Cut the crossing roofs
- Activate the model window. Select File > Switch Between 2D and 3D.
- Rotate the model to an appropriate position.
- Select
Roofs > 
Clip Roofs,
Both to Clip. - Select the first slopes to be cut. Hold down the Ctrl key, and select the roof slopes (A) and (B).
- Select Confirm.
- Select the second slopes to be cut. Select the main roof slope (C).
- Select Confirm.
- Quit by pressing the Esc key.
