Struggling with 'use soffit surface for ceiling'

[ChiefRushT]

I'm working on a design for our next home build.  It'll be a hybrid timber frame, and I'm trying to use 'use soffit surface for ceiling' to create the effect of planking for the ceiling.  I have a celestory style upper floor with a 'catwalk' on either side side.  The second floor has a room that's 'open below'.  The two roof planes have identical settings.  For the life of me, I can't seem to get both roof planes to show the planking at the same time.

 

I'm early in the process and just getting structure down, so just ignore the aesthetics for now please

 

Thoughts anyone?

 

<edit>  HDP2024

 

 

[Jo_Ann]

???

Unclear what you did or what you want?

[ChiefRushT]

The left roof plane shows the osb layer, the right roof plane shows the soffit material which I have set to some planking.  The view here is from the first floor looking through the second floor opening, to the second floor roof.  Notice that left side shows OSB, right side shows planking.  Yet, settings for both roof planes are identical.

 

Appreciate the consideration.

 

 

[Rookie65]

Do you have a ceiling thickness set up? If so, that would be where you'd put the ceiling material 

[Jo_Ann]

On the 2nd floor, open the "open below" room dialog, and uncheck "ceiling over this room."
Open the materials dialog and select the planking for the ceiling finish.

Open the "cat-walk room" and follow the same steps.