You've heard about 2 point perspective at least once. Basically, there are two vanishing points rather than one, where all of the perspective lines will intersect, and in return, gives the composition a proper spacial perspective.
For a simple background without too much technical accuracies, there is no substitute for getting the 2 point perspective up and running on the canvas. There are various methods of doing so which is dependent on the software being used. However, there are limitations.
In Photoshop specifically, there is the 'vanishing point' filter. Unfortunately, this is only used to put flat textures into perspective of an existing picture. In other words, this does very little to help with the initial setup of creating a perspective grid.
Therefore, knowledge of manually setting up the grid is essential not only for Photoshop, but is also helpful if the artist is cross-referencing other drawing platforms. The best way to start off the 2 point perspective grid is with a very large canvas.
In any drawing, vanishing points will always appear outside of the designated drawing. By drawing these perspective lines on an extremely large canvas as a separate file, it can then be imported back into a smaller drawing canvas.
The ideal ratio is to draw a perspective grid that is about at double the intended canvas of the artwork. For example, if a painting is 1000 pixels wide, then vanishing point A should be 2000 pixels away from vanishing point B at the minimum.
This is to help give a natural perspective to the background drawing that doesn't look like it has any camera distortion from having the vanishing points being too close. Anyway, once a new blank canvas file is opened up, start the process by creating a box with the rectangular marquee tool.
On a new layer, go to Edit > Stroke to fill in the outlined square. The reason is that a square is the optimal shape for measuring as well as the needed shape in creating a grid. With the square shape still selected, go to Edit > Define Pattern.
Go ahead and define the square as a new pattern. It may seem weird at first trying to understand why a pattern is needed to create a 2 point perspective grid, but there is a method to the madness. Just make sure that there are no other textures under the selected area as we want it to be transparent.
When ready, go to Edit > Fill at the top menu. Immediately, a new window will open up asking the user what parameters to use when filling out the canvas. Since we already defined the pattern, It should be clear as to what will happen next.
Under the 'Use' category, go ahead and select the pattern option. After that, click the pattern box and look for the square that was made in the previous step. It should always be the last box in the list of available patterns.
Once selected, choose the blend mode. 'Normal' is fine as we don't require anything special. Opacity is self explanatory. What we have to be aware of is the option that says 'Preserve Transparency.' Make sure that this is checked off.
When ready, hit the 'OK' button. The end result should be an entire canvas filled with the square, which make it look like a grid, on a new layer. If the grid holes seem too big or too small, there is always the option to change its scale.
Now that the hard part is done, this next step is relatively easy. The end result is to give this flat grid perspective. The quickest way is to use the transform options available in Photoshop. However, before that, we need to turn it into a smart object.
The main advantage of a smart object is that it allows scaling, up to its maximum original size, without any loss of quality. This is great to prevent pixelation when returning to its original size when experimenting with smaller scaling. The downside is that the artist can no longer draw on it.
To do that, right click on the layer and simply select 'Convert to Smart Object'. Luckily, this isn't a one way street. If there is any need to draw on it again, just simply hit the option saying to 'Rasterize Layer'. Again, just make sure it's done on its original size to prevent pixelation.
After that, go to Edit > Transform > Perspective to skew the grid it in the right direction. Automatically, it will calculate the square sizes based on the perspective amount. Finally, duplicate and flip the new perspective grid so now the 2 point perspective grid goes in both directions.
Now that the perspective grid has been made, it can be imported to any other future artworks. If the new artwork is done in Photoshop, simply move the grid layers into the new painting file. For all other types of drawing software, save the file as standard picture file like JPG, GIF, or PNG.
As mentioned, it is always best to have the grid be much larger than the actual drawing canvas. In the example below, we can see the perspective grid far exceeds the boundaries of the painting. Any areas that are in the white region are unseen.
Depending on how the grid is spaced, the lines between the left and the right grid may be hard to see as the grid was originally done using a black fill color. This is easily remedied using layer styles. By double clicking the grid, anyone can apply a 'color overlay' to the black lines.
As there are two layers for the grid, one is assigned a blue color while the other is assigned a red color. The two contrasting colors still help with spacial recognition. If it's still too difficult to see, changing the opacity of one of the grids will help bring out the other.
Overall, for a quick minute of setting up the initial square box, a 2 point perspective grid is easily made using very simple options found in Photoshop. Having said that, this is one of several ways to generate a perspective grid.
For an even quicker method, draw in a few simple horizontal lines, and then apply the perspective transform option directly to it. The drawback is that objects that require technical measurements like a fence, is hard to do without the square grids. Still, the choice is up to the artist to make.