faces::Face,
     vertices::Vertex,
@@ -134,7 +134,7 @@ mod tests {
     use fj_math::{Point, Scalar, Segment};
     use map_macro::set;
 
-    use crate::kernel::{
+    use crate::{
         geometry::Surface,
         shape::Shape,
         topology::{edges::Cycle, faces::Face, vertices::Vertex},
diff --git a/fj-app/src/kernel/algorithms/mod.rs b/fj-kernel/src/algorithms/mod.rs
similarity index 100%
rename from fj-app/src/kernel/algorithms/mod.rs
rename to fj-kernel/src/algorithms/mod.rs
diff --git a/fj-app/src/kernel/algorithms/sweep.rs b/fj-kernel/src/algorithms/sweep.rs
similarity index 99%
rename from fj-app/src/kernel/algorithms/sweep.rs
rename to fj-kernel/src/algorithms/sweep.rs
index 09d5c8f66..b1723811e 100644
--- a/fj-app/src/kernel/algorithms/sweep.rs
+++ b/fj-kernel/src/algorithms/sweep.rs
@@ -2,7 +2,7 @@ use std::collections::HashMap;
 
 use fj_math::{Scalar, Transform, Triangle, Vector};
 
-use crate::kernel::{
+use crate::{
     geometry::{surfaces::Swept, Surface},
     shape::{Handle, Shape},
     topology::{
@@ -323,7 +323,7 @@ impl Relation {
 mod tests {
     use fj_math::{Point, Scalar, Vector};
 
-    use crate::kernel::{
+    use crate::{
         geometry::{surfaces::Swept, Surface},
         shape::{Handle, Shape},
         topology::{edges::Cycle, faces::Face, vertices::Vertex},
diff --git a/fj-app/src/kernel/algorithms/triangulation.rs b/fj-kernel/src/algorithms/triangulation.rs
similarity index 98%
rename from fj-app/src/kernel/algorithms/triangulation.rs
rename to fj-kernel/src/algorithms/triangulation.rs
index 435fbf65d..fcd23dd50 100644
--- a/fj-app/src/kernel/algorithms/triangulation.rs
+++ b/fj-kernel/src/algorithms/triangulation.rs
@@ -2,7 +2,7 @@ use fj_math::Scalar;
 use parry2d_f64::utils::point_in_triangle::{corner_direction, Orientation};
 use spade::HasPosition;
 
-use crate::kernel::geometry;
+use crate::geometry;
 
 /// Create a Delaunay triangulation of all points
 pub fn triangulate(
diff --git a/fj-app/src/kernel/geometry/curves/circle.rs b/fj-kernel/src/geometry/curves/circle.rs
similarity index 100%
rename from fj-app/src/kernel/geometry/curves/circle.rs
rename to fj-kernel/src/geometry/curves/circle.rs
diff --git a/fj-app/src/kernel/geometry/curves/line.rs b/fj-kernel/src/geometry/curves/line.rs
similarity index 100%
rename from fj-app/src/kernel/geometry/curves/line.rs
rename to fj-kernel/src/geometry/curves/line.rs
diff --git a/fj-app/src/kernel/geometry/curves/mod.rs b/fj-kernel/src/geometry/curves/mod.rs
similarity index 100%
rename from fj-app/src/kernel/geometry/curves/mod.rs
rename to fj-kernel/src/geometry/curves/mod.rs
diff --git a/fj-app/src/kernel/geometry/mod.rs b/fj-kernel/src/geometry/mod.rs
similarity index 100%
rename from fj-app/src/kernel/geometry/mod.rs
rename to fj-kernel/src/geometry/mod.rs
diff --git a/fj-app/src/kernel/geometry/points.rs b/fj-kernel/src/geometry/points.rs
similarity index 100%
rename from fj-app/src/kernel/geometry/points.rs
rename to fj-kernel/src/geometry/points.rs
diff --git a/fj-app/src/kernel/geometry/surfaces/mod.rs b/fj-kernel/src/geometry/surfaces/mod.rs
similarity index 98%
rename from fj-app/src/kernel/geometry/surfaces/mod.rs
rename to fj-kernel/src/geometry/surfaces/mod.rs
index 1d060d0a2..adbdb2f32 100644
--- a/fj-app/src/kernel/geometry/surfaces/mod.rs
+++ b/fj-kernel/src/geometry/surfaces/mod.rs
@@ -5,7 +5,7 @@ pub use self::swept::Swept;
 use fj_math::{Point, Transform, Vector};
 use nalgebra::vector;
 
-use crate::kernel::geometry;
+use crate::geometry;
 
 use super::{Curve, Line};
 
diff --git a/fj-app/src/kernel/geometry/surfaces/swept.rs b/fj-kernel/src/geometry/surfaces/swept.rs
similarity index 96%
rename from fj-app/src/kernel/geometry/surfaces/swept.rs
rename to fj-kernel/src/geometry/surfaces/swept.rs
index b8f6149fd..45027d914 100644
--- a/fj-app/src/kernel/geometry/surfaces/swept.rs
+++ b/fj-kernel/src/geometry/surfaces/swept.rs
@@ -1,6 +1,6 @@
 use fj_math::{Point, Transform, Vector};
 
-use crate::kernel::geometry::Curve;
+use crate::geometry::Curve;
 
 /// A surface that was swept from a curve
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
@@ -16,7 +16,7 @@ impl Swept {
     /// Construct a plane from 3 points
     #[cfg(test)]
     pub fn plane_from_points([a, b, c]: [Point<3>; 3]) -> Self {
-        use crate::kernel::geometry::Line;
+        use crate::geometry::Line;
 
         let curve = Curve::Line(Line::from_points([a, b]));
         let path = c - a;
@@ -57,7 +57,7 @@ mod tests {
 
     use fj_math::{Point, Vector};
 
