Please review the images below. This study was produced using AutoCad extruded masses and the slice command for the sky exposure plane. You can use any program you are comfortable with – but this tutorial will help you understand the steps.
This is intended as an example of how to apply and model based on the sky exposure planes. This sample does not consider if this zoning envelope has setbacks which wrap up along the side yards or has rear yard requirements – be certain you check this for your own site.
In this example the building site is 200′ x 100′ and has a narrow street frontage along the 200′ length and a wide street frontage along the 100′ length. The setbacks are 20′ for narrow and 15′ for wide and the sky exposure is 2.7 to 1 for narrow and 5.6 to 1 for wide.
I began by creating the 85 foot base and then with setbacks a tower that continues up high enough that the sky exposure planes will not create a flat top. I also created the two sky exposure planes in advance – each at the correct slopes.