From 5e4684303155047a078dbca2dcc53dc45b817081 Mon Sep 17 00:00:00 2001
From: tetektoza <tetektoza@gmail.com>
Date: Sun, 11 May 2025 21:31:15 +0200
Subject: [PATCH] BIM: Change from RGBT to RGBA for IFC

Currently users by default have transparent window frames and doors.

Turns out that at some point there was a switch from RGBT to RGBA, which
means last transparency element differs in the range of transparency
that it specifies (RGBT, where 1 - fully visible, RGBA where 1 - fully
transparent). As the changed happened, all of the windows and door
became transparent.

This patch changes that, from RGBT to RGBA so we will map transparency
properly, as well as adding a possibility to set transparency through
material.
---
 src/Mod/BIM/importers/exportIFC.py       |  1 +
 src/Mod/BIM/importers/exportIFCHelper.py | 16 ++++++++--------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/Mod/BIM/importers/exportIFC.py b/src/Mod/BIM/importers/exportIFC.py
index 74208443f6..a12fbda457 100644
--- a/src/Mod/BIM/importers/exportIFC.py
+++ b/src/Mod/BIM/importers/exportIFC.py
@@ -2346,6 +2346,7 @@ def getRepresentation(
                     if hasattr(obj,"Material"):
                         if obj.Material:
                             m = obj.Material.Label
+                            rgbt[i] = (rgbt[i][0], rgbt[i][1], rgbt[i][2], obj.Material.Transparency/100.0)
                     psa = ifcbin.createIfcPresentationStyleAssignment(m,rgbt[i][0],rgbt[i][1],rgbt[i][2],rgbt[i][3])
                     surfstyles[key] = psa
                 isi = ifcfile.createIfcStyledItem(shape,[psa],None)
diff --git a/src/Mod/BIM/importers/exportIFCHelper.py b/src/Mod/BIM/importers/exportIFCHelper.py
index d4e6feb2b3..d044269850 100644
--- a/src/Mod/BIM/importers/exportIFCHelper.py
+++ b/src/Mod/BIM/importers/exportIFCHelper.py
@@ -381,13 +381,13 @@ class recycler:
                 self.rgbs[key] = c
             return c
 
-    def createIfcSurfaceStyleRendering(self,col,trans=0):
+    def createIfcSurfaceStyleRendering(self,col,trans=1):
         key = (col.Red,col.Green,col.Blue,trans)
         if self.compress and key in self.ssrenderings:
             self.spared += 1
             return self.ssrenderings[key]
         else:
-            if trans == 0:
+            if trans == 1:
                 trans = None
             c = self.ifcfile.createIfcSurfaceStyleRendering(col,trans,None,None,None,None,None,None,"FLAT")
             if self.compress:
@@ -405,7 +405,7 @@ class recycler:
                 self.transformationoperators[key] = c
             return c
 
-    def createIfcSurfaceStyle(self,name,r,g,b,t=0):
+    def createIfcSurfaceStyle(self,name,r,g,b,a=1):
         if name:
             key = name + str((r,g,b))
         else:
@@ -415,22 +415,22 @@ class recycler:
             return self.sstyles[key]
         else:
             col = self.createIfcColourRgb(r,g,b)
-            ssr = self.createIfcSurfaceStyleRendering(col,t)
+            ssr = self.createIfcSurfaceStyleRendering(col,a)
             c = self.ifcfile.createIfcSurfaceStyle(name,"BOTH",[ssr])
             if self.compress:
                 self.sstyles[key] = c
             return c
 
-    def createIfcPresentationStyleAssignment(self,name,r,g,b,t=0,ifc4=False):
+    def createIfcPresentationStyleAssignment(self,name,r,g,b,a=1,ifc4=False):
         if name:
-            key = name+str((r,g,b,t))
+            key = name+str((r,g,b,a))
         else:
-            key = str((r,g,b,t))
+            key = str((r,g,b,a))
         if self.compress and key in self.psas:
             self.spared += 1
             return self.psas[key]
         else:
-            iss = self.createIfcSurfaceStyle(name,r,g,b,t)
+            iss = self.createIfcSurfaceStyle(name,r,g,b,a)
             if ifc4:
                 c = iss
             else: