If the gate was closed and facing you all the bars would be parallel to each other ( of course they could be bent or even missing but lets assume it’s a new one!). Once the gate is opened the bars are now at an angle to you and will converge if you could extend them at a point called the vanishing point. I have drawn this on the reference and called it VPt. The vanishing point will always be on your eye level ( some things you just have to acccept). I have drawn eye level on the reference. You can do similar constructions with the sides of houses that are at an angle to you. I am sure you have seen diagrams in learn to paint books. An understanding of these simple rules of perspective will really help with your drawing skills.
Posted in Painting tips & techniques.