Firstly, I used " Line" with "Smooth" setting to draw out the outline of the structure.
The vertex points of line had been adjusted to make the structure look nice.
I continued with the second line. Same as the first line, vertex points of the second line were modified. When both lines were ready, "Attach" from modification panel had been chosen. By doing this the two lines will merge to each other and become one image.
Then, "Extrude" from modification panel had been used. This will visualise the line and makes it looks real.
A cylinder and a rectangular box were drawn.
Now the drawing is done. I spent some time to make some final adjustment such as selection of the suitable colour and modify its tone to make it look alike with the sample picture.
