Fix confusing transparency attribute in add style API usecase. See #1529.

src/blenderbim/blenderbim/bim/module/style/operator.py

@@ -10,6 +10,7 @@ def get_colour_settings(material):
         bsdf = material.node_tree.nodes["Principled BSDF"]
         transparency = bsdf.inputs["Alpha"].default_value
         diffuse_colour = bsdf.inputs["Base Color"].default_value
+    transparency = 1 - transparency
     return {
         "surface_colour": tuple(material.diffuse_color),
         "transparency": transparency,

src/ifcopenshell-python/ifcopenshell/api/style/add_style.py

@@ -23,7 +23,7 @@ class Usecase:
             "IfcSurfaceStyleRendering",
             **{
                 "SurfaceColour": self.create_colour_rgb(self.settings["surface_colour"]),
-                "Transparency": (self.settings["transparency"] - 1) * -1,
+                "Transparency": self.settings["transparency"],
                 "ReflectanceMethod": "NOTDEFINED",
                 "DiffuseColour": self.create_colour_rgb(self.settings["diffuse_colour"]),
             }