From bd5a1b5bdaa9d793b2b6c9ebb30a8e2a6bf21ffb Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Thu, 30 Oct 2025 18:35:20 +0100
Subject: [PATCH] Account 2x3/4 differences in
 Shading/Rendering::Transparency()

---
 src/ifcgeom/mapping/mapping.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/ifcgeom/mapping/mapping.cpp b/src/ifcgeom/mapping/mapping.cpp
index 8c130aa5f6..f98bfe232d 100644
--- a/src/ifcgeom/mapping/mapping.cpp
+++ b/src/ifcgeom/mapping/mapping.cpp
@@ -670,12 +670,23 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcSurfaceStyle* style) {
         if (rendering_style->TransmissionColour()) {
             // Not supported
         }
+#ifndef SCHEMA_IfcSurfaceStyleShading_HAS_Transparency
+        // ifc2x3
         if (rendering_style->Transparency()) {
             const double d = *rendering_style->Transparency();
             surface_style->transparency = d;
         }
+#endif
     }
-    
+
+#ifdef SCHEMA_IfcSurfaceStyleShading_HAS_Transparency
+    // ifc4 and onwards
+    if (shading->Transparency()) {
+        const double d = *shading->Transparency();
+        surface_style->transparency = d;
+    }
+#endif
+
     return surface_style;
 }