Cannot place a wall register on a soffit

[mgianzero]

I'm trying to place wall ventilation register on the end of a soffit in a room.  But HDP will not allow me to do this.  I can only install the register on the wall below.

 

Soffits are usually used to hide ventilation ducts which connect to registers.  Why can't I do this?

 

See my pic as an example.

[solver]

21 minutes ago, mgianzero said:

Soffits are usually used to hide ventilation ducts which connect to registers.  Why can't I do this?

 

Because soffits are just a box shape with a few special properties. They are not walls.

 

Try placing a register away from a wall. Then manually position it -- rotate/drag, open it and set the height.

[mgianzero]

Okay.  I actually thought that interior wall soffits (from Build->Cabinet->Soffit) was actually considered a wall, such as over a wall cabinet or below the ceiling on a wall.

 

Any ways, I was able to drag the register away from a lower wall to then move it onto the soffit above.

 

Thanks!