Fix error when enabling Mist pass but there was no world. Can't find mist settings, so check for World first.

1 files changed, 4 insertions, 3 deletions

diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py
index 6c7c66d14fb..6ef8aa7611e 100644
--- a/intern/cycles/blender/addon/ui.py
+++ b/intern/cycles/blender/addon/ui.py
@@ -885,9 +885,10 @@ class CyclesWorld_PT_mist(CyclesButtonsPanel, Panel):
     @classmethod
     def poll(cls, context):
         if CyclesButtonsPanel.poll(context):
-            for rl in context.scene.render.layers:
-                if rl.use_pass_mist:
-                    return True
+            if context.world:
+                for rl in context.scene.render.layers:
+                    if rl.use_pass_mist:
+                        return True
 
         return False