-    use crate::kernel::geometry::{Curve, Line};
+    use crate::geometry::{Curve, Line};
 
     use super::Swept;
 
diff --git a/fj-app/src/kernel/mod.rs b/fj-kernel/src/lib.rs
similarity index 100%
rename from fj-app/src/kernel/mod.rs
rename to fj-kernel/src/lib.rs
diff --git a/fj-app/src/kernel/shape/geometry.rs b/fj-kernel/src/shape/geometry.rs
similarity index 99%
rename from fj-app/src/kernel/shape/geometry.rs
rename to fj-kernel/src/shape/geometry.rs
index 873ce7d13..e13554172 100644
--- a/fj-app/src/kernel/shape/geometry.rs
+++ b/fj-kernel/src/shape/geometry.rs
@@ -1,6 +1,6 @@
 use fj_math::{Point, Transform};
 
-use crate::kernel::{
+use crate::{
     geometry::{Curve, Surface},
     topology::faces::Face,
 };
diff --git a/fj-app/src/kernel/shape/handle.rs b/fj-kernel/src/shape/handle.rs
similarity index 100%
rename from fj-app/src/kernel/shape/handle.rs
rename to fj-kernel/src/shape/handle.rs
diff --git a/fj-app/src/kernel/shape/iter.rs b/fj-kernel/src/shape/iter.rs
similarity index 100%
rename from fj-app/src/kernel/shape/iter.rs
rename to fj-kernel/src/shape/iter.rs
diff --git a/fj-app/src/kernel/shape/mod.rs b/fj-kernel/src/shape/mod.rs
similarity index 100%
rename from fj-app/src/kernel/shape/mod.rs
rename to fj-kernel/src/shape/mod.rs
diff --git a/fj-app/src/kernel/shape/topology.rs b/fj-kernel/src/shape/topology.rs
similarity index 99%
rename from fj-app/src/kernel/shape/topology.rs
rename to fj-kernel/src/shape/topology.rs
index 56bef7f09..32d1a76e4 100644
--- a/fj-app/src/kernel/shape/topology.rs
+++ b/fj-kernel/src/shape/topology.rs
@@ -3,7 +3,7 @@ use std::collections::HashSet;
 use fj_debug::DebugInfo;
 use fj_math::{Point, Scalar, Triangle, Vector};
 
-use crate::kernel::{
+use crate::{
     geometry::{Circle, Curve, Line},
     topology::{
         edges::{Cycle, Edge},
@@ -261,7 +261,7 @@ mod tests {
 
     use fj_math::{Point, Scalar};
 
-    use crate::kernel::{
+    use crate::{
         geometry::{Curve, Line, Surface},
         shape::{handle::Handle, Shape, ValidationError},
         topology::{
diff --git a/fj-app/src/kernel/shape/validate.rs b/fj-kernel/src/shape/validate.rs
similarity index 99%
rename from fj-app/src/kernel/shape/validate.rs
rename to fj-kernel/src/shape/validate.rs
index c1497178c..4c3c8b283 100644
--- a/fj-app/src/kernel/shape/validate.rs
+++ b/fj-kernel/src/shape/validate.rs
@@ -1,6 +1,6 @@
 use std::collections::HashSet;
 
-use crate::kernel::{
+use crate::{
     geometry::{Curve, Surface},
     topology::{
         edges::{Cycle, Edge},
diff --git a/fj-app/src/kernel/topology/edges.rs b/fj-kernel/src/topology/edges.rs
similarity index 98%
rename from fj-app/src/kernel/topology/edges.rs
rename to fj-kernel/src/topology/edges.rs
index c2e3cd340..ebcfad3fd 100644
--- a/fj-app/src/kernel/topology/edges.rs
+++ b/fj-kernel/src/topology/edges.rs
@@ -1,6 +1,6 @@
 use std::hash::{Hash, Hasher};
 
-use crate::kernel::{geometry::Curve, shape::Handle};
+use crate::{geometry::Curve, shape::Handle};
 
 use super::vertices::Vertex;
 
diff --git a/fj-app/src/kernel/topology/faces.rs b/fj-kernel/src/topology/faces.rs
similarity index 99%
rename from fj-app/src/kernel/topology/faces.rs
rename to fj-kernel/src/topology/faces.rs
index a5b805d88..bbb363809 100644
--- a/fj-app/src/kernel/topology/faces.rs
+++ b/fj-kernel/src/topology/faces.rs
@@ -8,7 +8,7 @@ use fj_math::{Aabb, Scalar, Segment, Triangle};
 use parry2d_f64::query::{Ray as Ray2, RayCast as _};
 use parry3d_f64::query::Ray as Ray3;
 
-use crate::kernel::{
+use crate::{
     algorithms::{approximation::Approximation, triangulation::triangulate},
     geometry::Surface,
     shape::Handle,
diff --git a/fj-app/src/kernel/topology/mod.rs b/fj-kernel/src/topology/mod.rs
similarity index 100%
rename from fj-app/src/kernel/topology/mod.rs
rename to fj-kernel/src/topology/mod.rs
diff --git a/fj-app/src/kernel/topology/vertices.rs b/fj-kernel/src/topology/vertices.rs
similarity index 97%
rename from fj-app/src/kernel/topology/vertices.rs
rename to fj-kernel/src/topology/vertices.rs
index 76c85f38f..5e54439ea 100644
--- a/fj-app/src/kernel/topology/vertices.rs
+++ b/fj-kernel/src/topology/vertices.rs
@@ -2,7 +2,7 @@ use std::hash::Hash;
 
 use fj_math::Point;
 
-use crate::kernel::shape::Handle;
+use crate::shape::Handle;
 
 /// A vertex
 ///

From 7f051a855e4dddf8c95a5f8cbfc4fffbd0b21287 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:04:23 +0100
Subject: [PATCH 04/16] Fix Clippy warning

This is another one of those that only showed up, as I extracted code
into a separate crate.
---
 fj-kernel/src/shape/mod.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fj-kernel/src/shape/mod.rs b/fj-kernel/src/shape/mod.rs
index 71965f066..d50a1d685 100644
--- a/fj-kernel/src/shape/mod.rs
+++ b/fj-kernel/src/shape/mod.rs
@@ -109,6 +109,12 @@ impl Shape {
     }
 }
 
