For this tutorial we need to know how the multi-subobject
and polygon ID works.
1. Prepare a
multi-subobject material before drawing.
Material ID 1 = wall
Material ID
2 = ceiling
Material ID
3 = floor
. . . and etc.
2. Draw a box,
convert to poly and flip all polygon's normals.
3. Create a
camera inside and change a viewport to be the camera view.
Assign material IDs to each polygon by following the materials that we have
already
prepared.
In this stage
I put ID 1 for whole wall, ID 2 for the ceiling and ID 3 for the floor.
The important thing is to assign material IDs to polygons
in the beginning rather than later, as the
finished model might be more complex and it could be more difficult
to select polygons.
4. work on edge
sub-object, select edge and connect. This is for creating window and door
Tip: Avoid using
slice tool in editable poly/mesh by using connect edge instead, as incorrect
uvwmap coordination may sometimes appear on the sliced polygon when we
apply face UVWmap to it.
5. Connect edge
again. 2 segments divided horizontally for a window in the left and 1 segment
divided for a door in the right.

6. Adjust the
selected edges height to the same as window and door.
7. Go to polygon
sub-object and extrude the selected polygons to create wall thickness
and then assign Material ID =4 (Material ID 4 = window frame) to the
extruded polygons.

8. Connect the
selected edges

9. Select the polygons
and inset. This is to
create the width of window
and door frame.

10. Go to the door
polygon and move it down as we don't need the door step.
11. Extrude polygons to create the thickness of door and window. Then assign
number ID 5 for the extruded polgons window and number 6 for polygon door.

12. Select the
polygons and delete the overlaping polygons at the door step that we don't
need. Go to the Border sub-object and cap the hole again. A new
clean polygon will be created at the foot of the door.
13. The model has been finished and we can now check the
material IDs on each polygon.

14. Select each polygon
and apply UVWmap.
15. The finished scene lit with lighting techniques from
the first 3 tutorials.