First angle orthographic projection symbol construction

The symbol for first angle orthographic projection a simple explanation for Engineers.

[@kevkokip]

Use any Diameter for outer circle and the inner circle should have a diameter of half the bigger circle.

[@kevkokip]

The length of the funnel-like part is equal to your DIAMETER of bigger circle

[@richmonddelossantos2520]

What site are you using to create that

[@kevkokip]

here is the link to the online tool i used www.mathspad.co.uk/i2/construct.php