+impl Default for Shape {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 type Points = Store<Point<3>>;
 type Curves = Store<Curve>;
 type Surfaces = Store<Surface>;

From a5d4ddedb313fa051c228819999e82b8eecb03c7 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:08:50 +0100
Subject: [PATCH 05/16] Add re-exports to `algorithms`

---
 fj-app/src/operations/sweep.rs  | 2 +-
 fj-kernel/src/algorithms/mod.rs | 5 +++++
 fj-kernel/src/topology/faces.rs | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fj-app/src/operations/sweep.rs b/fj-app/src/operations/sweep.rs
index cf8099c92..15f816fc8 100644
--- a/fj-app/src/operations/sweep.rs
+++ b/fj-app/src/operations/sweep.rs
@@ -1,5 +1,5 @@
 use fj_debug::DebugInfo;
-use fj_kernel::{algorithms::sweep::sweep_shape, shape::Shape};
+use fj_kernel::{algorithms::sweep_shape, shape::Shape};
 use fj_math::{Aabb, Scalar, Vector};
 
 use super::ToShape;
diff --git a/fj-kernel/src/algorithms/mod.rs b/fj-kernel/src/algorithms/mod.rs
index 77c393267..0ff398c24 100644
--- a/fj-kernel/src/algorithms/mod.rs
+++ b/fj-kernel/src/algorithms/mod.rs
@@ -1,3 +1,8 @@
 pub mod approximation;
 pub mod sweep;
 pub mod triangulation;
+
+pub use self::{
+    approximation::Approximation, sweep::sweep_shape,
+    triangulation::triangulate,
+};
diff --git a/fj-kernel/src/topology/faces.rs b/fj-kernel/src/topology/faces.rs
index bbb363809..87337ef0a 100644
--- a/fj-kernel/src/topology/faces.rs
+++ b/fj-kernel/src/topology/faces.rs
@@ -9,7 +9,7 @@ use parry2d_f64::query::{Ray as Ray2, RayCast as _};
 use parry3d_f64::query::Ray as Ray3;
 
 use crate::{
-    algorithms::{approximation::Approximation, triangulation::triangulate},
+    algorithms::{triangulate, Approximation},
     geometry::Surface,
     shape::Handle,
 };

From 0cebb309db347ccd8acfcafbf46aca64f871694a Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:09:20 +0100
Subject: [PATCH 06/16] Make modules in `algorihms` private

This simplifies the public API.
---
 fj-kernel/src/algorithms/mod.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fj-kernel/src/algorithms/mod.rs b/fj-kernel/src/algorithms/mod.rs
index 0ff398c24..cdbbd0604 100644
--- a/fj-kernel/src/algorithms/mod.rs
+++ b/fj-kernel/src/algorithms/mod.rs
@@ -1,6 +1,6 @@
-pub mod approximation;
-pub mod sweep;
-pub mod triangulation;
+mod approximation;
+mod sweep;
+mod triangulation;
 
 pub use self::{
     approximation::Approximation, sweep::sweep_shape,

From c7b3efff8e063cd075821744e2dfa48b3ef58627 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:16:28 +0100
Subject: [PATCH 07/16] Rename `Swept` to `SweptCurve`

This makes the name a bit less compact, but more clear.
---
 fj-kernel/src/algorithms/sweep.rs        |  8 ++++----
 fj-kernel/src/geometry/surfaces/mod.rs   |  6 +++---
 fj-kernel/src/geometry/surfaces/swept.rs | 14 +++++++-------
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/fj-kernel/src/algorithms/sweep.rs b/fj-kernel/src/algorithms/sweep.rs
index b1723811e..3c7269d2f 100644
--- a/fj-kernel/src/algorithms/sweep.rs
+++ b/fj-kernel/src/algorithms/sweep.rs
@@ -3,7 +3,7 @@ use std::collections::HashMap;
 use fj_math::{Scalar, Transform, Triangle, Vector};
 
 use crate::{
-    geometry::{surfaces::Swept, Surface},
+    geometry::{surfaces::SweptCurve, Surface},
     shape::{Handle, Shape},
     topology::{
         edges::{Cycle, Edge},
@@ -237,7 +237,7 @@ pub fn sweep_shape(
                     source_to_top.edges.get(edge_source).unwrap().clone();
 
                 let surface =
-                    target.geometry().add_surface(Surface::Swept(Swept {
+                    target.geometry().add_surface(Surface::Swept(SweptCurve {
                         curve: bottom_edge.get().curve(),
                         path,
                     }));
@@ -324,7 +324,7 @@ mod tests {
     use fj_math::{Point, Scalar, Vector};
 
     use crate::{
-        geometry::{surfaces::Swept, Surface},
+        geometry::{surfaces::SweptCurve, Surface},
         shape::{Handle, Shape},
         topology::{edges::Cycle, faces::Face, vertices::Vertex},
     };
@@ -408,7 +408,7 @@ mod tests {
                 .unwrap();
 
             let surface = shape.geometry().add_surface(Surface::Swept(
-                Swept::plane_from_points(
+                SweptCurve::plane_from_points(
                     [a, b, c].map(|vertex| vertex.get().point()),
                 ),
             ));
diff --git a/fj-kernel/src/geometry/surfaces/mod.rs b/fj-kernel/src/geometry/surfaces/mod.rs
index adbdb2f32..1db485583 100644
--- a/fj-kernel/src/geometry/surfaces/mod.rs
+++ b/fj-kernel/src/geometry/surfaces/mod.rs
@@ -1,6 +1,6 @@
 pub mod swept;
 
-pub use self::swept::Swept;
+pub use self::swept::SweptCurve;
 
 use fj_math::{Point, Transform, Vector};
 use nalgebra::vector;
@@ -13,13 +13,13 @@ use super::{Curve, Line};
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub enum Surface {
     /// A swept curve
-    Swept(Swept),
+    Swept(SweptCurve),
 }
 
 impl Surface {
     /// Construct a `Surface` that represents the x-y plane
     pub fn x_y_plane() -> Self {
-        Self::Swept(Swept {
+        Self::Swept(SweptCurve {
             curve: Curve::Line(Line {
                 origin: Point::origin(),
                 direction: vector![1., 0., 0.].into(),
diff --git a/fj-kernel/src/geometry/surfaces/swept.rs b/fj-kernel/src/geometry/surfaces/swept.rs
index 45027d914..3c6f6531e 100644
--- a/fj-kernel/src/geometry/surfaces/swept.rs
+++ b/fj-kernel/src/geometry/surfaces/swept.rs
@@ -4,7 +4,7 @@ use crate::geometry::Curve;
 
 /// A surface that was swept from a curve
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
-pub struct Swept {
+pub struct SweptCurve {
     /// The curve that this surface was swept from
     pub curve: Curve,
 
@@ -12,7 +12,7 @@ pub struct Swept {
     pub path: Vector<3>,
 }
 
-impl Swept {
+impl SweptCurve {
     /// Construct a plane from 3 points
     #[cfg(test)]
     pub fn plane_from_points([a, b, c]: [Point<3>; 3]) -> Self {
@@ -59,11 +59,11 @@ mod tests {
 
     use crate::geometry::{Curve, Line};
 
-    use super::Swept;
+    use super::SweptCurve;
 
     #[test]
     fn point_model_to_surface() {
-        let swept = Swept {
+        let swept = SweptCurve {
             curve: Curve::Line(Line {
                 origin: Point::from([1., 0., 0.]),
                 direction: Vector::from([0., 2., 0.]),
@@ -76,7 +76,7 @@ mod tests {
         verify(&swept, Point::from([1., 1.]));
         verify(&swept, Point::from([2., 3.]));
 
-        fn verify(swept: &Swept, surface_point: Point<2>) {
+        fn verify(swept: &SweptCurve, surface_point: Point<2>) {
             let point = swept.point_surface_to_model(&surface_point);
             let result = swept.point_model_to_surface(&point);
 
@@ -86,7 +86,7 @@ mod tests {
 
     #[test]
     fn point_surface_to_model() {
-        let swept = Swept {
+        let swept = SweptCurve {
             curve: Curve::Line(Line {
                 origin: Point::from([1., 0., 0.]),
                 direction: Vector::from([0., 2., 0.]),
@@ -102,7 +102,7 @@ mod tests {
 
     #[test]
     fn vector_surface_to_model() {
-        let swept = Swept {
+        let swept = SweptCurve {
             curve: Curve::Line(Line {
                 origin: Point::from([1., 0., 0.]),
                 direction: Vector::from([0., 2., 0.]),

From 4fee84d653fc5c747681e3d866075b3dc6e1669c Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:17:42 +0100
Subject: [PATCH 08/16] Update name of enum variant

---
 fj-kernel/src/algorithms/sweep.rs      |  9 +++++----
 fj-kernel/src/geometry/surfaces/mod.rs | 18 ++++++++++++------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/fj-kernel/src/algorithms/sweep.rs b/fj-kernel/src/algorithms/sweep.rs
index 3c7269d2f..12b62c862 100644
--- a/fj-kernel/src/algorithms/sweep.rs
+++ b/fj-kernel/src/algorithms/sweep.rs
@@ -236,11 +236,12 @@ pub fn sweep_shape(
                 let top_edge =
                     source_to_top.edges.get(edge_source).unwrap().clone();
 
-                let surface =
-                    target.geometry().add_surface(Surface::Swept(SweptCurve {
+                let surface = target.geometry().add_surface(
+                    Surface::SweptCurve(SweptCurve {
                         curve: bottom_edge.get().curve(),
                         path,
-                    }));
+                    }),
+                );
 
                 let cycle = target
                     .topology()
@@ -407,7 +408,7 @@ mod tests {
                 })
                 .unwrap();
 
-            let surface = shape.geometry().add_surface(Surface::Swept(
+            let surface = shape.geometry().add_surface(Surface::SweptCurve(
                 SweptCurve::plane_from_points(
                     [a, b, c].map(|vertex| vertex.get().point()),
                 ),
diff --git a/fj-kernel/src/geometry/surfaces/mod.rs b/fj-kernel/src/geometry/surfaces/mod.rs
index 1db485583..4fc73864c 100644
--- a/fj-kernel/src/geometry/surfaces/mod.rs
+++ b/fj-kernel/src/geometry/surfaces/mod.rs
@@ -13,13 +13,13 @@ use super::{Curve, Line};
 #[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub enum Surface {
     /// A swept curve
-    Swept(SweptCurve),
+    SweptCurve(SweptCurve),
 }
 
 impl Surface {
     /// Construct a `Surface` that represents the x-y plane
     pub fn x_y_plane() -> Self {
-        Self::Swept(SweptCurve {
+        Self::SweptCurve(SweptCurve {
             curve: Curve::Line(Line {
                 origin: Point::origin(),
                 direction: vector![1., 0., 0.].into(),
@@ -32,7 +32,9 @@ impl Surface {
     #[must_use]
     pub fn transform(self, transform: &Transform) -> Self {
         match self {
-            Self::Swept(surface) => Self::Swept(surface.transform(transform)),
+            Self::SweptCurve(surface) => {
+                Self::SweptCurve(surface.transform(transform))
+            }
         }
     }
 
@@ -42,7 +44,9 @@ impl Surface {
         point_3d: Point<3>,
     ) -> geometry::Point<2> {
         let point_2d = match self {
-            Self::Swept(surface) => surface.point_model_to_surface(&point_3d),
+            Self::SweptCurve(surface) => {
+                surface.point_model_to_surface(&point_3d)
+            }
         };
 
         geometry::Point::new(point_2d, point_3d)
@@ -51,14 +55,16 @@ impl Surface {
     /// Convert a point in surface coordinates to model coordinates
     pub fn point_surface_to_model(&self, point: &Point<2>) -> Point<3> {
         match self {
-            Self::Swept(surface) => surface.point_surface_to_model(point),
+            Self::SweptCurve(surface) => surface.point_surface_to_model(point),
         }
     }
 
