Creating windows in a 3d shape (specifically cylinder)

I am brand new to AutoCAD and could use some advice. Attempting to do a rendition of the Tower of Babel for an extra credit assignment. While I know what I currently have looks a little sloppy, I'm mainly just interested in being able to cut window shapes out of the cylinders (specifically arched windows). Even just a simple explanation of how to possible draw an arched shaped in 3 dimension on these cylinder faces and then use some sort of extract/extrude/subtract command would be incredibly helpful. Attached is what I have so far. Thanks to anyone who takes the time to help out.

Babel_1.dwg

Welcome to CADTutor.

Forget about drawing the window shape on the cylinders.

Typically in Autocad modeling we draw things in 2D, then use that drawing to help us generate a 3D entity.

Draw the window in the X,Y plane, using the PLINE command.

Start at the lower left corner and turn on your ORTHO, draw a staight segment of an appropriate length up to represent the side of the window, then hit A for arc, and define the arched segment at the top of the window, then hit L for the linear segment coming down the other side of the window the same distance, then hit C for CLOSE, and the Polyline will be closed and your window shape should be good to go.

This shape will be the basis for a tool, which you will create by using the EXTRUDE command.

Save a copy of your window shape, so you don't need to recreate it. You will need one of these tools for each opening you will create. When using the SUBTRACT command it will be deleted.

Extrude it to an arbitrary length which is definitely greater than the diameter of the tower, where you want to use it, or just longer than the tower is wide at the widest point (that is assuming that you want the windows to pierce through the level, you might not).

You will then need to position the SUBTRACT SHAPE to wherever you want to use it.

The ALIGN or 3DALIGN command may prove helpful, if you have a problem orienting them to your model

Look at Modelspace from a few different perspectives to make sure it is where you think it is, then use the SUBTRACT command, and follow the commandline prompts, and you should be good.

I suggest turning off the REALISTIC visual style, and would personally use the 2D Wireframe visual style at this point.

Remember, looking at what is going on from different perspectives in Modelspace is highly recommended.

I don't know too much about the Tower of Babel, but was it really only about 216 inches tall?

With a maximum diameter of 265 inches? Those dimensions strike me as somewhat less than Biblical in stature, although I could be wrong.

If I were you, I would save a copy of your file, and experiment with the Windows on it.