1. Select the components or areas where diagonal lines need to be added, such as walls and floors.

2. Enter the profiling mode, select "Fill" or "Shape" in the toolbar, and then select the "Oblique Fill" option.

3. Select the type of diagonal, such as straight line, point and circle, and set the angle and spacing of diagonal.

4. Select the area where diagonal lines need to be added in the profile, and then daub or fill it with the mouse to add diagonal lines.

5. Make adjustments as needed, such as changing the color, thickness and line type of the diagonal.

6. When finished, save the outline and insert the pattern filled with diagonal lines where necessary.