How to 3D-Model Basic Windows and Other Openings
Boolean is the Key
Openings can be created in a number of ways. If you do want them to be part of the actual model – instead of a skin for a flat surface of your model – you will to have to use Boolean operations so as to subtract forms out of the main surface of your exterior wall.
First Step in Modeling a Window
The most straightforward way to do this – provided you are using a modeler which is good at Boolean operations; in Blender any version after 2.76 will do – is to start with a cylinder. You then go into Edit mode, and extrude the vertices highlighted in Figure A.
After you extrude them, along the vertical Axis, you create a new surface (a parallelogram). This is shown in Figure B.
Second Step in Modeling a Window
You now must erase the vertices not needed in what originally had been a cylinder. Those are the ones highlighted in Figure C.
After they are taken out, select the entire object and fill it in (if you are using Blender, just press the “F” key). The result is a compact volume, presented in Figure D.
Third Step in Modeling a Window
If we just wanted to create openings, we could use the shape we already have created, and substract it from our model, using Boolean Operations.
In this example, the basic exterior of the Byzantine Chapel modelled in a previous part of this tutorial series is used. The window-shaped volumes are ready to be subtracted from the walls (Figure E).
Since, however, we aim to model windows, instead of merely creating openings on a wall, we move on to construct a surrounding part of the window.
This is easily done by enlarging the original window-like volume we made, and placing the new form behind the other one. In this example the new volume is 1.1 times enlarged, and is now placed behind the part meant to be subtracted from the building. (Figure F).
Final Step in Modeling a Window
All that remains is to subtract the forms from the main model.
You should first subtract the smaller window-like volumes, from the larger ones created in the previous step. Then subtract the new shape from the walls of your model (in this case, from the exterior of the Byzantine Chapel).
The result is shown (done for the right side of the model) in Figure G...
It is important to use later versions of Blender, when you are subtracting groups of forms from other forms. This is so because in versions before 2.76 you were not given the choice to select a relatively smaller level of accuracy in the Boolean Operations (some margin of error), and the result was often that Blender could not handle the operations if many forms were involved, or if their placement to each other was problematic in one way or other (having to do with symmetries).
Fortunately this issue is no more in the recent versions! By now you can even join all shapes you wish to subtract, and then run the boolean operation on intricate volumes, without running the risk of a failed Boolean Operation!
© 2018 Kyriakos Chalkopoulos