A lot of people want to see the endresult, pictures say more then a technical drawing. Sometimes it is also wise to have a picture to know for sure that it is what the client wishes.
From getting a picture for something that doesn't exist is visualise a handy help. This is useful in the quotation stage, a 3D drawing (if necessary photo realistic) of the design says more then a technical drawing.
I can make such a drawing for you. I work with Innovate, a 3D Cad software which is very good with realistic photo's.
To make a drawing, a simple sketch, a technical drawing or just the discription of a idea is enough.