Measured, not estimated
The geometry is derived from the photograph rather than inferred from what rooms usually look like, which is why the result matches the property.
The core of it
The part that does not change.
Before anything is generated, Miravely reads the wall junctions, window openings, door positions and ceiling height out of your photograph and holds them. Everything else is free to move.
It fails loudly
If the photograph is too dark or too tight to read a structure from, Miravely says so instead of quietly inventing one.
You can switch it off
For early concept work you can release the lock deliberately. It is a decision you make rather than a thing that happens to you.