     /// Convert a vector in surface coordinates to model coordinates
     pub fn vector_surface_to_model(&self, vector: &Vector<2>) -> Vector<3> {
         match self {
-            Self::Swept(surface) => surface.vector_surface_to_model(vector),
+            Self::SweptCurve(surface) => {
+                surface.vector_surface_to_model(vector)
+            }
         }
     }
 }

From 5f56748880cb27e5b6f6b8f405b4d4557faf5f2c Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:18:50 +0100
Subject: [PATCH 09/16] Update order of code

Public re-exports of `self` types are closely related to the module
declarations, while the other `use` statements are related to the
implementation below them. I like to emphasize this via their proximity.
---
 fj-kernel/src/geometry/curves/mod.rs | 4 ++--
 fj-kernel/src/shape/mod.rs           | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fj-kernel/src/geometry/curves/mod.rs b/fj-kernel/src/geometry/curves/mod.rs
index c422ee1a0..343062679 100644
--- a/fj-kernel/src/geometry/curves/mod.rs
+++ b/fj-kernel/src/geometry/curves/mod.rs
@@ -1,10 +1,10 @@
 mod circle;
 mod line;
 
-use fj_math::{Point, Scalar, Transform, Vector};
-
 pub use self::{circle::Circle, line::Line};
 
+use fj_math::{Point, Scalar, Transform, Vector};
+
 /// A one-dimensional shape
 ///
 /// The word "curve" is used as an umbrella term for all one-dimensional shapes,
diff --git a/fj-kernel/src/shape/mod.rs b/fj-kernel/src/shape/mod.rs
index d50a1d685..7e6191e4b 100644
--- a/fj-kernel/src/shape/mod.rs
+++ b/fj-kernel/src/shape/mod.rs
@@ -4,8 +4,6 @@ pub mod iter;
 pub mod topology;
 pub mod validate;
 
-use fj_math::{Point, Scalar};
-
 pub use self::{
     geometry::Geometry,
     handle::Handle,
@@ -14,6 +12,8 @@ pub use self::{
     validate::{ValidationError, ValidationResult},
 };
 
+use fj_math::{Point, Scalar};
+
 use super::{
     geometry::{Curve, Surface},
     topology::{

From 8588aee08588b7815767ea09e42f49494ba0b3b8 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:23:47 +0100
Subject: [PATCH 10/16] Add missing re-export

---
 fj-kernel/src/algorithms/sweep.rs | 4 ++--
 fj-kernel/src/geometry/mod.rs     | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fj-kernel/src/algorithms/sweep.rs b/fj-kernel/src/algorithms/sweep.rs
index 12b62c862..6f33acadf 100644
--- a/fj-kernel/src/algorithms/sweep.rs
+++ b/fj-kernel/src/algorithms/sweep.rs
@@ -3,7 +3,7 @@ use std::collections::HashMap;
 use fj_math::{Scalar, Transform, Triangle, Vector};
 
 use crate::{
-    geometry::{surfaces::SweptCurve, Surface},
+    geometry::{Surface, SweptCurve},
     shape::{Handle, Shape},
     topology::{
         edges::{Cycle, Edge},
@@ -325,7 +325,7 @@ mod tests {
     use fj_math::{Point, Scalar, Vector};
 
     use crate::{
-        geometry::{surfaces::SweptCurve, Surface},
+        geometry::{Surface, SweptCurve},
         shape::{Handle, Shape},
         topology::{edges::Cycle, faces::Face, vertices::Vertex},
     };
diff --git a/fj-kernel/src/geometry/mod.rs b/fj-kernel/src/geometry/mod.rs
index 7b9e5fdf3..8c475a9c0 100644
--- a/fj-kernel/src/geometry/mod.rs
+++ b/fj-kernel/src/geometry/mod.rs
@@ -5,5 +5,5 @@ pub mod surfaces;
 pub use self::{
     curves::{Circle, Curve, Line},
     points::Point,
-    surfaces::Surface,
+    surfaces::{Surface, SweptCurve},
 };

From d8ced4f3c33557cf2f2c818deaddcc41db2359e8 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:24:39 +0100
Subject: [PATCH 11/16] Simplify public API of `geometry` module

---
 fj-kernel/src/geometry/mod.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fj-kernel/src/geometry/mod.rs b/fj-kernel/src/geometry/mod.rs
index 8c475a9c0..59d2782ee 100644
--- a/fj-kernel/src/geometry/mod.rs
+++ b/fj-kernel/src/geometry/mod.rs
@@ -1,6 +1,6 @@
-pub mod curves;
-pub mod points;
-pub mod surfaces;
+mod curves;
+mod points;
+mod surfaces;
 
 pub use self::{
     curves::{Circle, Curve, Line},

From 815dd933711d261c980e0026365d58358f9e86e6 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:28:17 +0100
Subject: [PATCH 12/16] Simplify public API of `shape` module

---
 fj-kernel/src/shape/mod.rs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fj-kernel/src/shape/mod.rs b/fj-kernel/src/shape/mod.rs
index 7e6191e4b..3238da950 100644
--- a/fj-kernel/src/shape/mod.rs
+++ b/fj-kernel/src/shape/mod.rs
@@ -1,8 +1,8 @@
-pub mod geometry;
-pub mod handle;
-pub mod iter;
-pub mod topology;
-pub mod validate;
+mod geometry;
+mod handle;
+mod iter;
+mod topology;
+mod validate;
 
 pub use self::{
     geometry::Geometry,

From 4cd98f20d78716aa103fbbafdc04ab4427a8d4ce Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:37:31 +0100
Subject: [PATCH 13/16] Add re-exports to `topology` module

