From d12124073c4f4f70b8fd2f2a7bfd14a3bf9eeec9 Mon Sep 17 00:00:00 2001
From: WandererFan <wandererfan@gmail.com>
Date: Mon, 13 Apr 2020 22:31:18 -0400
Subject: [PATCH] [TD]Piecewise Sectioning Algo

---
 src/Mod/TechDraw/App/DrawViewSection.cpp | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/Mod/TechDraw/App/DrawViewSection.cpp b/src/Mod/TechDraw/App/DrawViewSection.cpp
index d3cb579bb6..0d76ef8ec9 100644
--- a/src/Mod/TechDraw/App/DrawViewSection.cpp
+++ b/src/Mod/TechDraw/App/DrawViewSection.cpp
@@ -347,7 +347,6 @@ App::DocumentObjectExecReturn *DrawViewSection::execute(void)
         }
     }
 
-
     dvp->requestPaint();  //to refresh section line
     return DrawView::execute();
 }
@@ -382,13 +381,26 @@ void DrawViewSection::sectionExec(TopoDS_Shape baseShape)
     BRepBuilderAPI_Copy BuilderCopy(baseShape);
     TopoDS_Shape myShape = BuilderCopy.Shape();
 
-    BRepAlgoAPI_Cut mkCut(myShape, prism);
-    if (!mkCut.IsDone()) {
-        Base::Console().Warning("DVS: Section cut has failed in %s\n",getNameInDocument());
-        return;
+    BRep_Builder builder;
+    TopoDS_Compound pieces;
+    builder.MakeCompound(pieces);
+    TopExp_Explorer expl(myShape, TopAbs_SOLID);
+    int indb = 0;
+    int outdb = 0;
+    for (; expl.More(); expl.Next()) {
+        indb++;
+        const TopoDS_Solid& s = TopoDS::Solid(expl.Current());
+        BRepAlgoAPI_Cut mkCut(s, prism);
+        if (!mkCut.IsDone()) {
+            Base::Console().Warning("DVS: Section cut has failed in %s\n",getNameInDocument());
+            continue;
+        }
+        TopoDS_Shape cut = mkCut.Shape();
+        builder.Add(pieces, cut);
+        outdb++;
     }
 
-    TopoDS_Shape rawShape = mkCut.Shape();
+    TopoDS_Shape rawShape = pieces;
     if (debugSection()) {
         BRepTools::Write(myShape, "DVSCopy.brep");            //debug
         BRepTools::Write(aProjFace, "DVSFace.brep");          //debug