# Depth by Diagonals: method II

As discussed last week, the current section of the book Successful Drawing which I am reviewing, deals with some of the drafting rules for determining the depth of an object by casting diagonal lines.  Last week we covered the first method, and this posting then will explain Loomis’ second method which is outlined in the text.

## The use of the bisecting vertical

This method is very similar to the one outlined in the previous posting, but here, Loomis introduces a few more ‘controls’ to make certain that the placement of receding points are accurate.  He advocates for the use of a bisecting vertical to be placed along the horizon line, to keep everything accurate.  I find this method to be very useful for drawing buildings, with repeating surface features, such as windows, facade details, or columns on ancient buildings.  Let’s get into it.

1. First, let us consider that you are trying to draw a building, with a series of columns located in regular intervals along the side of it, going off into the distance.  First, create the near corner height of the plane you wish to decorate, and sight the V.P.
2. Now, the artist must place the ending of the facade plane at what Loomis calls the optional depth.  This is the most unscientific part of his instruction, because it leaves the artist to place the second line by eyeball.  He uses the word optional not in the sense that one may draw it or not draw it, but instead Loomis means where the line is drawn is optional, i.e. it is up to you.  Once the visual depth chosen pleases the artist’s eye, he has created a section. The second line drawn is called the Terminus Line, as it delineates where the section terminates.  This section is now easily cloned in perspective.
3. Now, the next step is the technical part of the procedure.  The artist casts lines diagonally through the section, starting at the near top and bottom corners and extending through their diagonally opposing corners. Following that, a vertical line must be drawn bisecting the horizon perpendicularly, through the V.P.  The diagonal lines must extend far enough to reach the point where the new vertical line delineates.  Mark the points where the diagonals cross the vertical.  Let us call the new high and low points, the Vertical Points.
4. This X of diagonal lines shows the centre of the section, and sets the artist up to clone the depth for the following section.
5. To find the depth of the second section, the artist again casts new diagonals, but this time he must start from the top and bottom of the newly drawn Terminus Line of the established section.  These lines are cast diagonally up and down to both the high and low Vertical Points,  This will create another X within the Lines of Perspective.
6. A new Terminus Line is drawn vertically where the diagonals cross the Perspective Lines, and a second section is established.
7. Repeat from step 5, casting diagonals to the Vertical Points.  The sections will be drawn in their proper visual depth as per the laws of perspective.
8. These sections could delineate where a repeating surface feature is found on a building, such as a column or any regular repeating element, including doors, windows and other architectural features.  This method is even useful for drawing a series of parked cars along the sidewalk, since many cars are relatively the same length, the sections can represent the cars’ body length.  Any anomalies of vehicular type can be adjusted for as needed.

This concludes our posting of Understanding Loomis.  Next week’s post will again unpack another of Andrew Loomis’ methods of finding depth by diagonals.  Stay tuned.