Following on my post on WDYDOYL covering a new retaining wall, here are a few details on how this was created. I needed to cover 15 feet of wall and did not want to spend that much on the prefab flexible sheets - but they look really nice - I was tempted.
Image of 2 sections in place but unfinished.
Close up of the stone detail. The top is scribed to resemble a cap stone. Once in place I will go back and detail the cap stone seams. I prefer to change the brick widths as little as well as gouge out bits here and there.
Going in reverse order - I found it easier to scribe the first couple of rows to give an idea on size. After that I skipped rows to make sure the joints were roughly aligned. I like to use a tapered clay modeling tool here as it easier to clear out the space between the bricks. Using a hobby knife can achieve similar results. The tool has a slight "v" shape to it.
I have done the lay down the straight edge and scribe each individual line in the past. It works, its tedious and I rarely get the horizontal lines parallel. Below is a simple scribing tool for consistent horizontal lines. I did get a little bit of wander but that is a technique thing. Presumably each nail is 3/8 of an inch apart. Did not use a drill press so its clear I did not drill each hole straight. The drywall butts against the stop and multiple light passes are drawn across the drywall to the desired depth.
The drywall here is 2 1/2 inches tall. The top of the image will be the bottom so the bit of variance will not be noticeable.
A sample run showing the paper removed from the drywall. I still have to get better at this, but try not to soak the underside of the drywall paper you do not want to remove. I found anything more than 16 inches long is asking for trouble as the material cracks easily - it has to be supported along its entire length. Most of my finished sheets have at least one crack, but it closes cleanly and is not apparent unlike below. The material holds water and stays damp for quite a while. I got the paper off after 4 wet and peel attempts. I would be better to apply the water and cover with a damp rag to help the water penetrate - but who has time for that??? A steel scrubbing pad was most helpful in removing the final layer of paper. This pad is just a bunch of steel turning gathered into a pad - I 've seen them out of stainless steel and copper in the kitchen/cleaning area.
Hope you find this helpful - I had one of those "why did I not think f that moment" when first told of this modeling technique. Supposedly guys use this for HO scale buildings. Cannot imagine the time involved.