Rooms and analytical surfaces

[SUSANA123]

Hello,

I would like to ask for help.

I would like to save a Revit design as a gbxml file. I have seen that the volume limited by the rooms I draw is very different from the one produced by the analytical surfaces. I have read that a little difference between them is usual, but I think that, in this case, it changes too much and I do not know if I have made something wrong.

I attach the two images. Its Revit 2019.

Thank you very much for your help and your time.

[ToanDN]

Did you create the roof by face from a mass?  Create it as two separate half-dome roofs, not one complete dome roof (pick one surface then create roof, them repeat).