---
 fj-app/src/operations/circle.rs           |  2 +-
 fj-app/src/operations/difference_2d.rs    |  6 +-----
 fj-app/src/operations/group.rs            |  6 +-----
 fj-app/src/operations/sketch.rs           |  2 +-
 fj-kernel/src/algorithms/approximation.rs |  8 ++------
 fj-kernel/src/algorithms/sweep.rs         |  8 ++------
 fj-kernel/src/shape/geometry.rs           |  2 +-
 fj-kernel/src/shape/mod.rs                |  6 +-----
 fj-kernel/src/shape/topology.rs           | 12 ++----------
 fj-kernel/src/shape/validate.rs           |  6 +-----
 fj-kernel/src/topology/mod.rs             |  6 ++++++
 11 files changed, 19 insertions(+), 45 deletions(-)

diff --git a/fj-app/src/operations/circle.rs b/fj-app/src/operations/circle.rs
index c495e6a87..0bb8880c0 100644
--- a/fj-app/src/operations/circle.rs
+++ b/fj-app/src/operations/circle.rs
@@ -2,7 +2,7 @@ use fj_debug::DebugInfo;
 use fj_kernel::{
     geometry::Surface,
     shape::Shape,
-    topology::{edges::Cycle, faces::Face},
+    topology::{Cycle, Face},
 };
 use fj_math::{Aabb, Point, Scalar};
 
diff --git a/fj-app/src/operations/difference_2d.rs b/fj-app/src/operations/difference_2d.rs
index 265804849..9abe08efd 100644
--- a/fj-app/src/operations/difference_2d.rs
+++ b/fj-app/src/operations/difference_2d.rs
@@ -3,11 +3,7 @@ use std::collections::HashMap;
 use fj_debug::DebugInfo;
 use fj_kernel::{
     shape::Shape,
-    topology::{
-        edges::{Cycle, Edge},
-        faces::Face,
-        vertices::Vertex,
-    },
+    topology::{Cycle, Edge, Face, Vertex},
 };
 use fj_math::{Aabb, Scalar};
 
diff --git a/fj-app/src/operations/group.rs b/fj-app/src/operations/group.rs
index 2d40de3e2..94b4de971 100644
--- a/fj-app/src/operations/group.rs
+++ b/fj-app/src/operations/group.rs
@@ -3,11 +3,7 @@ use std::collections::HashMap;
 use fj_debug::DebugInfo;
 use fj_kernel::{
     shape::Shape,
-    topology::{
-        edges::{Cycle, Edge},
-        faces::Face,
-        vertices::Vertex,
-    },
+    topology::{Cycle, Edge, Face, Vertex},
 };
 use fj_math::{Aabb, Scalar};
 
diff --git a/fj-app/src/operations/sketch.rs b/fj-app/src/operations/sketch.rs
index bcd4b9baf..cc48fc3c1 100644
--- a/fj-app/src/operations/sketch.rs
+++ b/fj-app/src/operations/sketch.rs
@@ -2,7 +2,7 @@ use fj_debug::DebugInfo;
 use fj_kernel::{
     geometry::Surface,
     shape::Shape,
-    topology::{edges::Cycle, faces::Face, vertices::Vertex},
+    topology::{Cycle, Face, Vertex},
 };
 use fj_math::{Aabb, Point, Scalar};
 
diff --git a/fj-kernel/src/algorithms/approximation.rs b/fj-kernel/src/algorithms/approximation.rs
index 138540cdf..161e27187 100644
--- a/fj-kernel/src/algorithms/approximation.rs
+++ b/fj-kernel/src/algorithms/approximation.rs
@@ -2,11 +2,7 @@ use std::collections::HashSet;
 
 use fj_math::{Point, Scalar, Segment};
 
-use crate::topology::{
-    edges::{Cycle, Edge},
-    faces::Face,
-    vertices::Vertex,
-};
+use crate::topology::{Cycle, Edge, Face, Vertex};
 
 /// An approximation of an edge, multiple edges, or a face
 #[derive(Debug, PartialEq)]
@@ -137,7 +133,7 @@ mod tests {
     use crate::{
         geometry::Surface,
         shape::Shape,
-        topology::{edges::Cycle, faces::Face, vertices::Vertex},
+        topology::{Cycle, Face, Vertex},
     };
 
     use super::{approximate_edge, Approximation};
diff --git a/fj-kernel/src/algorithms/sweep.rs b/fj-kernel/src/algorithms/sweep.rs
index 6f33acadf..1b2bd3542 100644
--- a/fj-kernel/src/algorithms/sweep.rs
+++ b/fj-kernel/src/algorithms/sweep.rs
@@ -5,11 +5,7 @@ use fj_math::{Scalar, Transform, Triangle, Vector};
 use crate::{
     geometry::{Surface, SweptCurve},
     shape::{Handle, Shape},
-    topology::{
-        edges::{Cycle, Edge},
-        faces::Face,
-        vertices::Vertex,
-    },
+    topology::{Cycle, Edge, Face, Vertex},
 };
 
 use super::approximation::Approximation;
@@ -327,7 +323,7 @@ mod tests {
     use crate::{
         geometry::{Surface, SweptCurve},
         shape::{Handle, Shape},
-        topology::{edges::Cycle, faces::Face, vertices::Vertex},
+        topology::{Cycle, Face, Vertex},
     };
 
     use super::sweep_shape;
diff --git a/fj-kernel/src/shape/geometry.rs b/fj-kernel/src/shape/geometry.rs
index e13554172..75af93c4e 100644
--- a/fj-kernel/src/shape/geometry.rs
+++ b/fj-kernel/src/shape/geometry.rs
@@ -2,7 +2,7 @@ use fj_math::{Point, Transform};
 
 use crate::{
     geometry::{Curve, Surface},
-    topology::faces::Face,
+    topology::Face,
 };
 
 use super::{
diff --git a/fj-kernel/src/shape/mod.rs b/fj-kernel/src/shape/mod.rs
index 3238da950..683f01f20 100644
--- a/fj-kernel/src/shape/mod.rs
+++ b/fj-kernel/src/shape/mod.rs
@@ -16,11 +16,7 @@ use fj_math::{Point, Scalar};
 
 use super::{
     geometry::{Curve, Surface},
-    topology::{
-        edges::{Cycle, Edge},
-        faces::Face,
-        vertices::Vertex,
-    },
+    topology::{Cycle, Edge, Face, Vertex},
 };
 
