Convert to Sheet Metal takes bent parts as modelled: radius and chamfer bends, holes (#1314)

A Convert to Sheet Metal bend point can now lie on a bend modelled with its radius (a cylinder tangent to two flat faces) or in the middle of a chamfer; either becomes one bend at the faces' virtual sharp, with the rule's radius. Holes and engravings carry over. Bend points on edges convert as before. Recorded under format 21. Tests in cmd::sheet::convert_tests; the sheet-metal guide is updated.

crates/doc/src/sheet.rs

@@ -19,6 +19,7 @@ use crate::{DocError, Document, IDENTITY, Mat, Result, apply_point, apply_vector
 #[path = "sheet_convert.rs"]
 mod convert;
 pub use convert::{bend_edge_names, convert_body};
+pub(crate) use convert::{outline_loop, round_wall};
 
 // Bound the aggregate geometry, including sampled curves and intermediate clipping pieces.
 // These are work limits, never geometry truncation: a larger input returns a useful error.
@@ -446,6 +447,10 @@ pub struct SheetFlange {
     /// instead of a rectangle `leg` long.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub shape: Option<Vec<Vec2>>,
+    /// A converted face's panel as drawn: `shape` with arcs where the face's edges are round
+    /// (flat coordinates, counter-clockwise).
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub exact: Option<Loop2>,
     /// Which feature made it: `F<feature>.<k>` (persistent edge names).
     #[serde(default, skip_serializing_if = "String::is_empty")]
     pub tag: String,
@@ -842,6 +847,9 @@ impl SheetBody {
 
     /// Flat region of a flange's panel.
     pub fn panel(&self, f: &SheetFlange) -> Region2 {
+        if let Some(lp) = &f.exact {
+            return Region2 { outer: lp.ccw(), holes: Vec::new() };
+        }
         if let Some(sh) = &f.shape {
             return Region2 { outer: Loop2::polygon(sh).ccw(), holes: Vec::new() };
         }
@@ -2167,6 +2175,7 @@ impl SheetBody {
                 radius,
                 leg: leg.max(0.0),
                 shape: None,
+                exact: None,
                 tag: String::new(),
                 ext: (0.0, 0.0),
                 slope: (0.0, 0.0),
@@ -2899,6 +2908,7 @@ impl SheetBody {
             slope: (0.0, 0.0),
             tear: (false, false),
             shape: None,
+            exact: None,
             tag: String::new(),
         });
         Ok(self.flanges.len() - 1)
@@ -3033,6 +3043,7 @@ impl SheetBody {
             slope: (0.0, 0.0),
             tear: (false, false),
             shape: None,
+            exact: None,
             tag: String::new(),
         };
         let ba = self.allowance(&probe);
@@ -3097,6 +3108,7 @@ impl SheetBody {
             Some(j) => {
                 if let Some(f) = self.flanges.get_mut(j) {
                     f.shape = Some(ccw(fixed_part.clone()));
+                    f.exact = None;
                 }
             }
         }
@@ -3113,6 +3125,7 @@ impl SheetBody {
             slope: (0.0, 0.0),
             tear: (false, false),
             shape: Some(ccw(moving)),
+            exact: None,
             tag: String::new(),
         });
         let i = self.flanges.len() - 1;
@@ -3238,6 +3251,7 @@ impl SheetBody {
             Some(j) => {
                 if let Some(f) = self.flanges.get_mut(j) {
                     f.shape = Some(ccw(fixed));
+                    f.exact = None;
                 }
             }
         }
@@ -3256,6 +3270,7 @@ impl SheetBody {
                 slope: (0.0, 0.0),
                 tear: (false, false),
                 shape: Some(ccw(moving)),
+                exact: None,
                 tag: String::new(),
             });
         }
@@ -4055,6 +4070,7 @@ pub fn contour_flange(body: &str, rule: &str, rv: &RuleValues, plane: &Plane, pt
             slope: (0.0, 0.0),
             tear: (false, false),
             shape: None,
+            exact: None,
             tag: String::new(),
         };
         let ba = sheet.allowance(&f);