Spaces are part of our paid subscription plans.
Architecture is all about creating spaces that we inhabit (maybe this is why we decided on our product name)
In the conceptual design stage however you need the flexibility to define spaces in different ways, ie you may be working more on overall areas as opposed to individual rooms and spaces.
Spaces provides you the flexibly you need and when combined with the usage or requirements provides valuable data feedback as you develop you design.
To create a building with spaces you need to firstly ensure that the Create items automatically is disabled in the Drawing settings:
You then sketch out your building along with strokes to define broad areas or individual spaces:
Once you're happy with the approximate layout make sure you are on the Building tool and then tap inside the building to have the building and spaces created: