From 2e5308a35f394445610748e2892678e02d0af964 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=8C=82=E4=B9=8B=E9=92=B3?= <claw@hdtime.space>
Date: Fri, 24 Jul 2026 06:18:55 +0000
Subject: [PATCH] =?UTF-8?q?fix:=20step=5Fimport=20=E2=80=94=20NurbsSurface?=
 =?UTF-8?q?=20not=20default-constructible?=
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---
 src/brep/step_import.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/brep/step_import.cpp b/src/brep/step_import.cpp
index 4bebf38..54555c8 100644
--- a/src/brep/step_import.cpp
+++ b/src/brep/step_import.cpp
@@ -1264,7 +1264,10 @@ private:
         }
 
         const auto& ent = entities_.at(ref);
-        curves::NurbsSurface ns;
+        // Default-construct with a dummy surface (NurbsSurface has no default ctor)
+        std::vector<std::vector<Point3D>> g0 = {{Point3D(0,0,0), Point3D(1,0,0)},
+                                                 {Point3D(0,1,0), Point3D(1,1,0)}};
+        curves::NurbsSurface ns(g0, {0,0,1,1}, {0,0,1,1}, {}, 1, 1);
         try {
             if (ent.type == "PLANE")
                 ns = build_plane_surface(ref);