Why is there a figure in the building when the window sill height is not 0?

This is because the elevation of the platform at the bottom of the building is set to other heights, which makes the model look "empty" and the analyzed graphics naturally pass through.

Solution: 1 Add the building model as a solid under the current elevation of the building so that light cannot penetrate; 2. Adjust the elevation at the bottom of the building model back to 0.