1. Create a Tube object, at menu 'Objects' > 'Primitive' > 'Tube'. Use the value as follow, Inner Radius: 172m, Outer Radius: 200m, Rotation Segments: 32, Height: 30m. With the Tube object selected, select menu 'Functions' > 'Make Editable'.

2. Select menu 'Selection' > 'Rectangle Selection'. At the Attributea manager, uncheck the 'Only Select Visible Elements' radio button. Then select a half bottom part of the tube.

3. Select menu 'Tools' > 'Edges', then select the bottom edges as follow.

4. Select menu 'Structure' > 'Extrude', then select and drag manualy the selected area to the bottom direction. Just arrange the height of the window as you want.

5. Select menu 'Structure' > 'Knife'. At the Attributes Manager select 'Plane' at the 'Mode' drop down menu. Select X-Z coordinate. Create 4 cuts as pointed as follow.

6. Use 'Tools' > 'Polygons'. Select the pointed area as follow.

7. Use menu 'Structure' > 'Bridge'. We are going to connect the selected area. Make sure you begin to click the same point as you end your click. For example, if you begin at point A1, end it at A2.

8. Use same method to another 2 parts.

9. Now, select the pointed area as follow.

10. Use Knife tool, select Plane mode and check the 'Restrict To Selection' radio button.

11. Create 2 cuts as pointed.

12. Now connect the selected area using Bridge Tool.

13. Do the same to the another part.

14. Sellect the surounded area as pointed. Select menu 'Structure' > 'Bevel'. Use the same value as shown on image, Maximum Angle: 91, Extrusion: 7m, Inner Offset: 5m

15. Use the same method and value to the selected area.

16. We have the bottom part of the window unclosed. To close the hole, right click and pick close hole.

As usual, you can use material from Cinema 4D Content Browser.