 use self::handle::Storage;
diff --git a/fj-kernel/src/shape/topology.rs b/fj-kernel/src/shape/topology.rs
index 32d1a76e4..ed8199e18 100644
--- a/fj-kernel/src/shape/topology.rs
+++ b/fj-kernel/src/shape/topology.rs
@@ -5,11 +5,7 @@ use fj_math::{Point, Scalar, Triangle, Vector};
 
 use crate::{
     geometry::{Circle, Curve, Line},
-    topology::{
-        edges::{Cycle, Edge},
-        faces::Face,
-        vertices::Vertex,
-    },
+    topology::{Cycle, Edge, Face, Vertex},
 };
 
 use super::{
@@ -264,11 +260,7 @@ mod tests {
     use crate::{
         geometry::{Curve, Line, Surface},
         shape::{handle::Handle, Shape, ValidationError},
-        topology::{
-            edges::{Cycle, Edge},
-            faces::Face,
-            vertices::Vertex,
-        },
+        topology::{Cycle, Edge, Face, Vertex},
     };
 
     const MIN_DISTANCE: f64 = 5e-7;
diff --git a/fj-kernel/src/shape/validate.rs b/fj-kernel/src/shape/validate.rs
index 4c3c8b283..167e37089 100644
--- a/fj-kernel/src/shape/validate.rs
+++ b/fj-kernel/src/shape/validate.rs
@@ -2,11 +2,7 @@ use std::collections::HashSet;
 
 use crate::{
     geometry::{Curve, Surface},
-    topology::{
-        edges::{Cycle, Edge},
-        faces::Face,
-        vertices::Vertex,
-    },
+    topology::{Cycle, Edge, Face, Vertex},
 };
 
 use super::Handle;
diff --git a/fj-kernel/src/topology/mod.rs b/fj-kernel/src/topology/mod.rs
index 8be51df18..4b12a9469 100644
--- a/fj-kernel/src/topology/mod.rs
+++ b/fj-kernel/src/topology/mod.rs
@@ -14,3 +14,9 @@
 pub mod edges;
 pub mod faces;
 pub mod vertices;
+
+pub use self::{
+    edges::{Cycle, Edge},
+    faces::Face,
+    vertices::Vertex,
+};

From b6bc41a5019aa220b4e3d4e09859b627c71fe172 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:37:47 +0100
Subject: [PATCH 14/16] Simplify public API of `topology` module

---
 fj-kernel/src/topology/mod.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fj-kernel/src/topology/mod.rs b/fj-kernel/src/topology/mod.rs
index 4b12a9469..e6f8544f1 100644
--- a/fj-kernel/src/topology/mod.rs
+++ b/fj-kernel/src/topology/mod.rs
@@ -11,9 +11,9 @@
 //! definition of identity. Two [`Handle`]s are only considered equal, if they
 //! refer to objects in the same memory location.
 
-pub mod edges;
-pub mod faces;
-pub mod vertices;
+mod edges;
+mod faces;
+mod vertices;
 
 pub use self::{
     edges::{Cycle, Edge},

From db4a3f829cab0dd3b8eb810929faa57f1fe8fa80 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:41:07 +0100
Subject: [PATCH 15/16] Update documentation of `fj-kernel`

---
 fj-kernel/src/algorithms/mod.rs         | 5 +++++
 fj-kernel/src/geometry/curves/circle.rs | 5 +++++
 fj-kernel/src/geometry/curves/line.rs   | 2 +-
 fj-kernel/src/geometry/curves/mod.rs    | 1 +
 fj-kernel/src/geometry/mod.rs           | 7 +++++++
 fj-kernel/src/shape/iter.rs             | 3 +++
 fj-kernel/src/shape/mod.rs              | 4 ++++
 fj-kernel/src/shape/topology.rs         | 1 +
 fj-kernel/src/topology/edges.rs         | 1 +
 fj-kernel/src/topology/faces.rs         | 3 +++
 fj-kernel/src/topology/mod.rs           | 5 +++++
 fj-kernel/src/topology/vertices.rs      | 1 +
 12 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/fj-kernel/src/algorithms/mod.rs b/fj-kernel/src/algorithms/mod.rs
index cdbbd0604..14e0f3d1d 100644
--- a/fj-kernel/src/algorithms/mod.rs
+++ b/fj-kernel/src/algorithms/mod.rs
@@ -1,3 +1,8 @@
+//! Collection of algorithms that are used by the kernel
+//!
+//! Algorithmic code is collected in this module, to keep other modules focused
+//! on their respective purpose.
+
 mod approximation;
 mod sweep;
 mod triangulation;
diff --git a/fj-kernel/src/geometry/curves/circle.rs b/fj-kernel/src/geometry/curves/circle.rs
index 68eceeedb..e2596e091 100644
--- a/fj-kernel/src/geometry/curves/circle.rs
+++ b/fj-kernel/src/geometry/curves/circle.rs
@@ -22,6 +22,7 @@ impl Circle {
         self.center
     }
 
+    /// Create a new instance that is transformed by `transform`
     #[must_use]
     pub fn transform(self, transform: &Transform) -> Self {
         let radius = self.radius.to_xyz();
@@ -75,6 +76,10 @@ impl Circle {
         Vector::from([x, y, Scalar::ZERO])
     }
 
+    /// Approximate the circle
+    ///
+    /// `tolerance` specifies how much the approximation is allowed to deviate
+    /// from the circle.
     pub fn approx(&self, tolerance: Scalar, out: &mut Vec<Point<3>>) {
         let radius = self.radius.magnitude();
 
diff --git a/fj-kernel/src/geometry/curves/line.rs b/fj-kernel/src/geometry/curves/line.rs
index 0ceeb225d..24865ce0d 100644
--- a/fj-kernel/src/geometry/curves/line.rs
+++ b/fj-kernel/src/geometry/curves/line.rs
@@ -28,7 +28,7 @@ impl Line {
         self.origin
     }
 
