I made the models of the walls in Maya. The windowless wall was pretty simple and straightforward, but the windowed wall was a bit more complex. I ran into problems with the UV map. I thought I would be able to use the automatically generated UV map, but it didn't work out too well. So, I had to select each face that was facing the same way and map the UVs by hand. Some of the faces were tiny, so missing some of them was pretty easy to do. Eventually I got everything mapped and rearranged the UVs as well as I could. Then, I brought the model into Substance Painter. I applied the groutless stone wall texture, and then moved on to texturing the window frame. I added a wood texture. Then, I tried to add a dirt generator, but for some reason, it wasn't working the way I had hoped. So instead, I used a fill layer with a dark brown plastic material and painted out where I wanted some discoloration. Then I added in some cracks. Then, I adjusted the color and opacity of the glass, and it was done. I didn't want the wall to look too dilapidated, so I went for some subtle effects of wear and tear. I really like the way it turned out!