How to Draw a Cylinder
A cylinder is one of the easiest geometrical solids to develop using graphical methods. To start with you should draw your cylinder in both plan and elevation. Then divide your plan view (which should be a circle) into equal segments. You can project these divisions to the elevation but this is not necessary (note if you do this it will be good practice for more complex solids to develop). I have divided my cylinder plan up into twelve (12) equal segments as shown below.
Now use your compass to start laying out the development. On a piece of paper mark a start point with an X. Now get your height from the elevation and scribe an arc in the vertical plain. Draw a vertical line from your start point to intersect your arc line.
Now lets get the length of your developed cylinder. Firstly draw a long horizontal line from the previous start point. Now to obtain the developed length of the cylinder measure off one of your plan view divisions with a compass and scribe an arc in the horizontal plain from the start point. You will have to repeat this by how many division that you have, using each small arc as your next starting point. Please refer to the diagrams below for details on this process.
The diagram below shows the developed height scribed in the vertical plain and the developed length shown in the horizontal plain. This is your finished developed cylinder. Note that the more divisions that you make in the plan view, then the more accurate your development will be.
A simple formula to check the accuracy of the length of your cylinder is:
Circumference = phi x diameter (where phi = 3.1415)