-    /// Transform the line
+    /// Create a new instance that is transformed by `transform`
     #[must_use]
     pub fn transform(self, transform: &Transform) -> Self {
         Self {
diff --git a/fj-kernel/src/geometry/curves/mod.rs b/fj-kernel/src/geometry/curves/mod.rs
index 343062679..e39a18b7f 100644
--- a/fj-kernel/src/geometry/curves/mod.rs
+++ b/fj-kernel/src/geometry/curves/mod.rs
@@ -32,6 +32,7 @@ impl Curve {
         }
     }
 
+    /// Create a new instance that is transformed by `transform`
     #[must_use]
     pub fn transform(self, transform: &Transform) -> Self {
         match self {
diff --git a/fj-kernel/src/geometry/mod.rs b/fj-kernel/src/geometry/mod.rs
index 59d2782ee..4781fe43d 100644
--- a/fj-kernel/src/geometry/mod.rs
+++ b/fj-kernel/src/geometry/mod.rs
@@ -1,3 +1,10 @@
+//! Geometry objects
+//!
+//! Simplifying a bit, geometry is responsible for where things are, but now how
+//! they are related. The types in this module are referred to by the types in
+//! [`crate::topology`], which are responsible for defining how objects are
+//! related.
+
 mod curves;
 mod points;
 mod surfaces;
diff --git a/fj-kernel/src/shape/iter.rs b/fj-kernel/src/shape/iter.rs
index a460f5cd5..53cd76ec4 100644
--- a/fj-kernel/src/shape/iter.rs
+++ b/fj-kernel/src/shape/iter.rs
@@ -5,6 +5,9 @@ use super::{
     Store,
 };
 
+/// An iterator over geometric or topological objects
+///
+/// Returned by various methods of the [`Shape`] API.
 pub struct Iter<'r, T> {
     inner: Inner<'r, T>,
 }
diff --git a/fj-kernel/src/shape/mod.rs b/fj-kernel/src/shape/mod.rs
index 683f01f20..18cf72a9f 100644
--- a/fj-kernel/src/shape/mod.rs
+++ b/fj-kernel/src/shape/mod.rs
@@ -1,3 +1,7 @@
+//! The API used for creating and manipulating shapes
+//!
+//! See [`Shape`], which is the main entry point to this API.
+
 mod geometry;
 mod handle;
 mod iter;
diff --git a/fj-kernel/src/shape/topology.rs b/fj-kernel/src/shape/topology.rs
index ed8199e18..46cb5cc94 100644
--- a/fj-kernel/src/shape/topology.rs
+++ b/fj-kernel/src/shape/topology.rs
@@ -239,6 +239,7 @@ impl Topology<'_> {
         Iter::new(self.geometry.faces)
     }
 
+    /// Triangulate the shape
     pub fn triangles(
         &self,
         tolerance: Scalar,
diff --git a/fj-kernel/src/topology/edges.rs b/fj-kernel/src/topology/edges.rs
index ebcfad3fd..f844cd9f9 100644
--- a/fj-kernel/src/topology/edges.rs
+++ b/fj-kernel/src/topology/edges.rs
@@ -16,6 +16,7 @@ use super::vertices::Vertex;
 /// equality of topological objects.
 #[derive(Clone, Debug, Eq, Ord, PartialOrd)]
 pub struct Cycle {
+    /// The edges that make up the cycle
     pub edges: Vec<Handle<Edge>>,
 }
 
diff --git a/fj-kernel/src/topology/faces.rs b/fj-kernel/src/topology/faces.rs
index 87337ef0a..30529231a 100644
--- a/fj-kernel/src/topology/faces.rs
+++ b/fj-kernel/src/topology/faces.rs
@@ -43,6 +43,8 @@ pub enum Face {
         /// It might be less error-prone to specify the edges in surface
         /// coordinates.
         cycles: Vec<Handle<Cycle>>,
+
+        /// The color of the face
         color: [u8; 4],
     },
 
@@ -88,6 +90,7 @@ impl Face {
         }
     }
 
+    /// Triangulate the face
     pub fn triangles(
         &self,
         tolerance: Scalar,
diff --git a/fj-kernel/src/topology/mod.rs b/fj-kernel/src/topology/mod.rs
index e6f8544f1..6a72f0fd5 100644
--- a/fj-kernel/src/topology/mod.rs
+++ b/fj-kernel/src/topology/mod.rs
@@ -1,5 +1,10 @@
 //! Topological objects
 //!
+//! Simplifying a bit, topology is responsible for defining how objects are
+//! related, as opposed to geometry, which is responsible for where things are.
+//!
+//! The types in this module use the types from [`crate::geometry`].
+//!
 //! # Equality
 //!
 //! Equality of topological objects is defined in terms of the geometry they
diff --git a/fj-kernel/src/topology/vertices.rs b/fj-kernel/src/topology/vertices.rs
index 5e54439ea..638e95477 100644
--- a/fj-kernel/src/topology/vertices.rs
+++ b/fj-kernel/src/topology/vertices.rs
@@ -19,6 +19,7 @@ use crate::shape::Handle;
 /// equality of topological objects.
 #[derive(Clone, Debug, Eq, Ord, PartialOrd)]
 pub struct Vertex {
+    /// The point that defines the location of the vertex
     pub point: Handle<Point<3>>,
 }
 

From b529f33b3b379d6ab22df1498e06e9a47a7177e2 Mon Sep 17 00:00:00 2001
From: Hanno Braun <hanno@braun-odw.eu>
Date: Thu, 17 Mar 2022 17:41:18 +0100
Subject: [PATCH 16/16] Deny missing documentation in `fj-kernel`

---
 fj-kernel/src/lib.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fj-kernel/src/lib.rs b/fj-kernel/src/lib.rs
index 9a647f743..7e432c703 100644
--- a/fj-kernel/src/lib.rs
+++ b/fj-kernel/src/lib.rs
@@ -76,6 +76,8 @@
 //! on a per-shape basis. Forcing the user to deal with these issues up-front
 //! should lead to less work overall.
 
+#![deny(missing_docs)]
+
 pub mod algorithms;
 pub mod geometry;
 pub mod shape;