Zotac ZBOX Mount (#169)

* Add a subtract function for faces

* Add an example file for a zotac zbox PC mount

crates/opencascade/src/primitives/face.rs

@@ -91,7 +91,7 @@ impl Face {
         let profile_base = &self.inner;
         let sketch_base = ffi::TopoDS_Face_ctor();
         let angle = 0.0;
-        let fuse = 1; // 0 = subtractive, 1 = additive
+        let fuse = 0; // 0 = subtractive, 1 = additive
         let modify = false;
 
         let mut make_prism = ffi::BRepFeat_MakeDPrism_ctor(
@@ -310,6 +310,19 @@ impl Face {
         CompoundFace::from_compound(compound)
     }
 
+    pub fn subtract(&self, other: &Face) -> CompoundFace {
+        let inner_shape = ffi::cast_face_to_shape(&self.inner);
+        let other_inner_shape = ffi::cast_face_to_shape(&other.inner);
+
+        let mut fuse_operation = ffi::BRepAlgoAPI_Cut_ctor(inner_shape, other_inner_shape);
+
+        let cut_shape = fuse_operation.pin_mut().Shape();
+
+        let compound = ffi::TopoDS_cast_to_compound(cut_shape);
+
+        CompoundFace::from_compound(compound)
+    }
+
     pub fn surface_area(&self) -> f64 {
         let mut props = ffi::GProp_GProps_ctor();
 

examples/src/lib.rs

@@ -19,6 +19,7 @@ pub mod swept_wire;
 pub mod swept_wire_variable;
 pub mod turners_cube;
 pub mod variable_fillet;
+pub mod zbox_case;
 
 #[derive(Debug, Copy, Clone, PartialEq, ValueEnum)]
 pub enum Example {
@@ -40,6 +41,7 @@ pub enum Example {
     SweptWireVariable,
     TurnersCube,
     VariableFillet,
+    ZboxCase,
 }
 
 impl Example {
@@ -63,6 +65,7 @@ impl Example {
             Example::SweptWireVariable => swept_wire_variable::shape(),
             Example::TurnersCube => turners_cube::shape(),
             Example::VariableFillet => variable_fillet::shape(),
+            Example::ZboxCase => zbox_case::shape(),
         }
     }
 }

examples/src/zbox_case.rs

@@ -0,0 +1,91 @@
+use glam::dvec3;
+use opencascade::{
+    primitives::{Direction, Shape},
+    workplane::Workplane,
+};
+
+pub fn shape() -> Shape {
+    // The origin of the coordinate system is the closest bottom left corner of
+    // the PC box, when viewing its ports from behind.
+    let case_thickness = 2.0;
+    let case_width = 212.0;
+    let case_height = 60.0;
+    let case_depth = 64.0; // Not measured, arbitrary value
+
+    let hook_thickness = 3.0;
+    let wire_gap = 2.6;
+
+    let case_box = Shape::box_with_dimensions(case_width, case_height, case_depth);
+
+    let back_face = case_box.faces().farthest(Direction::PosY);
+
+    let case_box = case_box.hollow(case_thickness, [back_face]);
+
+    let port_cutout = Workplane::xz()
+        .sketch()
+        .move_to(10.0, 9.0)
+        .line_to(10.0, 55.0)
+        .line_to(200.0, 55.0)
+        .line_to(200.0, 9.0)
+        .close()
+        .to_face();
+
+    let cutout = port_cutout.extrude(dvec3(0.0, -case_thickness, 0.0)).into();
+
+    let mut case_box = case_box.subtract(&cutout);
+
+    // Add the back hooks
+    let bottom_face = case_box.faces().farthest(Direction::NegZ);
+
+    for x_offset in [-75.0, -25.0, 25.0, 75.0] {
+        let mut hook: Shape = bottom_face
+            .workplane()
+            .translated(dvec3(x_offset, -20.0, 0.0))
+            .rect(40.0, 20.0)
+            .to_face()
+            .extrude(dvec3(0.0, 0.0, -(hook_thickness + wire_gap)))
+            .into();
+
+        let hook_bottom = hook.faces().farthest(Direction::NegY);
+
+        let hook_descent = hook_bottom
+            .workplane()
+            .translated(dvec3(0.0, -(hook_thickness + wire_gap) / 2.0 + hook_thickness / 2.0, 0.0))
+            .rect(40.0, hook_thickness)
+            .to_face()
+            .extrude(dvec3(0.0, -20.0, 0.0))
+            .into();
+
+        hook = hook.union(&hook_descent).into();
+
+        let bottom_hook_edges =
+            hook.faces().farthest(Direction::NegY).edges().parallel_to(Direction::PosZ);
+        hook = hook.fillet_edges(10.0, bottom_hook_edges);
+
+        case_box = case_box.union(&hook);
+    }
+
+    // Punch some holes in the back for optional zipties
+    for x_offset in [-100.0, -50.0, 0.0, 50.0, 100.0] {
+        let ziptie_hole = bottom_face
+            .workplane()
+            .translated(dvec3(x_offset, -20.0, 0.0))
+            .circle(0.0, 0.0, 2.25)
+            .to_face()
+            .extrude(dvec3(0.0, 0.0, 10.0))
+            .into();
+
+        case_box = case_box.subtract(&ziptie_hole)
+    }
+
+    // Cut out a circle on the front
+    let front_face = case_box
+        .faces()
+        .farthest(Direction::PosZ)
+        .workplane()
+        .translated(dvec3(0.0, 75.0, 0.0))
+        .circle(0.0, 0.0, 100.0)
+        .to_face();
+
+    front_face.subtractive_extrude(&case_box, -case_thickness)
+}